heart health

The Good Cholesterol Myth

by

Is Everything You Knew About HDL Wrong?

Author: Dr. Stephen Chaney 

HDL CHolesterolOver the past couple of weeks” I have talked about one of the greatest strengths of the scientific method – namely that investigators constantly challenge, and occasionally disprove, existing paradigms. That allows us to discard old models of how things work and replace them with better ones.

Two weeks ago, I shared a study that disproved the myth that low to moderate alcohol consumption is healthier than total abstinence.

Last week I shared a study that disproved the myth about chocolate helping you lose weight weight.

This week I tackle the “good” cholesterol myth. I will share several studies that challenge the belief that HDL cholesterol is good for your heart.

The belief that HDL is good for your heart has all the hallmarks of a classic paradigm.

  • It is supported by multiple clinical studies.
  • Elaborate metabolic explanations have been proposed to support the paradigm.
  • It is the official position of most medical societies, scientific organizations, and health information sites on the web.
  • It is the recommendation of most health professionals.
  • It has been repeated so often by so many trusted sources that everyone assumes it must be true.

Once we accept the HDL/heart health paradigm as true, we can construct other hypotheses on that foundation. For example:

  • Raising your HDL levels naturally takes effort. Pharmaceutical companies have been pursuing the “magic pill” that raises HDL levels without any effort on your part.
  • Low carb diets like the Keto and Paleo diets are high in saturated fat. The low carb enthusiasts claim this is a good thing because saturated fat raises HDL levels, and HDL is good for your heart.

But what if the paradigm that HDL is good for your heart isn’t true? What if it is a myth? These hypotheses would be like the parable of a house built on a foundation of sand. They will be washed away as soon as the paradigm is critically tested.

Do Drugs That Increase HDL Levels Work?

The first hint that the HDL/heart health paradigm might be faulty happened when a pharmaceutical company developed a drug that selectively increased HDL levels.

The drug company thought they had found the goose that laid golden eggs. Just imagine. People wouldn’t have to lose weight, exercise, or change their diet. They could simply take a pill and dramatically decrease their heart disease risk. A drug like that would be worth billions of dollars.

The problem was that when they tested their drug (torcetrapib) in clinical trials, it had absolutely no effect on heart disease outcomes (AR Tall et al, Atherosclerosis, Thrombosis, and Vascular Biology 27:257-260, 2007).

The pharmaceutical company couldn’t believe it. Raising HDL levels just had to reduce heart disease risk. They concluded they didn’t have the right drug, and they continued to work on developing new drugs.

That was 18 years ago, and no HDL-increasing drug has made it to market. Have they just not found the right drug, or does this mean the HDL/heart health paradigm is incorrect?

Does Saturated Fat Decrease Heart Disease Risk?

Now let’s turn to two claims of low carb enthusiasts.

#1: Saturated fats decrease your risk of heart disease in the context of a low carb diet. I have debunked that claim in several previous issues of “Health Tips From The Professor”. But let me refer you to two articles here – one on saturated fat and heart disease risk and one on low-carb diets.

#2: Saturated fats decrease heart disease risk because they raise HDL levels. This is the one I will address today.

The idea that saturated fats decrease heart disease risk because they raise HDL levels is based on a simplistic concept of HDL particles. The reality is more complex. Several clinical studies have shown:

  • The type of fat determines the property of the HDL particles.
    • When polyunsaturated fats predominate, the HDL particles have an anti-inflammatory effect. When saturated fats predominate, the HDL particles have a pro-inflammatory effect.
  • Anti-inflammatory HDL particles relax the endothelial cells lining our blood vessels. That makes the lining of our blood vessels more pliable, which improves blood flow and reduces blood pressure.
    • Anti-inflammatory HDL particles also help reduce inflammation of the endothelial lining. This is important because an inflamed endothelial lining is more likely to accumulate fatty plaques and to trigger blood clot formation that can lead to heart attacks and strokes.

So, the question becomes, “What good is it to raise HDL levels if you are producing an unhealthy, pro-inflammatory HDL particle that may increase the risk of high blood pressure, heart attacks, and strokes?”

In short, these studies suggest it isn’t enough to just focus on HDL levels. You need to ask what kind of HDL particles you are creating.

So, let’s look at experiments that have challenged the HDL/heart health paradigm.

Is HDL Good For Your Heart?

strong heartOnce the studies were published showing that…

  • Drug-induced increase of HDL levels without any change in health habits is not sufficient to decrease heart attack risk, and…
  • Not all HDL particles are healthy. There are anti-inflammatory or pro-inflammatory HDL particles, which are likely to have opposite effects on heart attack risk…

…some people started to question the HDL/heart health paradigm. And one group came up with the perfect study to test the paradigm.

But before I describe the study, I need to review the term “confounding variables”. Here is a brief synopsis:

  • The studies supporting the HDL/heart health paradigm are association studies. Association studies measure the association between a single variable (in this case, increase in HDL levels) and an outcome (in this case, heart disease events, heart disease deaths, and total deaths).
  • Associations need to be corrected for other variables known to affect the same outcome (things like age, gender, smoking, and diabetes would be examples in this case).
  • Confounding variables are variables that also affect the outcome but are unknown or ignored. Thus, they are not used to correct the associations, which can bias the results.

The Good Cholesterol Myth

The authors of this study (M Briel et al, BMJ 2009:338.b92) observed that most interventions that increase HDL levels also lower LDL levels. Lowering LDL is known to decrease the risk of heart disease deaths. But this effect had been ignored in most studies looking at the association between HDL and heart disease deaths.

They hypothesized that the change in LDL levels was a confounding variable that had been ignored in previous studies and may have biased the results.

To test this hypothesis the authors searched the literature and identified 108 studies with 299,310 participants that:

  • Compared the effect of drugs, omega-3 fatty acids, or diet with either a placebo or usual care.
  • Measured both HDL and LDL levels.
  • Measured reduction in cardiovascular risk.
  • Had a randomized control design.
  • Lasted at least 6 months.

They found that every 10 mg/dl decrease in LDL levels in these studies was responsible for a:Heart Disease Study

  • 1% reduction in heart disease events (both heart disease deaths and non-fatal heart attacks).
  • 2% reduction in heart disease deaths.
  • 4% reduction in total deaths.

After correcting for the effect of decreased LDL levels on these heart disease outcomes, the increase in HDL levels had no statistically significant effect on any of the outcomes.

The authors concluded, “Available data suggest that simply increasing the amount of circulating HDL cholesterol does not reduce the risk of coronary heart disease events, coronary heart disease deaths, or total deaths. The results support reduction in LDL cholesterol as the primary goal for lipid modifying interventions.”

In other words, this study:

  • Supports the author’s hypothesis that LDL levels were a confounding variable that biased the studies supporting the HDL/heart health paradigm.
  • Concludes that increasing HDL levels has no effect on heart disease outcomes, thus invalidating the HDL/heart health paradigm.

In short, this study destroyed the “good” cholesterol myth.

Is Everything You Knew About HDL Wrong?

Peek Behind The CurtainDoes that mean that everything you knew about HDL is wrong? Not exactly. It just means that you may need to change your perspective.

Don’t focus on HDL levels. Peek behind the curtain and focus on what’s behind the HDL levels. For example:

  • Losing weight when overweight increases HDL levels. But the decrease in heart disease outcomes is more likely due to weight loss than to the increase in HDL levels.
  • Exercise increases HDL levels. But the decrease in heart disease outcomes is more likely due to exercise than to the increase in HDL levels.
  • Reversing pre-diabetes or type 2 diabetes increases HDL levels. But the decrease in heart disease outcomes is more likely due to the reversal of diabetes than to the increase in HDL levels.
  • High-dose omega-3 fatty acids increase HDL levels. But the decrease in heart disease outcomes is more likely due to the omega-3 fatty acids than to the increase in HDL levels.
  • The Mediterranean diet increases HDL levels. But the decrease in heart disease outcomes is more likely due to the diet than to the increase in HDL levels.

And if you want to go the drug route:

  • Statins and some other heart drugs increase HDL levels, but the reduction in heart disease outcomes is probably due to their effect on LDL levels rather than their effect on HDL levels.

On the other hand:

  • Saturated fats increase HDL levels. But saturated fats increase heart disease risk and create pro-inflammatory HDL particles. So, in this case the increase in HDL levels is not a good omen for your heart.
  • Drugs have been discovered that selectively increase HDL levels. However, there is nothing of value behind this increase in HDL levels, so the drugs have no effect on heart disease outcomes.

The Bottom Line 

In this article I discuss several studies that have challenged the good cholesterol myth – the belief that HDL is good for your heart.

For example, one group of investigators analyzed the studies underlying the HDL/heart health paradigm. They hypothesized that these studies were inaccurate because they failed to account for the effects of LDL levels on heart disease outcomes.

After correcting for the effect of decreased LDL levels on heart disease outcomes in the previous studies, the authors showed that increases in HDL levels had no significant effect on any heart disease outcome.

The authors concluded, “Available data suggest that simply increasing the amount of circulating HDL cholesterol does not reduce the risk of coronary heart disease events, coronary heart disease deaths, or total deaths. The results support reduction in LDL cholesterol as the primary goal for lipid modifying interventions.”

In other words, this study:

  • Supports the author’s hypothesis that LDL levels were a confounding variable that biased the studies supporting the HDL/heart health paradigm.
  • Concludes that increasing HDL levels has no effect on heart disease outcomes, thus invalidating the HDL/heart health paradigm.

Does that mean that everything you knew about HDL is wrong? Not exactly. It just means that you need to change your perspective. Don’t focus on HDL levels. Focus on what’s behind the HDL levels. For more information on that, read the article above.

For more information on this study, and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

_________________________________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

________________________________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 53 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Eating For A Healthy Heart

by

What Does This Mean For You?

Author: Dr. Stephen Chaney

You may remember the nursery rhyme, “Jack Sprat could eat no fat. His wife could eat no lean…” You may know people who fit these extremes. And in terms of diets these extremes might represent the vegan and keto diets in today’s world.

The nursery rhyme assures us that, “…between them they licked the platter clean.” But were their diets equally healthy? Which of them would have been more likely to live a long and healthy life?

And, since this is Heart Health Month, we might ask, “Which diet would have been better for their hearts?”

If you search Mr. Google – even with AI assist – you might be confused. That’s because AI bases its recommendations on the quantity of posts, not the accuracy of posts. And lots of media influencers recommend both diets, and just about every popular diet in between for heart health.

But what does good science say on the topic of heart healthy diets? Fortunately, a recent comprehensive review and meta-analysis (G. Riccardi et al, Cardiovascular Research, 118: 1118-1204, 2022) has answered that question.

How Was The Study Done?

clinical studyThe investigators reviewed 99 clinical studies with tens of thousands of participants that looked at the associations between foods or food groups and heart disease risk.

Most of the studies were “prospective cohort” studies in which:

  • Populations are divided into groups (cohorts) based on the foods they consume…
  • …and followed for a number of years (this is where the term “prospective” comes from)…
  • …and at the end of the study, the association between food and heart outcomes is measured.

However, the review also included several major randomized controlled clinical trials, including:

  • The DASH diet study.
  • The Lyon Diet Heart study.
  • The PREDIMED study.

Eating For A Healthy Heart

strong heartHere are the findings of the study. Most will sound very familiar. But you will note some subtle differences based on recent data.

The overall summary was that for a healthy adult population:

  • Low consumption of salt and foods of animal origin…
  • …and increased intake of plant foods…
  • …are associated with reduced heart disease risk.

Of course, we have known that for years. It’s when they broke the data down further that it became more interesting.

Foods Of Animal Origin:

  • Processed meats increase heart disease risk. A single serving of processed meat is associated with a 27% to 44% increased risk of heart disease. This is not new.
  • Unprocessed red meat is also associated with increased risk of heart disease, but this association is not as Steakconsistent as for processed meats. The authors noted that some of this may be due to differences in saturated fat content or cooking methods of the red meats included in individual studies.

But this analysis also showed that the effect of red meat on heart disease risk may be dose dependent. For example:

    • The studies they reviewed suggested that consuming ≥2 servings per day of red meat is associated with a 27% increased risk of heart disease. However, consuming <3 servings per week may not increase risk.
    • The idea that the effect of red meat on heart disease risk may be dose-dependent is novel. However, the authors said we also need to ask what replaces red meat in the diet. They postulated that when red meat consumption is decreased, it is often replaced with healthier protein sources.
  • White meat such as poultry does not appear to affect heart disease risk. This has been predicted by earlier reports, but this analysis strengthens those predictions.
  • Fish consumption decreases heart disease risk. This is not new. But this review added precision about recommended fish intake (2-4 servings/week) and a couple of caveats:
    • The heart benefits of fish may be due to their omega-3 content and may not apply equally to fish with lower omega-3 content.
    • The authors also expressed concerns about the sustainability of high-omega-3 fish populations. I would also add that our oceans are increasingly polluted, so contamination is another concern.
  • Egg consumption up to one egg/day does not appear to increase heart disease risk. This is consistent with the are eggs good for youcurrent American Heart Association recommendations.

However, the authors noted that the effect of eggs on serum cholesterol, and hence heart disease risk depends on several factors.

    • Genetics, obesity, and diabetes can make it more difficult to regulate serum cholesterol levels. For these individuals, eggs may need to be eaten only sparingly.
    • Diets low in saturated fat and high in fiber from plant foods help the body regulate serum cholesterol. Several studies suggest that eggs may decrease heart disease risk in the context of this type of diet.
  • Dairy: Neither low-fat nor high-fat dairy foods appear to influence heart disease risk. This is different from the standard recommendation to consume low-fat dairy foods. But it is in line with the trend of recent research studies on dairy and heart disease.

Once again, there were a couple of caveats:

    • There is increasing evidence that fermented dairy foods may decrease heart disease risk which may explain why certain high-fat cheeses and other high-fat fermented dairy foods appear to have a neutral or slightly beneficial effect on heart disease risk.
    • As with eggs the effect of high-fat dairy foods on heart disease risk may be influenced by genetics and diet context.

Foods Of Plant Origin: The effect of plant foods have been known for some time, and the most recent studies included in this analysis have not changed those conclusions.

  • Fruits and Vegetables consistently reduce heart disease risk in multiple studies. In each case, the optimal Vegan Foodsintake appears to be about 2 servings of each per day which provides an 18-21% risk reduction for vegetables and a 21-32% risk reduction for fruits.
  • Legumes (beans and peas) also consistently reduce heart disease risk in multiple studies. At the optimal intake of around 4 servings per week the risk reduction is around 14%.
  • Nuts also consistently reduce heart disease risk. At the optimal intake of around one serving (a handful) per day, the risk reduction is around 25%.
  • Cereals (grains) were divided into 3 categories:
    • Refined carbohydrates with a high glycemic index (e.g., white rice, white bread) are associated with increased heart disease risk in multiple studies probably due to their effect on blood sugar levels. And the increased risk is significant (Around 66% higher risk for every 2 servings).
    • Refined carbohydrates with a low glycemic index (e.g., pasta, corn tortillas) show an inconsistent effect on heart disease risk.
    • Whole grains are consistently associated with a lower heart disease risk. Two servings of whole grains per day are associated with a 25%-34% decreased risk.

Miscellaneous Foods:

  • Soft Drinks are associated with increased heart disease risk. One serving per day increases the risk by around 15-22% and recent evidence suggests that artificially sweetened soft drinks offer no heart health benefits compared to sugar sweetened soft drinks.
  • Coffee and Tea are both associated with decreased heart disease risk. For coffee the optimal benefit may occur at around 3 cups/day. Higher levels may have an adverse effect on heart disease risk.

Summary of Heart Health Recommendations

ScientistIf you are thinking that was a lot of information, the authors provided a numerical summary of their recommendations for a heart-healthy diet. They are:

  • Two servings per day of vegetables, fresh fruits, and whole grains.
  • One serving per day of nuts and seeds, low-glycemic index refined cereals, extra-virgin olive oil or non-tropical vegetable oils, and yogurt.
  • Four servings per week of legumes and fish.
  • No more than 3 servings per week of white meat, eggs, cheese, and milk.
  • No more than 2 servings per week of high-glycemic index refined starchy foods, red meat, and butter.
  • Only occasional consumption of processed meats.

What Does This Study Mean For You?

QuestionsOf course, nobody wants to follow a “diet by the numbers”. If you are like most of us, you want flexibility and you want to be able to eat some of your favorite foods. So, let me put these recommendations into a more “user friendly” form.

If you want a healthy heart:

  • Whole, unprocessed or minimally processed, plant foods are your friends.
  • Your heart-healthy foundation should be fruits, vegetables, whole grains, nuts and seeds, healthy plant oils, and legumes.
  • Your heart-healthy foundation can also include fermented dairy foods and low-glycemic index refined grains.
  • Your “go-to” beverages should be water, tea (both caffeinated and herbal teas), and coffee. You should avoid soft drinks and other sugar-sweetened or artificially sweetened beverages.
  • Once you have achieved a heart-healthy foundation you can add a few servings per week of white meat, eggs, cheese, and dairy, even high-fat dairy.
  • If you have good adherence to the heart-healthy foundation described above and no genetic or health issues that increase your risk of heart disease, you can probably eat more of these foods.
  • Conversely, if your adherence to the heart-healthy foundation is poor and/or you are at high risk of heart disease, you may wish to consume less of these foods.
  • If you have good adherence to the heart-healthy foundation, you can also add up to 1-2 servings of high-glycemic index refined carbohydrates, red meat, or butter per week. With red meat, you may want to consider it as a garnish that adds flavor to a plant-based meal rather than the centerpiece of the meal.
  • You should eat processed meats seldom or never.

The Bottom Line

A new comprehensive review and meta-analysis of 99 clinical studies with tens of thousands of participants has updated the correlation between foods and heart disease risk.

Many of the recommendations based on this analysis are identical to previous recommendations for a heart-healthy diet.

But there are some subtle changes to those recommendations based on the latest data.

For more details about this study and what a heart-healthy diet might look like for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

_______________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

How Much Should You Walk?

by

Walking Your Way To Health 

Author: Dr. Stephen Chaney 

Overweight People ExercisingYou’ve made your New Year’s resolutions. And if you are like millions of Americans, you may already be making plans to join a gym, get a personal trainer, or join a spin class.

The problem is these are all expensive options. And a good portion of that money is wasted. To put it into perspective, let’s look at some statistics

  • Around 6 million Americans buy gym memberships every January.
    • 67% of those memberships are never used.
    • For those memberships used in January, another 50% are not in use 6 months later.
  • Americans spend about 1.6 billion dollars on unused gym memberships every year.
    • And that doesn’t include those gym memberships that are only occasionally used.

If you want to get fit and healthy in the new year, perhaps you should consider a less expensive option – like walking. Your only investments are a good pair of walking shoes and a device that keeps track of the number of steps you take (eg, Fitbit, smart watch, or smart phone).

You still may give up on your New Year’s goal of getting fitter at some point. But you won’t have wasted so much money.

Of course, you probably have some questions about the benefits of walking, such as:

1) Is walking enough to significantly improve my fitness and health?

2) How far (how many steps) should I walk?

3) How fast should I walk?

Fortunately, two recent studies (B del Pozo-Cruz et al, JAMA Internal Medicine, 182: 1139-1148, 2022) and (J del Pozo-Cruz et al, Diabetes Care, 45: 2156-2158, 2022) have answered all three questions.

How Were These Studies Done?

clinical studyThe first study (B del Pozo-Cruz et al, JAMA Internal Medicine, 182: 1139-1148, 2022) followed 78,500 participants (average age 61, 55% female, 97% white) enrolled in the UK Biobank study for an average of 7 years.

At the time of enrollment, each participant was given an accelerometer (a device that measures the number and frequency of steps) to wear on their dominant wrist for 24 hours/day for 7 days. The investigators used the accelerometer data to categorize several types of physical activity.

  • Daily step counts (the average number of steps per day for 7 days). These step counts were further subdivided into two categories:
    • Incidental steps (It was assumed that ˂40 steps/min represented steps taken that were incidental to normal daily activities).
    • Purposeful steps (It was assumed that ≥40 steps/min represented steps taken as part of planned exercise).
  • Stepping intensity (the highest frequency of steps/min averaged over 30 min intervals for all 7 days).

At the end of the study, each of these variables was correlated with the risk of premature deaths due to all causes, cancer, and heart disease.

The second study (J del Pozo-Cruz et al, Diabetes Care, 45: 2156-2158, 2022) was similar except that it:

  • Used data from 1687 adults (average age = 55, 56% male, with diabetes or prediabetes when the study began) in the 2005-2006 National Health and Nutrition Examination Survey in the US.
  • Followed participants for 9 years instead of 7.
  • Only measured total steps/day.
  • Correlated total steps per day with premature death for participants who already had prediabetes or diabetes when they entered the study.

Walking Your Way To Health

woman walking dogStudy 1 looked at the effect of walking on health outcomes in multiple ways.

#1: Increase in number of steps/day:

  • On average study participants took an average of 7200 steps per day, but this ranged from a low of 3,200 steps/day to a high of 12,200 steps/day.
  • Each increase of 2,000 steps/day was associated with a:
    • 8% decrease in all-cause mortality.
    • 11% decrease in cancer mortality.
    • 10% decrease in heart disease mortality.
  • Overall, increasing from 3,200 steps/day to 10,000 steps/day decreased all-cause, cancer, and heart disease mortality by around 36%.
  • There was no minimum threshold to this beneficial effect of walking on the risk of premature death.
  • The benefits of walking appeared to plateau at 10,000 steps/day.

#2: Increase in number of incidental steps/day (steps taken that are incidental to normal daily activities):

  • On average study participants took 3240 incidental steps/day, but this ranged from a low of 2,100 steps/day to a high of 4,400 steps/day.
  • Each 10% increase in incremental steps/day was associated with a:
    • 6% decrease in all-cause mortality.
    • 6% decrease in cancer mortality.
    • 10% decrease in heart disease mortality.

#3: Increase in number of purposeful steps/day (steps taken as part of planned exercise):

  • On average study participants took 4,600 purposeful steps/day, but this ranged from a low of 1,600 steps/day to a high of 8,600 steps/day.
  • Each 10% increase in purposeful steps/day was associated with a:
    • 7% decrease in all-cause mortality.
    • 8% decrease in cancer mortality.
    • 10% decrease in heart disease mortality.

#4: Increase in speed of walking or cadence. The measurement they used was “peak-30 cadence” – the Walking Fasthighest average steps/min during a 30-minute interval within a day:

  • On average study participants had a “peak-30 cadence” of 76 steps/min, but this ranged from a low of 47 steps/min to a high of 109 steps/min.
  • Each 10% increase in “peak-30 cadence” was associated with a:
    • 8% decrease in all-cause mortality.
    • 9% decrease in cancer mortality.
    • 14% decrease in heart disease mortality.
  • The benefits of walking rapidly (increase in “peak-30 cadence”) were in addition to the benefits seen by increasing the number of steps per day.
  • Overall, increasing from a “peak-30 cadence” of 47 steps/min to 109 steps/min decreased all-cause, cancer, and heart disease mortality by an additional 34%.
  • There was no minimum threshold to this beneficial effect of increasing “peak-30 cadence” (the speed of walking) on the risk of premature death.
  • The benefits of increasing “peak-30 cadence” appeared to plateau at 100 steps/min.

strong heart#5 Effect of walking on the prevention of heart disease and cancer: The investigators measured this by looking at the effect of walking on the “incidence” of heart disease and cancer (defined as new diagnoses of heart disease and cancer) during the study. They found.

  • Each 2,000-step increase in the total number of steps/day decreased the risk of developing heart disease and cancer by 4% during this 7-year study.
  • Each 10% increase in the number of purposeful steps/day decreased the risk of developing heart disease and cancer by 4% during this study.
  • Each 10% increase in “peak-30 cadence” decreased the risk of developing heart disease and cancer by 7% during this study.

The authors concluded, “The findings of this population-based…study of 78,500 individuals suggest that up to 10,000 steps/day may be associated with a lower risk of mortality and cancer and CVD incidence. Steps performed at a higher cadence may be associated with additional risk reduction, particularly for incident disease.”

Study 2 extended these findings to diabetes. They started with participants that had either prediabetes or diabetes diabetesand followed them for 9 years. They found that:

  • Study participants with prediabetes ranged from a low of 3,800 steps/day to a high of 10,700 steps/day.
    • Prediabetic participants walking 10,700 steps/day were 25% less likely to die during the study than participants walking only 3,800 steps/day.
  • Study participants with diabetes ranged from a low of 2,500 steps/day to a high of 10,200 steps/day.
    • Diabetic participants walking 10,200 steps/day were also 25% less likely to die during the study than participants walking only 2,500 steps/day.
  • Even small increases in the number of steps per day decreased the risk of premature death for both prediabetic and diabetic participants.
  • Once again, 10,000 steps/day appeared to be the optimal dose to lower the risk of premature death for both diabetic and prediabetic patients.

The authors of this study concluded, “Accumulating more steps/day up to ~10,000 steps/day may lower the risk of all-cause mortality of adults with prediabetes and diabetes.”

How Much Should You Walk?

Walking CoupleThat was a lot of information. You are probably wondering what it means for you. Let’s start with the big picture:

  • Going from couch potato to 10,000 steps per day may reduce your risk of premature death due to all causes, cancer, and heart disease by 36% (24% if you are already prediabetic or diabetic).
  • Increasing the speed with which you walk from 47 steps/min to 109 steps/min sustained for 30 minutes may reduce your risk of premature death by an additional 34%.

In other words, simply walking more and walking faster can have a significant effect on your health. I am not recommending walking as your only form of exercise. I’m just saying not to consider it inferior to other forms of exercise.

  • There is no lower limit to the benefits of walking. Even small increases in the number of steps/day you take and the speed with which you walk may have a beneficial effect on your health.

In other words, you don’t need to speed walk 10,000 steps/day to reap a benefit from walking. Even small increases are beneficial. That’s good news for those of you who may not be able to speed-walk long distances. It also means that if you are a couch potato, you don’t need to attempt 10,000 steps at high speed from day 1. You can work up to it gradually.

  • Incidental walking (walking that is incidental to your daily activities) is almost as beneficial as purposeful walking (walking as part of a planned exercise).

That’s good news for those of you who may not have time for long walks. It also means that advice like “park your car at the far end of the parking lot and walk” or “take the stairs rather than the elevator” can have a meaningful impact on your health.

  • The benefits of walking appear to max out at around 10,000 steps per day and a cadence of 100 steps/min sustained for 30 minutes.

That means once you get to those levels, it’s time to consider adding other kinds of exercise to your regimen. More and faster walking may offer little additional benefit.

Finally, in the words of the authors, “This information could be used to motivate the least active individuals to increase their steps and the more-active individuals to reach the 10,000-step target.”

The Bottom Line 

You’ve made your New Year’s resolutions. And if you are like millions of Americans, you may already be making plans to join a gym, get a personal trainer, or join a spin class.

If you want to get fit and healthy in the new year, perhaps you should also consider a less expensive option – like walking.

Of course, you probably have some questions about the benefits of walking, such as:

  1. Is walking enough to significantly improve my fitness and health?

2) How far (how many steps) should I walk?

3) How fast should I walk?

Fortunately, two recent studies have answered all three questions. They found:

  • Going from couch potato to 10,000 steps per day may reduce your risk of premature death due to all causes, cancer, and heart disease by 36% (24% if you are already prediabetic or diabetic).
  • Increasing the speed with which you walk from 47 steps/min to 109 steps/min sustained for 30 minutes may reduce your risk of premature death by an additional 34%.
  • There is no lower limit to the benefits of walking. Even small increases in the number of steps/day you take and the speed with which you walk may have a beneficial effect on your health.
  • Incidental walking (walking that is incidental to your daily activities) is almost as beneficial as purposeful walking (walking as part of a planned exercise).
  • The benefits of walking appear to max out at around 10,000 steps per day and a cadence of 100 steps/min sustained for 30 minutes.

In the words of the authors of these studies, “This information could be used to motivate the least active individuals to increase their steps and the more-active individuals to reach the 10,000-step target.”

For more details on these studies and what they mean for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

 _____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 ______________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

600th Issue Celebration

by

Nutrition Advances Over The Last Two Years

Author: Dr. Stephen Chaney 

celebrationIn the nearly twelve years that I have been publishing “Health Tips From The Professor”, I have tried to go behind the headlines to provide you with accurate, unbiased health information that you can trust and apply to your everyday life.

The 600th issue of any publication is a major cause for celebration and reflection – and “Health Tips From The Professor” is no different.

I am dedicating this issue to reviewing some of the major stories I have covered in the past 100 issues. There are lots of topics I could have covered, but I have chosen to focus on three types of articles:

  • Articles that have debunked long-standing myths about nutrition and health.
  • Articles that have corrected some of the misinformation that seems to show up on the internet on an almost daily basis.
  • Articles about the issues that most directly affect your health.

Here are my picks from the last two years:

Weight Loss Diets

weight lossSince it is almost January, let’s start with a couple of articles about diet and weight loss (or weight gain). I have covered the effectiveness of the Paleo, Keto, Mediterranean, DASH, vegetarian, and Vegan diets for both short and long-term weight loss in my book “Slaying The Food Myths”, so I won’t repeat that information here. Instead, I will share a few updates from the past 100 issues.

Is Time-Restricted Eating Better Than Other Diets? Time-restricted eating is one of the latest fads. But is it really better than other diets for weight loss and improved health? In this article I reviewed two studies that compare time-restricted eating with diets that do not restrict time of eating but cut calories to the same extent. You may be surprised at the results.

Can You Lose Weight Without Dieting? In this article I share 8 tips for losing weight without going on a diet. The article is based on research by Dr. Brian Wansink, a behavioral psychologist who specializes in studying how external clues influence our eating patterns. As you might suspect his 8 tips for losing weight have nothing to do with counting calories or going on restrictive diets.

Healthy Diets

dairy foodsIs Whole Fat Dairy Healthy? For years dietary guidelines have been telling us to select low fat dairy foods. But some health gurus are telling you that isn’t true. They claim whole fat dairy is healthy. So, you are probably wondering, “What is the scoop (as in ice cream) on whole fat dairy?” In this article I look at the study behind the headlines and answer that question. But the answer is not a simple “Yes” or “No”. The answer is more nuanced. It turns out that whole fat dairy is healthier in some diets than in others. 

Are Low Carb Diets Healthy? Are low carb diets good for you or bad for you? It depends on which study you quote. Two major studies in recent years have come to opposite conclusions. In this article I help you sort through the conflicting studies and rephrase the question. Instead of, “Are low carb diets healthy”, the question should be, “Which low carb diets are healthy?”

Are All Plant-Based Diets Healthy? Plant-based diets have acquired a “health halo” in recent years. Your mama told you to eat your fruits and vegetables. And many health gurus have been telling you not to neglect your grains, legumes, nuts, and seeds as well. But some of these foods require a lot of food preparation.

Never fear! The food industry has come to your rescue with a wide variety of processed plant-based foods. No need for food prep. But are they as good for you as the unprocessed plant foods they replace? In this article I review a study that answers that question.

You probably know what that answer is, but the article is worth a read anyway. That is because the study also asks whether vegan and vegetarian diets are healthier than other primarily plant-based diets. And you may not know the answer to that question.

Diet And Heart Disease

egg confusionAre Eggs Bad For You? For years we were told that eggs are bad for us because they contain cholesterol. Then we were told that eggs in moderation may not increase our risk of heart disease. And recently studies have appeared claiming eggs may be good for our hearts. What is the truth about eggs and heart disease? In this article I review a recent study claiming eggs are bad for our heart and put that study into the context of other recent studies to clear up the “eggfusion”.

Which Diets Are Heart Healthy? Every popular diet claims to help you lose weight, reduce your risk of diabetes, and reduce your risk of heart disease. All these claims can’t be true. Which diets deliver on their promises, and which are just pretenders? In this article I review a recent study that answered that question for heart disease.

This study was a very large metanalysis of over 40 studies with 35,548 participants that looked at the effect of different diets on heart disease outcomes. The study identified two diets that significantly reduced the risk of heart disease. There are other diets that might reduce the risk of heart disease, but their benefits have not been proven by high quality clinical studies. They are merely pretenders.

The Dangers Of Processed Foods 

In previous issues of “Health Tips From the Professor” I have shared articles showing that diets high in processed foods are associated with an increased risk of obesity, diabetes, and heart disease. But the story keeps getting worse. Here are two articles on recent studies about processed foods that appeared in “Health Tips From The Professor” in the last two years.

Why Does Processed Food Make You Fat? We already know that eating a lot of highly processed food is likely to make us fat. But what is it about processed food that makes us fat? In this article I review a recent study that answers that question.

This study is interesting for two reasons.

  • It identifies the characteristics of processed foods that make us want to eat more.
  • It identifies some minimally processed foods that have the same characteristics and suggests we should choose minimally processed foods wisely. Simply put, knowledge is power. We may want to avoid minimally processed foods that have the same obesity-inducing characteristics as processed foods.

Do Processed Foods Cause Cancer? Previous studies have shown that processed food consumption is associated with a higher risk of obesity, diabetes, and heart disease. Can it get any worse? In this article I review a recent study that shows processed food consumption is associated with an increased risk of several kinds of cancer.

Maintaining Muscle Mass As We Age

As we age, we begin to lose muscle mass, a process called sarcopenia. Unless we actively resist loss of muscle mass it will eventually impact our quality of life and our health.

We can prevent this loss of muscle mass with resistance exercise, adequate protein intake, and adequate intake of the amino acid leucine. Previous studies have shown people over 50 need more of each of these to maintain muscle mass, but the amount they need has been uncertain until now. Three recent studies have given seniors better guidelines for maintaining muscle mass.

Can You Build Muscle In Your 80s? In this article I review a recent study that enrolled a group of octogenarians in a high-intensity exercise program to see if they could gain muscle mass. They were able to increase their muscle mass, but the intensity of the exercise required may surprise you.

Optimizing Protein Intake For Seniors. In this article I review two recent studies that looked at the amount, timing, and kind of protein needed for seniors in their 60s and 70s to maximize gain in muscle mass.

How Much Leucine Do Seniors Need? In this article I review a recent study that determined the amount of leucine seniors in their 70s need to optimize gains in muscle mass and strength.

The Benefits And Risks Of Supplementation

Omega-3s And Heart DiseaseIf you listen to Big Pharma or the medical profession, you hear a lot about the “risks” of supplementation and very little about the benefits. In “Health Tips From the Professor” I try to present a more balanced view of supplementation by sharing high-quality studies showing benefit from supplementation and studies that put the supposed risks into perspective.

The Good News About Omega-3s and Stroke. Multiple studies have shown that omega-3 supplementation reduces the risk of ischemic strokes (strokes caused by a blood clot). But it has been widely assumed they might increase the risk of hemorrhagic strokes (strokes caused by bleeding). In this article I review a meta-analysis of 29 clinical studies with 183,000 participants that tested that assumption.

How Much Omega-3s Are Best For Blood Pressure? Multiple studies have shown that omega-3 supplementation can reduce high blood pressure. But the doses used vary widely from one study to the next. In this article I review a meta-analysis of 71 double-blind, placebo-controlled clinical studies that determined the optimal dose of omega-3s for controlling blood pressure.

Omega-3 Supplements Are Safe. As I said above, it has been widely assumed that omega-3 supplementation increases the risk of bleeding and hemorrhagic stroke. In this article I review the definitive study on this topic. More importantly, it reveals which omega-3 supplements might increase bleeding risk and which do not.

Are Calcium Supplements Safe? Big Pharma and the medical profession have been warning us that calcium supplements may increase heart disease risk. In this article I review the definitive study on this topic.

Prenatal Supplements

prenatal dha supplementIf you are pregnant or thinking of becoming pregnant, your health professional has likely recommended a prenatal supplement. You probably assume that prenatal supplements provide everything you need for a healthy pregnancy. Unfortunately, recent research has shown that assumption is not correct.

Is Your Prenatal Supplement Adequate? In this article I review a study that should serve as a wakeup call for every expectant mother. It showed that most prenatal supplements were woefully inadequate for a healthy pregnancy.

What Nutrients Are Missing In Prenatal Supplements? In this article I review a study that identified additional nutrients that are missing in most prenatal supplements.

Prenatal Supplements Strike Out Again. In this article I review a study that looked at the diet of pregnant women to determine their needs and compared that to the nutrients found in prenatal supplements. Once again, most prenatal supplements were woefully inadequate. Is it, “Three strikes and you are out”?

Exercise

Walking FastWalking Your Way To Health. We have been told that walking is good for our health. But how many steps should you take, how fast should you walk, and does it matter whether these steps are part of your daily routine or on long hikes? In this article I review a study that answers all these questions.

Which Exercise Is Best For Reducing Blood Pressure? If you have high blood pressure, you have probably been told to exercise more. But which exercise is best? In this article I review a study that answers that question. And the answer may surprise you.

Did You Know? 

Question MarkIf you have been reading “Health Tips From the Professor” for a while, you probably know that I enjoy poking holes in popular myths. Here are two new ones I deflated in past two years.

Is Low Alcohol Consumption Healthy? You have probably heard that low alcohol intake (that proverbial glass of red wine) is good for you. But is that true? In this article I review a recent study that shows that myth was based on faulty interpretation of the data and provides a more nuanced interpretation of the data.

Is HDL Good For Your Heart? You have been told that increasing your HDL levels reduces your risk of heart disease so many times it must be true. But is it? In this article I review HDL metabolism and a recent study to provide a more nuanced interpretation of the relationship between HDL and heart disease risk.

How To Talk With Your Doctor About Cancer 

Because of my years in cancer research, I am often asked whether someone should follow their oncologist’s advice and go on a recommended chemotherapy or radiation regimen. Of course, it would be unethical for me to provide that kind of advice.

In this article I tell you the questions to ask your oncologist about the prescribed treatment regimen, so you can make an informed decision. However, I also recommend you only ask these questions if you can handle the answers.

The Bottom Line

I have just touched on a few of my most popular articles above. You may want to scroll through these articles to find ones of interest to you that you might have missed over the last two years. If you don’t see topics that you are looking for, just go to https://chaneyhealth.com/healthtips/ and type the appropriate term in the search box.

In the coming years, you can look for more articles debunking myths, exposing lies and providing balance to the debate about the health topics that affect you directly. As always, I pledge to provide you with scientifically accurate, balanced information that you can trust. I will continue to do my best to present this information in a clear and concise manner so that you can understand it and apply it to your life.

Final Comment: You may wish to share the valuable resources in this article with others. If you do, then copy the link at the top and bottom of this page into your email. If you just forward this email and the recipient unsubscribes, it will unsubscribe you as well.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

_______________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 _______________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com/lifestylechange/.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Is Olive Oil Overrated?

by

What Is The Truth About Olive Oil And You? 

Author: Dr. Stephen Chaney 

You may have seen headlines claiming that olive oil doesn’t deserve its “health halo”. It isn’t as healthy as many experts have claimed. It is overrated.

These headlines aren’t referring to the scandalous practice of selling “extra virgin” olive oil that contains cheaper oils. That is another topic for another day.

The headlines are claiming that, while the Mediterranean diet is healthy, it is fruits, vegetables, whole grains, legumes, and fish that make the Mediterranean diet healthy. Their claim is that olive oil has little to do with it.

To evaluate these claims I have reviewed the study (AK Krenek et al, Journal of the American Heart Association, Volume 13, Number 15:e035034, July 24, 2024) behind the headlines.

And to provide context, I have also reviewed another recent study (M Guasch-Ferre et al, Journal of the American College of Cardiology, Volume 79, Number 2, 2022).

How Were These Studies Done?

clinical studyThe two studies were very different:

The First Study used a randomized cross-over design to compare high and low olive oil diets.

In the randomized cross-over design participants were randomly assigned to one of the two diets at the beginning of the study. They followed that diet plan for 4 weeks. And after a one week “washout” they followed the other diet plan for 4 weeks. In this type of study each participant serves as their own control.

Study participants (50 obese participants, average age = 64, 75% women, 72% white, ≥ 5% risk of heart disease) were all eating a typical American diet.

Each of the experimental diets was a whole food plant-based diet, with comparable amounts of fruits, vegetables, whole grains, legumes, nuts, and seeds. Both diets were high in fiber, low in added sugar, and contained less than an ounce of animal products a day. In other words, the base diet was a healthy plant-based diet.

Participants in the high olive oil group were asked to add 4 tablespoons/day of extra virgin olive oil to their diet while participants in the low olive oil group were asked to restrict their olive oil intake to < 1 teaspoon/day.

No effort was made to control portion sizes or caloric intake. As we will see below, this was a major weakness of the study. As you might expect, fat intake was significantly greater for those on the high olive oil diet (49% of calories) compared to the low olive oil diet (32% of calories). Consequently, caloric intake was also significantly greater on the high olive oil diet.

All participants met with a dietitian/chef at the beginning of the study and were given access to online training programs and a dietitian hotline for questions. Dietary intake was measured by a 24-hour dietary recall 4-7 times prior to the study and 4 times during each diet period.

Fasting blood and urine samples were collected prior to the study and at the end of each 4-week diet period to measure biomarkers with possible predictive value for heart disease, such as LDL cholesterol.

The Second Study was a prospective cohort study using data obtained from 60,582 women in the Nurses Health Study and 31,801 men in the Health Professionals Follow-Up Study.

In a prospective cohort study a cohort or group of people (in this case, the 60,582 women and 31,801 men in the two studies) are followed over time (in this case for 28 years from1990 to 2018). The study then measures the association between some aspect of their diet and lifestyle (in this case the kind of fat in their diet) and health outcomes at the end of the study (in this case all-cause mortality, cardiovascular mortality, cancer mortality, neurodegenerative disease mortality, and respiratory disease mortality).

A strength of this study was that the diet of all participants was assessed every 4 years, which allowed the investigators to track changes in their diet over time. The intake of most fats was remarkably stable over the entire 28-year duration of the study.

However, as the bad news about margarine and the good news about olive oil entered the popular media, margarine consumption declined, and olive oil consumption increased. Because the investigators were able to track these changes over time, they were able to correct for them in their data analysis.

Is Olive Oil Overrated?

thumbs down symbolResults From The First Study: If we restrict ourselves to statistically significant observations, the results were as follows:

  • Switching from the baseline diet (typical American diet) to either the high olive oil or low olive oil diets for 4 weeks resulted in a significant decrease in total cholesterol, LDL cholesterol, HDL cholesterol, and blood glucose levels.
  • In this case, there was no statistically significant difference between the two diets.

However, when transitioning from the low olive oil diet to the high olive oil diet and from the high olive oil diet to the low olive oil diet, some statistically significant differences were observed.

For example, transitioning from the high olive oil diet to the low olive oil diet resulted in:

  • A 7% decrease in total cholesterol.
  • An 11% decrease in LDL-cholesterol.
  • A 2.2% decrease in HDL-cholesterol.
  • A 2% decrease in blood glucose levels.

And transitioning from the low olive oil diet to the high olive oil diet resulted in:

  • A 14% increase in total cholesterol.
  • A 14% increase in LDL-cholesterol.
  • A 15% increase in HDL-cholesterol.
  • A 17% decrease in blood glucose levels.

The authors of this study said, “Although both [whole food, primarily plant-based] diets improved [risk factors for heart disease], a low olive oil intervention may provide superior LDL-cholesterol lowering in individuals at highest risk [of heart disease]. Future studies are needed to determine if these short-term effects are sustainable and translate to improvements in cardiac outcomes…Nevertheless, a whole food primarily plant-based diet with relatively lower olive oil may be a useful tool for clinicians for improving cardiovascular risk compared with greater olive oil intake.”

The authors also went on to say, “…olive oil may not be the beneficial additive of a Mediterranean diet.”

thumbs upResults From The Second Study:

Higher intake of olive oil (>0.5 tablespoons/day compared to ≤1 teaspoon/day) resulted in:

  • A 19% decrease in the risk of all-cause mortality. And when that was broken down by cause it amounted to:
    • A 19% decrease in the risk of cardiovascular mortality.
    • A 17% decrease in the risk of cancer mortality.
    • A 29% decrease in the risk of neurodegenerative disease mortality.
    • An 18% decrease in the risk of respiratory disease mortality.

In a substitution analysis calculating the effect of consuming 10 g/day of olive oil instead of 10 g/day of:

  • Butter resulted in a 14% decrease in the risk of all-cause mortality.
  • Margarine or dairy fat resulted in a 13% decrease in the risk of all-cause mortality.
  • Mayonnaise resulted in a 9% decrease in the risk of all-cause mortality.
  • Other vegetable oils had no effect on all-cause mortality.
  • Results were similar when the investigators looked at the effect of replacing fats with olive oil on mortality due to cardiovascular disease, cancer, neurodegenerative disease, and respiratory disease.

The authors of the second study concluded, “Higher olive oil intake was associated with lower risk of total and cause-specific mortality. Replacing margarine, butter, mayonnaise, and dairy fat with olive oil was associated with lower risk of mortality.”

How can we reconcile these conflicting viewpoints? Let me start by looking at the flaws in the first study. Then I will summarize the “truth” about olive oil based on what these two studies tell us.

Is The Study Behind The Headlines Misleading?

flawsFirst let me summarize why I consider the study to be misleading. Then I will discuss why the headlines about the study are misleading.

Why The Study Is Misleading: The main conclusion of this study was that adding olive oil to a primarily plant-based diet increased the risk of heart disease. While this study is well-designed in some respects, it is flawed in others. I will summarize the flaws here:

Flaw Number 1: The authors rely on the relative effects of the high and low olive oil diets on LDL-cholesterol levels in predicting the effect of the two diets on heart disease risk. However, there is a major problem with this argument:

  • HDL-cholesterol levels move in the same direction. Both are decreased in the transition from the high olive oil to the low olive oil diet. Both are increased in the transition from the low olive oil to high olive oil diet. The ratio of HDL to LDL cholesterol changes very little, so it is almost impossible to predict what effect these changes will have on heart disease outcomes.

Flaw Number 2: This is related to the flaw I mentioned earlier. No effort was made to control portion size or caloric intake of participants on these diets. The high olive oil diet added 4 tablespoons of olive oil to the low olive oil diet. This significantly increased the fat and caloric intake of participants on the high olive oil diet.

  • Participants lost weight on both diets, but weight loss was significantly greater on the low olive oil diet. In their discussion, the authors admitted that the greater reduction in LDL-cholesterol on the low olive oil diet could have been due to the greater reduction in weight on that diet.

Flaw Number 3: I call this the “straw man” flaw. By adding 4 tablespoons of olive oil to the high olive oil diet the authors created the equivalent of a straw man that was easy knock over. Even if their conclusions were correct, nobody has recommended the addition of 4 tablespoons of olive oil to any diet as a heart-healthy approach.

Mediterraneans don’t add 4 tablespoons of olive oil to their diet. Olive oil is part of the foods they eat and the way they prepare their food.

Why The Headlines Are Misleading: Of course, the headlines were misleading because they ignored the many flaws of the study.

However, I find it amusing that some of the headlines came from “Forks Over Knives” an organization that advocates for a very low-fat plant-based diet. They were using this study to question the value of olive oil as part of a whole-food plant-based diet.

However, when you look at the study, 32% of calories came from fat in the low olive oil diet, and 49% of calories came from fat in the high olive oil diet.

For perspective:

  • The low-fat whole-food plant-based diet recommended by “Forks Over Knives” has <10-15% of calories from fat.
  • The Mediterranean diet typically contains 35-40% of calories from fat.
    • Around 18-19% of that is monounsaturated fat.
    • Around 8% of that is saturated fat.
  • The typical American diet also contains 35-40% of calories from fat.
    • Around 12-14% of that is monounsaturated fat.
    • Around 12% of that is saturated fat.

In other words, the low olive oil diet in this study resembles the fat content of the Mediterranean and typical American diets, not the low-fat whole food plant-based diet recommended by “Forks Over Knives”.

And the high olive oil diet contains fat levels not seen in any natural diet. Except for a few keto enthusiasts, I don’t know of any experts who think getting almost 50% of your calories from any kind of fat is a good thing.

What Is The Truth About Olive Oil And You?

The TruthAs described above, the study behind the headlines is a very small, very short study with multiple flaws. So, you can ignore headlines like “Olive oil is overrated” or “Olive oil doesn’t deserve its health halo.”

The second study I discussed is much larger (92,383 participants) and of much longer duration (28 years). More importantly, it measures health outcomes, not blood biomarkers that might predict health outcomes.

Finally, the second study was not measuring the health benefits of the Mediterranean diet, as many other studies have done. It was looking at the effect of varying olive oil intakes in the American diet. The high olive oil intakes in this study were less than those seen in the Mediterranean diet. This is good news for the average American who may feel overwhelmed trying to adopt to a Mediterranean diet.

This study reinforces previous studies showing that olive oil is healthy. But let me put this into context.

  • Olive oil is not a superfood. This study showed that it is no healthier than other plant oils. It is, however, considered one of the best vegetable oils for sauteing. It is also less susceptible to oxidation than seed oils, although I still recommend you store it in the refrigerator.
  • It is not something you add to your diet. It is something you incorporate into your diet. People who live in Mediterranean regions:
    • Cook with olive oil.
    • Use olive oil in their salad dressings and drizzle a little olive oil on cooked vegetable and pasta dishes instead of adding butter.
    • Dip their bread in olive oil rather than using butter or mayonnaise.
    • Use it in spreads like tapenade or hummus.
    • Use olives in cooking.
  • Finally, look for extra virgin olive oil. That doesn’t mean you need to spend “an arm and a leg”. But I would do a little online research before I bought the cheapest brand at the discount store.

The Bottom Line

You may have seen recent headlines claiming that olive oil is overrated and that it doesn’t deserve its “health halo”. So, I looked at the study behind the headlines.

It was a very small, very short study with multiple flaws. You can forget the headlines.

For context I also reviewed another recent study. It was a much larger (92,383 participants) and longer duration (28 years) study. More importantly, it measured actual health outcomes, not just blood biomarkers that might predict health outcomes.

It concluded that olive oil is good for us. It is healthier than most fats commonly found in the American diet, but it is no healthier than other plant oils.

For more details on these studies, what they mean for you, and how to incorporate more olive oil into your diet read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

______________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_____________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

 

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Are Omega-3 Supplements Safe?

by

The Flaws And Blind Spots In This Study

Author: Dr. Stephen Chaney

Pendulum
Pendulum

Has the omega-3 pendulum swung again? The recent headlines are downright scary. For example:

  • “Fish Oil May Increase the Risk of Stroke and Heart Conditions.”
  • “Fish Oil Supplements May Cause Harm, Study Finds. Is It Time to Ditch Them?”
  • “Fish Oil Supplements May Lead to Heart Problems”.
  • “Regular Use of Fish Oil Supplements Might Increase, Rather Than Lessen, The Risk of First Time Heart Disease and Stroke Among Those in Good Cardiovascular Health.”

Yikes! That sounds bad. Should we be thinking about giving up our omega-3 supplements?

But wait. Just a few weeks earlier we were reading headlines about the benefits and lack of side effects from omega-3 supplements. That’s confusing. Which headlines are correct?

To answer these questions:

  • I will point out the flaws and blind spots in the study.
  • I will strip away the hyperbole and put the headlines into perspective.

How Was The Study Done?

clinical studyThe investigators made use of data from the UK Biobank Study. The UK Biobank Study is a large, long-term study in the United Kingdom which was designed to investigate the contributions of genetic predisposition and environmental exposure [including diet and supplementation] to the development of disease.

The UK Biobank Study enrolled 502,461 participants, aged 40-69 years, between January 1st, 2006 and December 31st, 2010. Participants were followed from entry into the program until March 31st 2021, an average of 11.9 years.

The current study excluded any participants who had a diagnosis of atrial fibrillation, heart failure, heart attack, stroke, or cancer at entry into the study, leaving 415,737 participants.

The participants were:

  • 55% women.
  • Average age of 56 years, with 83.4% of them below 65 years old at entry into the study.
  • 94.5% white.

The study was designed in a unique manner, in that it was designed to test the effect of omega-3 supplements on 6 specific transitions:

  • Primary prevention. This measured the transition of healthy (no diagnosed heart disease) people to either atrial fibrillation, major cardiovascular events, or death.
  • Secondary prevention. This measured the transition from atrial fibrillation to either major cardiovascular events or death.
  • Tertiary prevention. This measured the transition from major cardiovascular events to death.
  • Major cardiovascular events were further broken down to heart attacks, stroke and heart failure.

Participants were asked whether they used fish oil supplements when they entered the study and were categorized as either regular users or non-users. [Note: The users were not asked the dose or brand of fish oil supplements they used.]

Deaths were obtained from the national death registry and disease diagnosis from the National Health Service.

Are Omega-3 Supplements Safe?

omega-3 fish oil supplementHere is what the study found.

Primary Prevention – For healthy individuals (defined as having no diagnosed heart disease) using omega-3 supplements for an average of 11.9 years:

  • Increased the risk of atrial fibrillation by 13%.
  • Did not affect the risk of major cardiovascular events and death were unaffected by omega-3 supplementation.
  • When major cardiovascular events were broken down to their component parts, omega-3 supplementation:
    • Decreased the risk of heart failure by 8%.
    • Increased the risk of stroke by 5% (this was just barely statistically significance).
    • Did not affect the risk of heart attack.

Secondary Prevention – For individuals with atrial fibrillation omega-3 supplementation:

  • Decreased the risk of major cardiovascular events by 9%.
  • Decreased the risk of death by 8%.
  • When major cardiovascular events were broken down into their component parts, omega-3 supplementation:
  • Decreased the risk of heart attacks by 15%.
  • Had no effect on the risk of stroke or heart failure.

Tertiary Prevention – For people who suffered major cardiovascular events during the study omega-3 thumbs upsupplementation:

  • Decreased the risk of death by 8%.

Since this is a very complex set of data, I have coded positive results in green and negative results in red.

And as if these complexities were not enough, when the investigators broke these effects down by population groups:

  • Omega-3 supplementation decreased the transition from healthy to death for men (7% decrease) and participants older than 65 (9% decrease).

I will discuss the significance of these observations below.

The authors concluded, “Regular use of fish oil supplements might be a risk factor for atrial fibrillation and stroke among the general population but could be beneficial for [reducing] progression of cardiovascular disease from atrial fibrillation to major adverse cardiovascular events, and from atrial fibrillation to death.”

In short, they were suggesting that omega-3 supplements should be avoided by the general population because they have no positive benefits and might increase the risk of atrial fibrillation and stroke. But omega-3 supplements may be useful for those who already have heart disease.

Some of the articles you may have read about the study repeated this message. Others just emphasized the negative aspects of the study.

But is this message accurate? Let me start by discussing the flaws, blind spots, and hidden data in this study. Then I will summarize the 3 key findings of the study and tell you what they mean for you.

The Flaws, Blind Spots, And Hidden Data In This Study

flawsFlaws: As I said above, there were two major flaws in the study.

Flaw #1: The study did not identify the dose of supplement used. This is important because the increased risk of atrial fibrillation and stroke is primarily seen in clinical trials using high dose omega-3 supplements.

Flaw #2: This was an association study which cannot prove cause and effect. However, the authors of this study reported it as showing that omega-3 supplement use caused atrial fibrillation and stroke – and all the news reports on the study have repeated that claim.

Flaw #3: Other experts have pointed out that the authors inflated the risks associated with omega-3 supplementation by reporting relative risk rather than absolute risk. Let me try to simplify the distinction.

The risk of atrial fibrillation was 4.24% in the non-supplement users and 4.80% in the omega-3 supplement users. That is an absolute increase in risk of 0.56% (4.80% – 4.24%). This is the increase in risk you actually experience. In contrast, 4.80% is 13% greater than 4.24%, which is how relative risk is calculated.

In response to the questions you are probably thinking:

  • Yes, this is a perfect example of the Mark Twain quote, “There are lies. There are damn lies. And then there are statistics.”
  • Yes, all the percentages reported in this study are based on relative risk and are, therefore, inflated. However, I do not have access to their data, so I cannot tell you the absolute risk associated with their other observations.

Blind Spots: In their paper the investigators recommended against the use of omega-3 supplements to prevent heart disease because their data showed:

  • No benefit of omega-3 supplementation for preventing major cardiovascular events and deaths in a healthy population.
  • But did suggest an increased risk of atrial fibrillation and stroke in that same population.

However, their blind spot was in underestimating the difficulty of showing the benefit of any intervention in a healthy population. The example I always use is statin drugs. Statin Drugs:

  • Dramatically reduce the risk of a second heart attack and/or death in people who have already had a heart attack.
  • Reduce the risk of heart attacks in people who are at high risk of heart attacks.
  • Cannot be shown to reduce the risk of heart attacks in a healthy population.

This study suggests that omega-3 supplements are no different. In this study, omega-3 supplements:

  • Reduced the risk of death in people who had already experienced a major cardiovascular event like a heart attack or stroke.
  • Reduced the risk of major cardiovascular events and death in people with atrial fibrillation, which puts them at high risk for a heart attack or stroke.
  • Could not be shown to reduce the risk of major cardiovascular events or deaths in a healthy population.

Hidden Data: There are some important data that were buried in the text and supplemental figures but were Skepticignored in the concluding remarks of this study and all the articles written about it. For example:

  • The original study and all articles written about the study reported that omega-3 supplementation increased the risk of stroke in otherwise healthy individuals but ignored the observation that omega-3 supplementation decreased the risk of heart failure in that same group.

The second example of hidden data likely represents another blind spot of the authors. They concluded that omega-3 supplementation had no benefit for healthy individuals without asking whether omega-3 supplements might benefit higher-risk subpopulations within this group. To help you understand this statement let me start by giving you some perspective.

As I said above, statin drugs cannot be shown to reduce the risk of heart attacks in a healthy population. But when you include people at high risk of heart disease with healthy people in the dataset, you start to see a reduced risk of heart attacks.

Similarly, with supplements you often see no benefits with the general population, which is what is usually reported in the media. But when you look at higher risk groups within that population, the benefits of supplementation emerge.

This study is no different:

  • For healthy individuals, omega-3 supplementation had no effect on deaths during the 12-year follow-up period.
  • However, omega-3 supplementation reduced the risk of death by 9% for both men and people ≥ 65. These represent two groups with elevated risk of heart disease within the otherwise healthy population.
  • Once again, these data were completely ignored.

What Does This Study Mean For You?

This study made 3 major points:

Point #1: Let me start with the one you’ve heard the most about. The risk of atrial fibrillation and stroke associated with omega-3 supplementation is real. We should not ignore it.

But what this study and most of the reports on the study didn’t tell you is that the risk is dose dependent. The risk is primarily seen with high doses of omega-3s. While no one has done a comprehensive dose response analysis, I can tell you that these side effects are:

  • Seldom reported in clinical studies at doses of 1 gm/day or less.
  • Sometimes reported in clinical studies at doses of ≥2 gm/day.
  • Frequently reported in clinical studies at doses of ≥4 gm/day.

However, atrial fibrillation and stroke occur in a very small percentage of omega-3 users, even at 4 gm/day. At this point we have no idea why some people are susceptible to these side effects and others are not. More research in this area is clearly needed.

Until we know more about who is at risk, my recommendation for people who are trying to reduce the risk of heart disease is to rely on something called the Omega-3 Index to determine your individual omega-3 needs rather than using high-dose omega-3 supplements.

  • The Omega-3 Index measures the amount of omega-3 fatty acids in your tissues. It is determined by the amount of omega-3s you consume and how you metabolize them, so it is individualized to you.
  • An Omega-3 Index of 4% is associated with a high risk of heart disease, while an Omega-3 Index of 8% is associated with a low risk of heart disease. There is no evidence that more than 8% provides additional benefit.
  • Most importantly, it only takes 1-1.6 gm/day of omega-3s to raise your Omega-3 Index from 4% to 8%. At these doses your risk of atrial fibrillation and stroke is extremely small.

For example, a recent meta-analysis of 29 studies with a total of 183,292 participants reported that people with an 8% Omega-3 Index had:

  • Decreased risk of ischemic stroke (stroke due to blood clots) with no detectable increased risk of hemorrhagic stroke (stroke due to bleeding), and…
  • No detectable increased risk of atrial fibrillation.

I recommend getting your Omega-3 Index determined, and if it is low, increasing your omega-3 intake to get it into the 8% range. Some people go from 4% to 8% more rapidly than others, so you may need to repeat the test several times to optimize your Omega-3 Index.

If your health professional doesn’t have access to the Omega-3 Index test, you can order it from https://omegaquant.com (I have no financial stake in this company, but I know it as a reputable source of the Omega-3 Index test).

Does The Professor Plan To Reduce His Intake Of Omega-3 Fatty Acids? Three weeks ago, I shared thatprofessor owl my wife and I have been taking around 3 gm/day of omega-3 supplements for the past 40 years. Now that the association of atrial fibrillation and stroke with high dose omega-3 intake has been firmly established, some of you may be wondering whether we plan to decrease our intake of omega-3 supplements.

The answer is, “No”. Remember that the increased risk of atrial fibrillation and stroke is only seen for a small subset of people taking high-dose omega-3 supplements. If we were part of that subset, we would likely have experienced one of those side effects by now.

However, if you are considering omega-3 supplementation for the first time, you don’t know whether you are part of that subset or not. So, my advice remains the same. Rely on optimizing your Omega-3 Index rather than high-dose omega-3 supplementation.

Point #2: Healthy individuals (those with no symptoms of heart disease) do not benefit from omega-3 supplementation. As I pointed out above, this ignores data from their study, namely.

  • Omega-3 supplementation reduced the risk of heart failure in healthy subjects.
  • Omega-3 supplementation reduced the risk of death in higher risk groups within the healthy population (namely men and people 65 and older).

Confusion Clinical StudiesAs I discussed above, this is a pattern seen with statin drugs and most nutritional supplements. Simply put, you can’t show any benefit of statin drugs or most nutritional supplements in a “healthy” population, but you can show benefit when you focus on higher risk individuals within the “healthy” population.

The problem, of course, is that most of us don’t really know whether we are “healthy” or not. For millions of Americans the first indication that they are at risk from heart disease is sudden death from a heart attack or stroke.

With that in mind, I will leave the decision about whether you want to supplement with omega-3s up to you. But if you decide to supplement, I recommend you optimize your Omega-3 Index rather than using a high dose omega-3 supplement.

Point #3: People with heart disease benefit from omega-3 supplementation. This recommendation is becoming non-controversial, so I won’t comment further other than to say high dose omega-3 supplements are probably not needed unless prescribed by your health professional.

The Bottom Line

You have been asking me about recent headlines saying that omega-3 supplements may increase rather than decrease the risk of heart disease. So, I analyzed the study behind the headlines. The study makes 3 claims:

  • Omega-3 supplements increase the risk of atrial fibrillation and stroke when taken by healthy people.
  • Omega-3 supplements are of no benefit for healthy individuals.
  • Omega-3 supplements are beneficial for people who have heart disease.

In the article above I review the flaws, blind spots, and hidden data in the article and discuss what it means for you.

For more details about this study and what it means for you read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

 ______________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 _______________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Is The Mediterranean Diet Healthy For Women?

by

What Does This Study Mean For You? 

Author: Dr. Stephen Chaney 

There is a well-known health disparity in clinical studies related to health. For years most of the studies have been done by men for men. Women have been assumed to experience the same benefits and risks from diet choices as men. But that hasn’t always proven to be true.

The Mediterranean diet is no exception. For example, it has garnered a reputation of reducing heart disease risk for both men and women.

However, most studies on the Mediterranean diet have included primarily male participants or did not report sex specific differences in outcomes.

And the few studies that reported sex specific outcomes have been inconsistent.

  • Some studies have found that men and women benefitted equally from the Mediterranean diet.
  • Other studies have reported that men benefitted more than women.

However, these were all small studies. No meta-analyses have been reported that focused on the heart benefits of the Mediterranean diet for women.

The study (A Pant et al., Heart; 109: 1208-1215, 2023) I will describe today was designed to fill that gap.

How Was The Study Done?

clinical studyThe investigators started by screening the literature to find studies that:

  • Measured adherence to the Mediterranean diet using the original MDS (Mediterranean Diet Score) or more recent modifications of the MDS.
  • Included women ≥18 years without previous diagnosis of clinical or subclinical heart disease.
  • Performed the study with only women participants or organized their data so that the data pertaining to women could be extracted from the study.

The investigators then performed a meta-analysis on data from 722,495 women in 16 studies published between 2006 and 2021 that met these criteria. These studies followed the women for an average of 12.5 years. The studies were primarily conducted in the United States and Europe.

The individual studies divided participants into either quintiles or quartiles and compared participants with the highest adherence to the Mediterranean diet to those with the lowest adherence.

  • The primary outcomes measured were total mortality and the incidence of CVD, cardiovascular disease (defined as including CHD (coronary heart disease), myocardial infarction (heart attack), stroke, heart failure, and cardiovascular death).
  • The secondary outcomes measured were stroke and CHD, coronary heart disease (heart disease caused by atherosclerotic plaque build up in the coronary arteries).

Is The Mediterranean Diet Healthy For Women?

Mediterranean Diet FoodsWhen comparing the highest to the lowest adherence to the Mediterranean diet:

  • The incidence of CVD (cardiovascular disease) was reduced by 24%.
  • Total mortality during the ~12.5-year follow-up was reduced by 23%.
  • The incidence of CHD (coronary heart disease) was reduced by 25%.
  • The risk of stroke was reduced by 13%, but that risk reduction was not statistically significant.
    • The risk reduction for both CVD and total mortality was similar to that previously reported for men.
    • Risk reduction for CVD was slightly higher for women of European descent (24%) than for women of non-European descent (21%). The later category included women of Asian, Native-Hawaiian, and African – American descent.

The authors concluded, “This study supports a beneficial effect of the Mediterranean diet on the primary prevention of CVD and death in women and is an important step in enabling sex-specific guidelines.”

I would add that the data from women of non-European decent suggests that genetic background and/or ethnicity may influence the effectiveness of the Mediterranean diet at reducing heart disease risk, but this effect appears to be small.

What Does This Mean For You?

The results of this study are not unexpected. But that doesn’t mean that studies with women are not valuable. There have been several examples in recent years where health or medical advice based on studies with men needed to be modified for females once the studies were repeated with women.

Before covering what this study means for you, I should point out that while women often fear breast cancer most, heart disease is their number one killer, as the graph on the left shows. In fact, a woman’s risk of dying from coronary heart disease is 6 times greater than her risk of dying from breast cancer.

This study shows that following a Mediterranean–style diet lowers their risk of developing and dying from heart disease. But the Mediterranean diet is not alone in providing these health benefits. It is simply a whole food, primarily plant-based diet that reflects the food preferences of the Mediterranean region.

The DASH diet, which reflects the food preferences of Americans, and the Nordic diet, which reflects the food preferences of the Scandinavian countries, are equally heart healthy. In fact, any whole food, primarily plant-based diet will reduce the risk of heart disease. You should choose the one that best fits your food preferences and lifestyle.

Of course, diet is just part of a holistic approach for reducing heart disease risk. Other important risk reduction strategies include:

  • Don’t smoke.
  • Exercise and maintain a healthy weight.
  • Manage stress.
  • Avoid or limit alcohol.
  • Know your numbers (cholesterol, triglycerides, and blood pressure, for example).
  • Manage other health conditions that increase the risk of heart disease (high blood pressure, diabetes, and high cholesterol, for example).

The Bottom Line

Most studies on the heart health benefits of the Mediterranean diet have been done with men or have not analyzed the data from men and women separately. A recent meta-analysis combining data from 16 studies with 722,495 women showed that the Mediterranean diet was just as heart healthy for women as it was for men.

The authors concluded, “This study supports a beneficial effect of the Mediterranean diet on the primary prevention of CVD and death in women and is an important step in enabling sex-specific guidelines.”

For more details on this study and information on other diets that are heart healthy, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

_____________________________________________________________________________My My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 _____________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Are Calcium Supplements Heart Healthy?

by

Should You Follow Your Doctor’s Advice About Calcium Supplementation?

Author: Dr. Stephen Chaney

Heart ConfusionAre calcium supplements good for your heart or bad for your heart? If you don’t know the answer to that question, don’t feel badly. You have every right to be confused. Some studies say that calcium supplements increase heart disease risk while others say they decrease heart disease risk. The headlines have veered between “killer calcium” and “beneficial calcium”.

The trend appears to be moving in a positive direction. In recent years most of the studies have suggested that calcium supplements either decrease heart disease risk or have no effect on heart disease risk.

However, the medical profession has been slow to take note of this trend. Most medical societies and health professionals have focused on earlier studies and are still recommending that their patients get calcium from food rather than from supplements. I will talk more about that recommendation below.

With this context in mind, this week I will review and discuss the results from the latest study (MG Sim et al, Heart, Lung and Circulation, 32: 1230-1239, 2023) on the effect of calcium supplementation on heart disease risk.

How Was This Study Done?

Clinical StudyThe authors of this study performed a meta-analysis of 12 double-blinded randomized clinical trials with 87,899 participants comparing the effect of a calcium supplement versus a placebo on heart disease outcomes (heart attack, stroke, heart failure, cardiovascular mortality, and all-cause mortality).

The studies included in this analysis:

  • Used calcium doses from 500 mg/day to 2,000 mg/day.
  • Used supplements with calcium coming from a variety of sources (calcium carbonate, calcium citrate, calcium gluconolactate, and tricalcium phosphate).
  • Ranged from 18 months to almost 12 years in length.
  • Were performed with population groups from a wide range of countries (United States, England, France, Australia, New Zealand, European Union, Denmark, and Thailand).
  • Included calcium supplements with and without vitamin D.
  • Were primarily (86% of participants) conducted with post-menopausal women. One small study (0.3% of participants) was conducted with non-osteoporotic men. The rest were conducted with mixed populations (men and women) diagnosed with colorectal adenoma.

Are Calcium Supplements Heart Healthy?

calcium supplementsThis is the largest meta-analysis performed to date of double-blind, placebo-controlled randomized clinical trials on the effect of calcium supplementation versus a placebo on heart disease outcomes. This study found no effect of calcium supplementation on:

  • Heart attack.
  • Stroke
  • Heart failure.
  • Cardiovascular mortality.
  • All-cause mortality.

This study also evaluated potential confounding variables and found no effect of calcium supplementation on heart disease risk for:

  • Calcium supplements with and without vitamin D.
  • Dosage of calcium in the supplements (The dosage ranged from 500 mg/day to 2,000 mg/day).
  • Females (I suspect the number of males in this study was too small to come to a statistically significant conclusion).
  • Duration of calcium supplementation ≤ 5 years (The shortest duration of calcium supplementation in these studies was 18 months).
  • Different geographical regions.

However, this meta-analysis reported considerable variation between studies included in the analysis. Simply put,

  • Some studies showed an increase in heart disease risk.
  • Some studies showed a decrease in heart disease risk.
  • Some studies showed no effect on heart disease risk.

What this analysis showed was that when you combine all the studies, the aggregated data is consistent with calcium supplementation having no effect on heart disease risk.

The authors concluded, “Calcium supplementation was not associated with myocardial infraction [heart attack], stroke, heart failure, and cardiovascular/all-cause mortality. Further studies are required to examine and understand these associations.

Should You Follow Your Doctor’s Advice About Calcium Supplementation?

Doctor With PatientAs I said above, most medical societies and health professionals have focused on earlier studies and are still recommending that their patients get calcium from food rather than from supplements. That may be the advice you are getting from your doctor.

Before you assume your doctor isn’t keeping up with the latest science and ignore his or her advice, we should ask why they are giving that advice. The top three reasons most medical societies give for recommending dietary sources of calcium are:

1) Some studies do show an increased risk of heart disease associated with calcium supplementation. The prime directive for health professionals is to do no harm. Yes, the average of all studies shows no effect of calcium supplementation on heart disease risk. But what if the studies showing increased risk are true for some of their patients? Those patients could be harmed. 

Are you someone who might be at increased risk for heart disease if you take calcium supplements. The short answer is we don’t know because previous studies have not asked the right questions. 

In my opinion, it is time to pause additional studies and meta-analyses on calcium supplementation and heart health until we have gone over existing studies with a fine-tooth comb to figure out why the results differ so wildly. For example, we need to ask whether the effect of calcium supplements on heart disease risk is influenced by things like:

    • Age or ethnicity of participants.
    • Other preexisting health conditions.
    • Other lifestyle factors (exercise is probably the most important, but others may be involved as well).
    • Diet context. For example, we already know that the effect of eggs and dairy on heart health is influenced by diet context. [I have covered this for eggs in a previous issue of “Health Tips From the Professor”.]
    • Other unanticipated variables.

Only when we have identified variables that might influence the effect of calcium supplements on heart disease risk, will the scientific community be able to design studies to identify the population groups who might be adversely affected by calcium supplementation.

This would allow health professionals to make informed decisions about which of their patients should avoid calcium supplementation and which of their patients would benefit from calcium supplementation. 

2) We really don’t need the recommended RDAs for calcium to build strong bones. The Healthy Bonerecommended RDAs for calcium are 1,000 mg/day for adults 19-50, 1,000 mg/day for men and 1,200 mg/day for women 51-70, and 1,200 mg/day for both men and women over 70. But do we really need that amount of calcium to build healthy bones? 

I have discussed this topic in detail in a previous issue of “Health Tips From the Professor”. Here are the key points:

    • The current RDAs are based on calcium needs for people consuming the typical American diet and following the typical American lifestyle. If that is you, the current RDAs probably apply.
    • However, strong bones are absolutely dependent on three things, adequate calcium, adequate vitamin D, and adequate weight-bearing exercise. Most recent studies of calcium supplementation and bone density include adequate vitamin D, but almost none of them include exercise. Previous studies have been inadequate.
    • The best calcium supplements contain certain nutrients besides vitamin D that optimize bone formation. I have listed those nutrients in the article cited above.
    • Our ability to use calcium to build strong bones is dependent on diet (something I call a bone-healthy diet) and lifestyle (something I call a bone-healthy lifestyle).
    • For more information on each of these points, read the article I referenced above.

In short, I agree that the current calcium RDAs may be too high for individuals consuming a bone-healthy diet and following a bone-healthy lifestyle. But the current calcium RDAs are likely accurate for people consuming the typical American diet and following the typical American lifestyle.

    • While we do not have a calcium RDA for populations following a bone healthy diet lifestyle, some studies suggest that 700-800 mg of calcium/day may be sufficient for this group.

3) Calcium from supplements is absorbed faster and gives higher blood level spikes than calcium from foods. That could be a problem because high blood levels of calcium are associated with calcification of our arteries, which is associated with increased heart disease risk. 

This is a theoretical concern, because high blood calcium levels from supplementation are transitory, while it is continuous high blood calcium levels that are associated with calcification of our arteries.

However, it is a plausible concern because most supplement companies design their calcium supplements based on how quickly they get calcium into the bloodstream rather than how effectively the calcium is utilized for bone formation. Here are my recommendations:

    • Choose a calcium supplement that provides RDA levels of vitamin D plus other nutrients shown to support strong bone formation.
    • Choose a calcium supplement supported by clinical studies showing it is effectively utilized for bone formation.

4) We should be getting our calcium from foods rather than supplements. dairy foods

While it is always easy for doctors to recommend that we get our nutrients from food rather than supplements, they need to ask whether we are getting those nutrients from our diet. For calcium the data are particularly sobering.

    • The average American gets around 740 mg of calcium/day from their diet. That is probably enough for the small percentage of Americans following a bone healthy diet and lifestyle. But it is 260-460 mg short of the 1,000-1,200 mg/day recommended for older adults with the typical American diet and lifestyle.
      • And for the average American, around 70% of their calcium intake comes from dairy foods.

       

      • So, Americans who are following a typical American diet and lifestyle and are restricting dairy may require 800-1,000 mg/day of supplemental calcium unless they carefully plan their diets to optimize calcium intake.

       

      • Finally, vegans average about 550 mg/day from their diet. That might be borderline even if they were following a bone healthy lifestyle.
    • In short, we cannot assume our diet will provide enough calcium for strong bones unless we include dairy foods and/or plan our diet very carefully. Some degree of supplementation may be necessary.

How Much Calcium Do You Need?

Questioning Woman

I have covered a lot of territory in this article, so let me summarize the four concerns of the medical community and answer your most important question, “Should you take calcium supplements?”

1) Calcium supplements may increase the risk of heart disease for some people.

That is true, but we have no idea at present who is at increased risk and who isn’t. So, we should minimize our risk by taking the precautions I describe below.

2) We don’t need RDA levels of calcium to build strong bones. That is probably true if you are one of the few people who follows a bone healthy diet and lifestyle, but it isn’t true if you follow the typical American diet and lifestyle.

  • The current RDAs of 1,000 – 1,200 mg/day are a good guideline for how much calcium you need if you follow the typical American diet and lifestyle.
  • If you a one of the few people who follow a bone healthy diet and lifestyle (For what that involves, read this article) you may only need 700-800 mg/day. But we don’t have clinical studies that can tell us what the actual RDA for calcium should be under those circumstances.

3) Calcium from supplements is absorbed faster and gives higher blood calcium spikes than calcium from foods. You may remember that the theoretical concern is that even short-term spikes of high blood calcium may lead to calcification of your arteries, which increases your risk of heart disease. So, the important question becomes, “What can we do to minimize these spikes in blood calcium levels?”

  • We should avoid calcium supplements that brag about how quickly and efficiently the calcium is absorbed. That could lead to calcium spikes. Instead, we should look for calcium supplements that are backed by clinical studies showing they are efficiently utilized for bone formation.
  • We should look for calcium supplements that include RDA levels of vitamin D and other nutrients that optimize bone formation. You will find more information on that in the same article I referenced above.
  • Some experts recommend that calcium supplements be taken between meals. But it is probably better to take them with meals because foods will likely slow the rate at which calcium is absorbed and reduce calcium spikes in the blood.
  • We are told to limit calcium supplements to less than 500 mg at any one time because calcium absorption becomes inefficient at higher doses. It might be even better to limit calcium to 250 mg or less at a time to reduce calcium spikes in the blood.

4) We should get calcium from foods rather than supplements.

  • Many Americans do not get enough calcium from diet alone, especially if they avoid dairy foods. So, some degree of calcium supplementation may be necessary. I have given some guidelines depending on your diet and lifestyle above.
  • The amount of supplemental calcium needed is relatively small. I do not recommend exceeding the RDA unless directed to by your health professional.

The Bottom Line 

Some studies say that calcium supplements increase heart disease risk while others say they decrease heart disease risk. The headlines veer between “killer calcium” and “beneficial calcium”.

The trend appears to be moving in a positive direction. In recent years most of the studies have suggested that calcium supplements either decrease heart disease risk or have no effect on heart disease risk.

However, the medical profession has been slow to take note of this trend. Most medical societies and health professionals have focused on earlier studies and are still recommending that their patients get calcium from food rather than from supplements.

A recent meta-analysis of 12 double-blinded randomized clinical trials with 87,899 participants comparing the effect of a calcium supplement versus a placebo on heart disease outcomes has just been published. This study found no effect of calcium supplementation on:

  • Heart attack.
  • Stroke.
  • Heart failure.
  • Cardiovascular mortality.
  • All-cause mortality.

The authors of the study concluded, “Calcium supplementation was not associated with myocardial infraction [heart attack], stroke, heart failure, and cardiovascular/all-cause mortality.

For more details and advice on whether you should follow your doctor’s recommendations for calcium supplementation read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 _____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

____________________________________________________________________

About The Author

Dr. Steve ChaneyDr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

 

What Can Twins Tell Us About Diet?

by

What Are The Pros And Cons Of Twin Studies? 

Author: Dr. Stephen Chaney 

Why is the advice on healthy diets so confusing? One blog claims the vegan diet is best. Another says it is the keto diet is best. The Mediterranean diet is popular, but other experts claim the DASH or MIND diet might be better. Blogs champion diets ranging from the familiar to downright weird.

If you try to keep up with the science, it seems like the science is constantly changing. Each week you see headlines saying the latest study shows diet “X” is best – and “X” keeps changing. Why is that? Why do studies on healthy diets keep coming up with conflicting conclusions?

I have discussed the strengths and weaknesses of clinical studies and why they provide conflicting results in detail in previous issues of “Health Tips From the Professor”. However, one factor I have not discussed in detail is the effect of genetics on how we utilize foods, something called nutrigenomics.

Simply put, we are all genetically different. The way we utilize foods is different. The effect that foods have on our bodies is different. I have touched on that briefly in a previous article discussing individual difference in blood sugar response to various foods. But that is just one of many examples.

We do not yet know enough about gene-nutrient interactions to use genomic data to accurately predict which diets are best. Again, I have covered that topic in a previous issue of “Health Tips From the Professor”. However, we do know that genetic differences have a big influence on which diet is best for us. And most clinical studies on diets do not even attempt to take genetic differences into account.

That is where twin studies come in. Identical twins (monozygotic twins) have an identical genetic makeup and usually have an identical environment until they become adults. So, when I saw an identical twin study (MJ Landry et al, JAMA Network Open, 6(11):e2344457, 2023) comparing a vegan diet (only plant foods) with an omnivorous diet (both animal and plant foods), I wanted to review it and share it with you.

How Was The Study Done? 

Clinical StudyIdentical twins were recruited from the Stanford Twin Registry. Twenty-two identical twin pairs were chosen for this study. Their characteristics were average age = 40, BMI = 26% (moderately overweight), sex = 77% female, ethnicity = 73% white, followed by an approximately equal representation of Asian, black, multiracial, and Pacific Islander.

One unanticipated characteristic of this group of twins was that 70% of them still lived together and cooked together, so their environment was also very similar.

One twin of each pair was put on a healthy vegan diet and the other on a healthy omnivorous diet for 8 weeks. Both diets were designed by dietitians. The diets emphasized fruits, vegetables, and whole grains while limiting added sugars and refined grains.

Both diets were healthier than the diets the twins were eating prior to the study. Finally, the participants were not told how much to eat, and were not instructed to lose weight.

For the first four weeks the participants were provided with all their meals by a nationwide food delivery company. The participants were also provided with training on purchasing and preparing healthy foods for their diet. This prepared them for the last 4 weeks of the study in which they purchased and prepared their own meals.

Participants visited the Stanford Clinical and Translational Science Research Unit at the beginning of the study and at the end of weeks 4 and 8 for weight measurement and a fasting blood draw.

Adherence to the diets was measured by a series of unannounced interviews to administer a 24-hour dietary recall questionnaire. These were scheduled for the weeks they visited the clinic.

What Can Twins Tell Us About Diet? 

TwinsEven though the sample size was small, there were three statistically significant results.

  • LDL-cholesterol was reduced by 12% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet.
  • The fasting insulin level was reduced by 21% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet. This suggests the twin on the vegan diet was experiencing improved blood sugar control after just 8 weeks.
  • The twin on the vegan diet lost 4 pounds in 8 weeks, while weight remained the same for the twin on the omnivorous diet. This occurred even though neither twin was instructed to eat less nor to lose weight. It is most likely a consequence of the lower caloric density of the vegan diet (See my discussion of caloric density in last week’s issue of “Health Tips From the Professor”.
  • The changes in LDL-cholesterol and fasting insulin were remarkable because none of the twins in this study had elevated LDL-cholesterol or problems with blood sugar control at the beginning of the study.

The authors of this study concluded, “In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.”

[Let me decipher the term cardiometabolic for you. The decrease in LDL-cholesterol is associated with heart health – the cardio portion of the term. The decrease in fasting insulin is associated with decreased risk of diabetes. Since diabetes is considered a metabolic disease, this is the metabolic portion of the term.]

Were There Any Downsides To The Vegan Diet? 

thumbs down symbolThis study also highlighted two well-known limitations of vegan diets.

  • Although the differences were not statistically significant, the authors expressed concern that vitamin B12 intake was less for twins on the vegan diet than twins on the omnivorous diet even though the vegan diet was designed by dietitians.

The authors noted that B12 deficiency among vegans is well known, and said, “Long-term vegans are typically encouraged to take a cyanocobalamin (vitamin B12) supplement.

  • Although both groups had excellent adherence to their assigned diets, those assigned to the vegan diet expressed a lower satisfaction with the diet, which suggests long-term adherence to the diet after the study ended was unlikely.

The authors said, “Although our findings suggest that vegan diets offer a protective cardiometabolic advantage compared with a healthy omnivorous diet, excluding all meats and/or dairy products may not be necessary because research suggests that cardiometabolic benefits can be achieved with modest reduction in animal foods and increases in healthy plant-based foods compared with typical diets.”

“We believe that lower dietary satisfaction in the vegan group may have been attributable to the strictness of the vegan diet…Some people may find a less restrictive diet preferable for LDL-cholesterol-lowering effects.”

I concur.

What Are The Pros And Cons Of Twin Studies? 

pros and consThe Pros are obvious. Most dietary studies cannot take genetic differences into account and have difficulty accounting for environmental differences. In this study genetics was identical for each twin pair and their environment was very similar. It offers a unique advantage over other studies.

But the strength of this study is also its greatest weakness. Because the general population is genetically and environmentally diverse, it is difficult to extrapolate the results to the general population.

If this were the only study to show cardiometabolic benefits of a plant-based diet, it would simply be an interesting observation.

  • But there are several studies showing that the vegan diet is associated with lower weight and reduced risk of heart disease and diabetes.
  • And there are dozens of studies showing that primarily plant-based omnivorous diets reduce the risk of heart disease and diabetes.

This study is fully consistent with those studies.

The Bottom Line 

A recent study put identical twins on either a healthy vegan diet (only plant foods) or a healthy omnivorous diet (both animal and plant foods) for 8 weeks. At the end of 8 weeks:

  • LDL-cholesterol was reduced by 12% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet.
  • The fasting insulin level was reduced by 21% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet. This suggests the twin on the vegan diet was experiencing improved blood sugar control after just 8 weeks.
  • The twin on the vegan diet lost 4 pounds in 8 weeks, while weight remained the same for the twin on the omnivorous diet. This occurred even though neither twin was instructed to eat less or to lose weight. It is most likely a consequence of the lower caloric density of the vegan diet.
  • The changes in LDL-cholesterol and fasting insulin were remarkable because none of the twins in this study had elevated LDL-cholesterol or problems with blood sugar control at the beginning of the study.

The authors of this study concluded, “In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.”

For more information on the pros and cons of this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 _____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

 About The Author

Dr. Steve ChaneyDr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

For the past 35 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Which Diets Are Heart Healthy?

by

Which Diet Is Best For You?

Author: Dr. Stephen Chaney 

strong heartThe top 3 claims the advocates of every popular diet make are:

  • It will help you lose weight.
  • It reduces your risk of diabetes.
  • It reduces your risk of heart disease.

The truth is any restrictive diet helps you lose weight. And when you lose weight, you improve blood sugar control. Which, of course, reduces your risk of developing diabetes.

But what about heart disease? Which diets are heart healthy? When it comes to heart disease the claims of diet advocates are often misleading. That’s because the studies these advocates use to support their claims are often poor quality studies. Many of these studies:

  • Look at markers of heart disease risk rather than heart disease outcomes. Markers like LDL cholesterol, triglycerides, c-reactive protein, etc. are only able to predict possible heart disease outcomes. To really know which diets are heart healthy you have to measure actual heart disease outcomes such as heart attacks, stroke, and cardiovascular deaths.
  • Are too short to provide meaningful results. Many of these studies last only a few weeks. You need much longer to measure heart disease outcomes.
  • Are too small to provide statistically significant results. You need thousands of subjects to be sure the results you are seeing are statistically significant.
  • Have not been confirmed by other studies. The Dr. Strangeloves of the world like to “cherry pick” the studies that support the effectiveness of their favorite diet. Objective scientists know that any individual study can be wrong. So, they look for consensus conclusions from multiple studies.

A recent study (G Karam et al, British Medical Journal, 380: e072003, 2023) avoided all those pitfalls. The investigators conducted a meta-analysis of 40 high-quality clinical studies with 35,548 participants to answer the question, “Which diets are heart healthy?”

How Was The Study Done?

Clinical StudyThe authors started by searching all major databases of clinical studies for studies published on the effect of diets on heart disease outcomes through September 2021.

They then performed a meta-analysis of the data from all studies that:

  • Compared the effect of a particular diet to minimal dietary intervention (defined as not receiving any advice or receiving dietary information such as brochures or brief advice from their clinician with little or no follow-up).
  • Looked at heart disease outcomes such as all cause mortality, cardiovascular mortality, non-fatal heart attacks, stroke, and others.
  • Lasted for at least 9 months (average duration = 3 years).
  • Were high-quality studies.

Using these criteria:

  • They identified 40 studies with 35,548 participants for inclusion in their meta-analysis.
    • From those 40 studies, they identified 7 diet types that met their inclusion criteria (low fat (18 studies), Mediterranean (12 studies), very low fat (6 studies), modified fat (substituting healthy fats for unhealthy fats rather than decreasing fats, 4 studies), combined low fat and low sodium (3 studies), Ornish (3 studies), Pritikin (1 study).

One weakness of meta-analyses is that the design of the studies included in the meta-analysis is often different. Sometimes they don’t fit together well. So, while the individual studies are high-quality, a combination of all the studies can lead to a conclusion that is low quality or moderate quality.

Finally, the data were corrected for confounding factors such as obesity, exercise, smoking, and medication use.

Which Diets Are Heart Healthy?

Now that you understand the study design, we are ready to answer the question, “Which diets are heart healthy?” Here is what this study found:

Compared to minimal intervention,

  • The Mediterranean diet decreased all cause mortality by 28%, cardiovascular mortality by 45%, stroke by 35%, and non-fatal heart attacks by 52%.
  • Low fat diets decreased all cause mortality by 16% and non-fatal heart attacks by 23%. The effect of low fat diets on cardiovascular mortality and stroke was not statistically significant in this meta-analysis.
    • For both the Mediterranean and low fat diets, the heart health benefits were significantly better for patients who were at high risk of heart disease upon entry into the study.
    • The evidence supporting the heart health benefits for both diets was considered moderate quality evidence for this meta-analysis. [Remember that the quality of any conclusion in a meta-analysis is based on both the quality of evidence of the individual studies plus how well the studies fit together in the meta-analysis.]
  • While the percentage of risk reduction appears to be different for the Mediterranean and low fat diets, the effect of the two diets on heart health was not considered significantly different in this study.
  • The other 5 diets provided little, or no benefit, compared to the minimal intervention control based on low to moderate quality evidence.

The authors concluded, “This network meta-analysis found that Mediterranean and low fat dietary programs probably reduce the risk of mortality and non-fatal myocardial infarction [heart attacks] in people at increased cardiovascular risk. Mediterranean dietary programs are also likely to reduce the risk of stroke. Generally, other dietary programs were not superior to minimal intervention.”

Which Diet Is Best For You?

confusionThe fact that this study found both the Mediterranean diet and low fat diets to be heart healthy is not surprising. Numerous individual studies have found these diets to be heart healthy. So, it is not surprising when the individual studies were combined in a meta-analysis, the meta-analysis also concluded they were heart healthy. However, there are two important points I would like to make.

  • The diets used in these studies were designed by trained dietitians. That means the low fat studies did not use Big Food, Inc’s version of the low fat diet in which fatty foods are replaced with highly processed foods. In these studies, fatty foods were most likely replaced with whole or minimally processed foods from all 5 food groups.
  • The Mediterranean diet is probably the most studied of current popular diets. From these studies we know the Mediterranean diet improves brain health, gut health, and reduces cancer risk.

As for the other 5 diets (very low fat, modified fat, low fat and low sodium, Ornish, and Pritikin), I would say the jury is out. There is some evidence that these diets may be heart healthy. But very few of these studies were good enough to be included in this meta-analysis. Clearly, more high-quality studies are needed.

Finally, you might be wondering why other popular diets such as paleo, low carb, and very low carb (Atkins, keto, and others) were left out of this analysis. All I can say is that it wasn’t by design.

The authors did not select the 7 diets described in this study and then search for studies testing their effectiveness. They searched for all studies describing the effect of diets on heart health. Once they identified 40 high-quality studies, they grouped the diets into 7 diet categories.

I can only conclude there were no high-quality studies of paleo, low carb, or very low carb diets that met the criteria for inclusion in this meta-analysis. The criteria were:

  • The effect of diet on heart health must be compared to a control group that received no or minimal dietary advice.
  • The study must measure heart disease outcomes such as all cause mortality, cardiovascular mortality, non-fatal heart attacks, and stroke.
  • The study must last at least 9 months.
  • The study must be high-quality.

Until these kinds of studies are done, we have no idea whether these diets are heart healthy or not.

So, what’s the takeaway for you? Which diet is best for you? Both low fat diets and the Mediterranean diet are heart healthy provided the low fat diet consists of primarily whole or minimally processed foods. Which of these two diets is best for you depends on your food preferences.

The Bottom Line 

Many of you may have been warned by your doctor that your heart health is not what it should be. Others may be concerned because you have a family history of heart disease. You want to know which diets are heart healthy.

Fortunately, a recent study answered that question. The authors performed a meta-analysis of 40 high-quality studies that compared the effect of various diets with the effect of minimal dietary intervention (doctors’ advice or diet brochure) on heart disease outcomes.

From this study they concluded that both low fat diets and the Mediterranean diet probably reduce mortality and the risk of non-fatal heart attacks, and that the Mediterranean diet likely reduces stroke risk.

Other diets studied had no significant effect on heart health in this study. That does not necessarily mean they are ineffective. But it does mean that more high-quality studies are needed before we can evaluate their effect on heart health.

So, what’s the bottom line for you? Both low fat diets and the Mediterranean diet are heart healthy provided the low fat diet consists of primarily whole or minimally processed foods Which of these two diets is best for you depends on your food preferences.

For more information on this study, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

___________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

Health Tips From The Professor