Heart Attack

Are Omega-3 Supplements Safe?

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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?

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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.

Do Omega-3s Improve Recovery From A Heart Attack?

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Where Do We Go From Here? 

Author: Dr. Stephen Chaney 

Omega-3s And Heart DiseaseDespite years of controversy, the benefits of omega-3s remain an active area of research. Over the next few weeks, I will review several groundbreaking omega-3 studies. This week I will focus on omega-3s and heart health.

I don’t need to tell you that the effect of omega-3s on heart health is controversial. One month a new study is published showing an amazing health benefit from omega-3 supplementation. A month or two later another study comes up empty. It finds no benefit from omega-3 supplementation.

That leads to confusion. On one hand you have websites and blogs claiming that omega-3s are a magic elixir that will cure all your ills. On the other hand, there are the naysayers, including many health professionals, claiming that omega-3 supplements are worthless.

I have discussed the reasons for the conflicting results from omega-3 clinical studies in previous issues of “Health Tips From the Professor”. You can go to https://www.chaneyhealth.com/healthtips/ and put omega-3s in the search box to read some of these articles.

Or if you prefer, I have also put together a digital download I call “The Omega-3 Pendulum” which briefly summarizes all my previous articles. It’s available on my Chaney Health School Teachable website.

Today I will discuss a study (B Bernhard et al, International Journal of Cardiology, 399; 131698, 2024) that asks whether 6 months of high dose omega-3 supplementation following a heart attack reduced the risk of major cardiovascular events over the next 6.6 years.

You might be wondering why the study didn’t just look at the effect of continuous omega-3 supplementation for 6 years following a heart attack. There are two very good reasons for the design of the current study.

1) The investigators wanted to do a double blind, placebo controlled clinical trial, the gold standard for clinical studies. However, that kind of study is impractical for a multi-year clinical trial. It would be prohibitively expensive, and patient compliance would be a big problem for a study that long.

2) The months immediately after a heart attack are critical in determining the long-term recovery of that patient. There is often a period of massive inflammation following a heart attack. And that can lead to further damage to the heart and reclosing of the arteries leading to the heart, both of which increase the risk of future adverse cardiac events.

Previous studies have shown that high dose omega-3s immediately following a heart attack can reduce inflammation and damage to the heart. However, those studies did not determine whether the cardioprotective effect of omega-3 supplementation immediately after a heart attack lead to improved long-term outcomes, something this study was designed to determine.

How Was The Study Done?

clinical studyThe investigators enrolled 358 patients who had suffered a heart attack from three Boston area medical centers between June 2008 and August 2012.

The patient demographics were:

  • Gender = 70% female.
  • Average age = 59
  • Average BMI = 29 (borderline obese).
  • Patients with high blood pressure = 64%
  • Patients with diabetes = 25%.

The patients were divided into two groups. The first group received capsules providing 4 gm/day of EPA, DHA, and other naturally occurring omega-3 fatty acids. The other group received a placebo containing corn oil. This was a double-blind study. Neither the patients nor the investigators knew which patients received the omega-3 fatty acids and which ones received the placebo.

The patients were instructed to take their assigned capsules daily for 6 months. At the beginning of the study, blood samples were withdrawn to determine the percentage of omega-3s in the fatty acid content of their red cell membranes (something called omega-3 index). Patients were also tested for insulin resistance and given a complete cardiovascular workup. This was repeated at the end of the 6-month study.

[Note: Previous studies have shown that an omega-3 index of 4% or lower is associated with high risk of heart disease, and an omega-3 index of 8% or above is associated with a low risk of heart disease.]

At 2-month intervals the patients were contacted by staff using a scripted interview to determine compliance with the protocol and their cardiovascular health. Once the 6 months of omega-3 supplementation was completed, the patients were followed for an additional 6.6 years. They were contacted every 6 months for the first 3 years and yearly between 3 years and 6 years.

The investigators quantified the number of major cardiac events (defined as recurrent heart attacks, the necessity for recurrent coronary artery bypass grafts, hospitalizations for heart failure, and all-cause deaths) for each patient during the 6.6-year follow-up period.

Patients in both groups were treated according to current “standard of care” protocols which consisted of diet and exercise advice and 5-6 drugs to reduce future cardiovascular events.

Do Omega-3s Improve Recovery From A Heart Attack?

heart attacksWhen the investigators looked at the incidence of adverse cardiac events during the 6.6-year follow-up period, there were three significant findings from this study.

1) There were no adverse effects during the 6-month supplementation period with 4 gm/day of omega-3s. This is significant because a previous study with 4 gm/day of high purity EPA had reported some adverse effects which had led some critics to warn that omega-3 supplementation was dangerous. More study is needed, but my hypothesis is that this study did not have side effects because it used a mixture of all naturally occurring omega-3s rather than high purity EPA only. 

However, this could also have been because of the way patients were screened before entering this study. I will discuss this in more detail below.

2) When the investigators simply compared the omega-3 group with the placebo group there was no difference in cardiovascular outcomes between the two groups. This may have been because this study faced significant “headwinds” that made it difficult show any benefit from supplementation. I call them “headwinds” rather than design flaws because they were unavoidable. 

    • It would be unethical to deny the standard of care to any patient who has just had a heart attack. That means that every patient in a study like this will be on multiple drugs that duplicate the beneficial effects of omega-3 fatty acids – including lowering blood pressure, lowering triglycerides, reducing inflammation, and reducing plaque buildup and blood clot formation in the coronary arteries.

That means that this study, and studies like it, cannot determine whether omega-3 fatty acids improve recovery from a heart attack. They can only ask whether omega-3 fatty acids have any additional benefit for patients on multiple drugs that duplicate many of the effects of omega-3 fatty acids. That significantly reduces the risk of a positive outcome.

    • As I mentioned above, it would have been impractical to continue providing omega-3 supplements and placebos during the 6.6-year follow-up.

And the study was blinded, meaning that the investigators did not know which patients got the omega-3s and which patients got the placebo. That meant the investigators could not advise the omega-3 supplement users to continue omega-3 supplementation during the follow-up period.

Consequently, the study could only ask if 6 months of high-dose omega-3 supplementation had a measurable benefit 6.6 years later. I, for one, would be more interested in knowing whether lower dose omega-3 supplementation continued for the duration of this study reduced the risk of major coronary events.good news

3) When the investigators compared patients who achieved a significant increase in their omega-3 index during the 6-month supplementation period with those who didn’t, they found a significant benefit of omega-3 supplementation.

This was perhaps the most significant finding from this study.  

If the investigators had stopped by simply comparing omega-3 users to the placebo, this would have been just another negative study. We would be wondering why it did not show any benefit of omega-3 fatty acid supplementation.

However, these investigators were experts on the omega-3 index. They knew that there was considerable individual variability in the efficiency of omega-3 uptake and incorporation into cell membranes. In short, they knew that not everyone taking a particular dose of omega-3s will achieve the same omega-3 index.

And that is exactly what they saw in this study. All the patients in the 6-month omega-3 group experienced an increase in omega-3 index, but there was considerable variability in how much the omega-3 index increased over 6 months.

So, the investigators divided the omega-3 group into two subgroups – ones whose omega-3 index increased by ≥ 5 percentage points (sufficient to move those patients from high risk of heart disease to low risk) and ones whose omega-3 index increased by less than 5 percentage points.

When the investigators compared patients with ≥ 5% increase in omega-3 index to those with <5% increase in omega-3 index:

  • Those with an increase in omega-3 index of ≥ 5% had a 2.9% annual risk of suffering major adverse cardiac events compared to a 7.1% annual risk for those with an increase of <5%.
  • That’s a risk reduction of almost 60%, and it was highly significant.

The authors concluded, “In a long-term follow-up study, treatment with [high dose] omega-3s for 6 months following a heart attack did not reduce adverse cardiac events compared to placebo. However, those patients who were treated with omega-3s and achieved ≥ 5% rise in omega-3 index experienced a significant reduction of adverse cardiac events after a median follow-up period of 6.6 years…Additional studies are needed to confirm this association and may help identify who may benefit from omega-3 fatty acid treatment following a heart attack.”

What Does This Study Mean For You? 

Questioning WomanI should start by saying that I do not recommend 4 gm/day of omega-3 fatty acids following a heart attack without checking with your doctor first.

  • If you are on a blood thinning medication, the dose of either the medication or the omega-3 supplement may need to be reduced to prevent complications due to excess bleeding.
  • In addition, the investigators excluded patients from this study who might suffer adverse effects from omega-3 supplementation. This is a judgement only your doctor can make.

With that advice out of the way, the most important takeaway from this study is that uptake and utilization of omega-3 fatty acids varies from individual to individual.

The omega-3 index is a measure of how well any individual absorbs and utilizes dietary omega-3s. And this study shows that the omega-3 index is a much better predictor of heart health outcomes than the amount of omega-3 fatty acids a person consumes.

This is not surprising because multiple studies have shown that the omega-3 index correlates with heart health outcomes. It may also explain why many studies based on omega-3 intake only have failed to show a benefit of omega-3 supplementation.

Vitamin D supplementation is a similar story. There is also considerable variability in the uptake of vitamin D and conversion to its active form in the body. 25-hydroxy vitamin D levels in the blood are a marker for active vitamin D. For that reason, I have long recommended that you get your 25-hydroxy vitamin D level tested with your annual physical and, with your doctor’s help, base the dose of the vitamin D supplement you use on that test.

This study suggests that we may also want to request an omega-3 index test and use it to determine the amount of supplemental omega-3s we add to our diet.

Where Do We Go From Here?

Where Do We Go From HereThe idea that we need to use the omega-3 index to determine the effectiveness of the omega-3 supplement we use is novel. As the authors suggest, we need more studies to confirm this effect. There are already many studies showing a correlation of omega-3 index with heart health outcomes. But we need more double blind, placebo-controlled studies like this one.

More importantly, we need to understand what determines the efficiency of supplemental fatty acid utilization so we can predict and possibly improve omega-3 utilization. The authors suggested that certain genetic variants might affect the efficiency of omega-3 utilization. But the variability of omega-3 utilization could also be affected by:

  • Diet, especially the presence of other fats in the diet.
  • Metabolic differences due to obesity and diseases like diabetes.
  • Gender, ethnicity, and age.
  • Design of the omega-3 supplement.

We need much more research in these areas, so we can personalize and optimize omega-3 supplementation on an individual basis.

The Bottom Line 

A recent study asked whether high dose omega-3 supplementation for 6 months following a heart attack reduced major cardiac events during the next 6.6 years.

  • When they simply compared omega-3 supplementation with the placebo there was no effect of omega-3 supplementation on cardiac outcomes.
  • However, when they based their comparison on the omega-3 index (a measure of how efficiently the omega-3s were absorbed and incorporated into cell membranes), the group with the highest omega-3 index experienced a 60% reduction in adverse cardiac events over the next 6.6 years.

This is consistent with multiple studies showing that the omega-3 index correlates with heart health outcomes.

More importantly, this study shows there is significant individual variation in the efficiency of omega-3 absorption and utilization. It also suggests that recommendations for omega-3 supplementation should be based on the omega-3 index achieved rather than the dose or form of the omega-3 supplement.

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 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.

 

Which Diets Are Heart Healthy?

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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

Is Whole Fat Dairy Healthy?

by

Is It Dairy Or Diet?

Author: Dr. Stephen Chaney 

CheesesFor years we have been told to select low fat dairy foods. But recent headlines claim, “That’s nonsense. Whole fat dairy foods are healthy.” Are those headlines true?

In previous issues of “Health Tips From the Professor” I have kept you abreast of recent studies suggesting that whole fat dairy foods may not be as bad for us as we thought. I also cautioned you that the headlines may not have accurately represented the studies they described.

Headlines have to be simple. But truth is often more nuanced. If we believed the current headlines, we might be asking ourselves questions like, “Should we ditch the current health guidelines recommending low-fat dairy foods? Are foods like ice cream, sour cream, and cheddar cheese actually be good for us?

To answer these questions, I will look at the study (A Mente et al, European Heart Journal, 44, 2560-2579, 2023) behind the current headlines and put the study into perspective.

Spoiler alert: If I could summarize the study findings in two sentences, they would be, “Whole fat dairy can be part of a healthy diet. But can it be part of an unhealthy diet?”

Stay tuned. I will discuss the science behind that statement below.

How Was This Study Done?

clinical studyThis study started with data collected from the Prospective Urban Rural Epidemiology (PURE) study. The PURE study is an ongoing study correlating diet, lifestyle, and environmental effects on health outcomes. It has enrolled 166,762 individuals, age 35-70, from 21 low-, middle-, and high-income countries on 5 continents.

Habitual food intake was determined using country-specific food frequency questionnaires at the time participants joined the study. Participants (166,762) from the PURE study who had complete dietary information were included in this study and were followed for an average of 9.3 years.

Based on preliminary analysis of data from the PURE study, the authors developed their version of a healthy diet, which they call the PURE diet. Like most other healthy diets, the PURE diet emphasizes fruits, vegetables, legumes, nuts, and fish. However:

  • Based on studies suggesting that whole fat dairy foods can be part of a healthy diet, the PURE diet includes whole fat dairy foods.

This is different from most other healthy diet recommendations.

They went on to develop what they referred to as the PURE healthy diet score by:

  • Determining the median intake for each of the 6 food groups included in their PURE diet (fruits, vegetables, legumes, nuts, fish, and whole fat dairy).
  • Assigning each participant in the study a score of 0 or 1 depending on whether their intake for that food group was below or above the median intake.
  • Adding up the points. Since 6 food groups were included in the PURE diet, this means that each participant in the study was assigned a PURE diet score ranging from 0-6.

Once they had developed a PURE diet score, they expanded their data by including five additional large independent studies that included people from 70 countries. The combined data from all six studies amounted to 245,597 people from 80 countries. Of the people included in the data analysis:

  • 21% came from high income countries.
  • 60% came from middle income countries.
  • 19% came from low-income countries.

This is very similar to the global population distribution. This is a strength of this study because it allowed them to ask whether the PURE diet score worked as well in low-income countries as in high-income countries.

Finally, they correlated the PURE diet score with outcomes like all-cause mortality, heart attack, and stroke.

Is Whole Fat Dairy Healthy?

QuestionsThe authors of this study divided the participants of all 6 studies into quintiles based on their PURE diet score and compared those in the highest quintile (PURE score of ≥ 5) with those in the lowest quintile (PURE score of ≤ 1).

The people in the highest quintile were eating on average 5 servings/day of fruits and vegetables, 0.5 servings/day of legumes, 1.2 servings/day of nuts, 0.3 servings/day of fish, 2 servings/day of dairy (of which 1.4 servings/day was whole fat dairy), 0.5 servings/day of unprocessed red meat, and 0.3 servings/day of poultry.

 

The people in the lowest quintile ate significantly less fruits, vegetables, nuts, fish, and dairy; and slightly less legumes, unprocessed red meat, and poultry than those in the highest quintile.

However, they consumed significantly more refined wheat foods and white rice. This study did not track consumption of highly processed foods, but the high consumption of white flour leads me to suspect they ate a lot more highly processed food.

With that in mind, when the authors compared people with the highest PURE diet scores to those with the lowest PURE diet scores:

  • All-cause mortality was reduced by 30%.
  • Cardiovascular disease was reduced by 18%.
  • Heart attacks were reduced by 14%.
  • Strokes were reduced by 19%.
  • The PURE healthy eating score was slightly better at predicting health outcomes than the Mediterranean, DASH, and HEI (Healthy Eating Index) scores. But the differences were small. So, I still recommend choosing the healthy diet that best fits your preferred foods and your lifestyle.
  • The PURE healthy eating score was significantly better at predicting health outcomes than the Planetary diet score. I will discuss the nutritional inadequacy of “sustainable diets” like the Planetary diet in next week’s “Health Tips From the Professor” article.

Because of the size and design of this study, they were able to make three interesting observations.

  1. The PURE, Mediterranean, DASH, and HEI diet scores were predictive of health outcomes in every country across the globe. You no longer have to wonder if what works in the United States will work in low-income countries and in countries with very different food preferences. Previous studies have not been able to make that claim.

2) You don’t have to be perfect.

    • A 20% increase (one quintile) in PURE score was associated with a 6% lower risk of major cardiovascular events and an 8% lower risk of mortality. In other words, even small improvements in your diet may improve your health outcomes.
    • The health benefits of the PURE diet started to plateau at a score of 3 (with 6 being the highest score). The authors concluded that most of the health benefits were associated with a modestly higher consumption of healthy foods compared to little or no consumption of healthy foods.

Simply put, that means the health benefits gained by going from a moderately healthy diet to a very healthy diet are not as great as the health benefits gained by going from a poor diet to a moderately healthy diet.

[Note: There are still improvements in health outcomes when you go from a moderately healthy diet to a very healthy diet.  My recommendation: “You don’t need to achieve perfection, but you shouldn’t accept mediocrity”.]

3) The PURE diet score was more predictive of health outcomes in some countries than in others.

    • The PURE diet score was more predictive of health outcomes in low-income countries. The authors felt that was because low-income countries started with average PURE scores of 2.1, whereas higher-income countries started with average PURE scores of 3.5.

The authors felt this was another example getting more “bang for the buck” by going from a poor diet to a moderately healthy diet than from a moderately healthy diet to a very healthy diet. (Remember, the health benefits associated with improving PURE diet scores start to plateau at a PURE score of 3.

    • The difference in benefits for low-income countries compared to high-income countries was observed for the Mediterranean, DASH, and HEI diet scores. So, it is probably safe to say for any healthy diet you don’t need to be perfect. You just need to be better.

The authors concluded, “A diet composed of higher amounts of fruit, vegetables, nuts, legumes, fish, and whole fat dairy is associated with a lower risk of cardiovascular disease and mortality in all world regions, especially in countries with lower income where consumption of these foods is low.”

Is It Dairy Or Diet?

CheesesThe headlines are telling us that recommendations to choose low-fat dairy products are out of date. They say there is no reason to fear whole fat dairy foods. They are good for you. Bring on the ice cream, sour cream, cream cheese, and high fat hard cheeses!

As usual, there is a kernel of truth in the headlines, but headlines have to be simple. And the latest headlines are an oversimplification of what the studies actually show. Let me provide perspective to the headlines by asking two questions.

#1: Is it dairy or diet? A major weakness of this and similar studies is that they fail to consider diet context. What do I mean by that? Let’s dig a little deeper into this study.

  • Let’s start with a description of the PURE diet. It is a diet that emphasizes fruits, vegetables, legumes, nuts, and fish. In other words, it is a primarily plant-based diet.
  • Although the authors keep referring to the diet as one that includes whole fat dairy. It would be more accurate to say that it includes dairy, which was 30% low-fat and 70% whole fat.
  • The authors said that removal of any one food group from this combination reduced the predictive power of the PURE diet. In other words, the beneficial effect of 70% whole fat dairy is best seen in the context of a primarily plant-based diet.
  • The PURE diet was most effective at predicting health outcomes in low-income countries where a significant percent of the population consumes a primarily plant-based diet because meats are expensive.

So, a more accurate description of this study would be it shows that a mixture of low-fat and whole-fat dairy foods are a healthy addition to a primarily plant-based diet. But that is too complicated for a headline.

#2: If whole fat dairy can be part of a healthy diet, can it also be part of an unhealthy diet?

To answer that question let’s compare the potential effects of whole fat dairy on a primarily plant-based diet compared to the typical American or European diet.

  • Milk and other dairy foods are excellent sources of calcium, vitamin B12, and iodine and good sources of protein, vitamin D, choline, zinc, and selenium – nutrients that are often low or missing in plant-based diet. And this is true whether the dairy foods are low-fat or whole fat.
  • Primarily plant-based diets tend to be low in saturated fat, so the potential negative effects of adding a small amount of saturated fat to the diet may be outweighed by the beneficial effects of the nutrients dairy foods provide.

On the other hand,

  • The typical American or European diet provides plenty of protein and vitamin B12 and significantly more choline, vitamin D, iodine, and zinc than a plant-based diet. The added nutrients from adding dairy foods to this kind of diet is still beneficial, but the benefits are not as great as adding dairy foods to a primarily plant-based diet.
  • If you read the American Heart Association statement on saturated fats, it does not say that any amount of saturated fat is bad for you. In fact, small amounts of saturated fats play some beneficial roles in our bodies. The American Heart Association says, “Eating too much saturated fat can raise the level of LDL cholesterol in your blood…[which] increases your risk of heart disease and stroke.”
  • Here is where the problem lies. The typical American or European diet already contains too much saturated fat. Whole fat dairy just adds to that excess.

So, the most accurate description of this study would be it shows that a mixture of low-fat and whole-fat dairy foods are a healthy addition to a primarily plant-based diet but may not be a healthy addition to the typical American diet. But that is way too complicated for a headline.

You are probably wondering what this means for you. Here are my recommendations.

If you eat like most Americans, you should continue to follow the current health guidelines to choose low-fat dairy foods.

If you happen to be among the few Americans who eat a primarily plant-based diet, you will probably benefit by adding a mixture of low-fat and whole fat dairy foods to your diet.

The Bottom Line 

Once again, the headlines are telling us that recommendations to choose low-fat dairy products are out of date. The articles say there is no reason to fear whole fat dairy foods. They are good for you. Bring on the ice cream, sour cream, cream cheese, and high fat hard cheeses!

As usual, there is a kernel of truth in the headlines, but headlines have to be simple. And the latest headlines are an oversimplification of what the studies actually show. In this post I looked at the study behind the most recent headlines and provided perspective to the headlines by asking two questions.

#1: Is it dairy or diet? A major weakness of this and similar studies is that they fail to consider diet context.

When you consider diet context a more accurate description of this study would be it shows that a mixture of low-fat and whole-fat dairy foods are a healthy addition to a primarily plant-based diet. But that is too complicated for a headline.

#2: If whole fat dairy can be part of a healthy diet, can it also be part of an unhealthy diet?

When you consider that question the most accurate description of this study would be it shows that a mixture of low-fat and whole-fat dairy foods are a healthy addition to a primarily plant-based diet but may not be a healthy addition to the typical American diet. But that is way too complicated for a headline.

You are probably wondering what this means for you. Here are my recommendations.

If you eat like most Americans, you should continue to follow the current health guidelines to choose low-fat dairy foods.

If you happen to be among the few Americans who eat a primarily plant-based diet, you will probably benefit by adding a mixture of low-fat and whole fat dairy foods to your diet.

For more information on this study, and the science behind my summary of the 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

Are All Carbs Bad?

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Are Low Carb Enthusiasts Right About The Dangers Of Carbohydrates?

Author: Dr. Stephen Chaney 

Low carb enthusiasts have been on the warpath against carbohydrates for years.

Almost everyone agrees that sugar-sweetened sodas and highly processed, refined foods with added sugar are bad for us. But low carb enthusiasts claim that we should also avoid fruits, grains, and starchy vegetables. Have they gone too far?

Several recent studies suggest they have. For example, both association studies and randomized controlled studies suggest that total carbohydrate intake is neither harmful nor beneficial for heart health.

In addition, recent studies suggest that free sugar intake is associated with both elevated triglyceride levels and an increase in heart disease risk.

But those studies have mostly looked at free sugar intake from sugar-sweetened sodas. The authors of this study (RK Kelley et al, BMC Medicine, 21:34, 2023) decided to look more carefully at the effect of all free sugars and other types of carbohydrates on triglyceride levels and heart disease risk.

How Was This Study Done?

clinical studyThe 110,497 people chosen for this study were a subgroup of participants in the UK Biobank Study, a large, long-term study looking at the contributions of genetic predisposition and environmental exposure (including diet) to the development of disease in England, Scotland, and Wales.

The participants in this study were aged between 37 and 73 (average age = 56) on enrollment and were followed for an average of 9.4 years. None of them had a history of heart disease or diabetes or were taking diabetic medications at the time of enrollment.

During the 9.4-year follow-up, five 24-hour dietary recalls were performed, so that usual dietary intake could be measured rather than dietary intake at a single time point. The people in this study participated in an average of 2.9 diet surveys, and none of them had less than two diet surveys.

The averaged data from the dietary recalls were analyzed for the amount and kinds of carbohydrate in the diet. With respect to the types of carbohydrate, the following definitions would be useful.

  • The term free sugars includes all monosaccharides and disaccharides added to foods by the manufacturer, cook, or consumer, plus sugars naturally present in honey, syrups, and unsweetened fruit juices.
  • The term non-free sugars includes all sugars not in the free sugar category, mostly sugars naturally occurring in fruits, vegetables, and dairy products.
  • The term refined grains includes white bread, white pasta, white rice, most crackers and cereals, pizza, and grain dishes with added fat.
  • The term whole grains includes wholegrain bread, wholegrain pasta, brown rice, bran cereal, wholegrain cereals, oat cereal, and muesli.

Finally, the study looked at the association of total carbohydrate and each class of carbohydrate defined above with all heart disease, heart attacks, stroke, and triglyceride levels.

Are All Carbs Bad?

Question MarkThe study looked at total carbohydrate intake, free sugar intake, and fiber intake. In each case, the study divided the participants into quartiles and compared those in the highest quartile with those in the lowest quartile.

Using this criterion:

  • Total carbohydrate intake was not associated with any cardiovascular outcome measured (total heart disease risk, heart attack risk, and stroke risk).
  • Free sugar intake was positively associated with all cardiovascular outcomes measured. Each 5% increase in caloric intake from free sugars was associated with a:
    • 7% increase in total heart disease risk.
    • 6% increase in heart attack risk.
    • 10% increase in stroke risk.
    • 3% increase in triglyceride levels.
  • Fiber intake was inversely associated with total heart disease risk. Specifically, each 5 gram/day increase in fiber was associated with a:
    • 4% decrease in total heart disease risk.

The investigators also looked at the effect of replacing less healthy carbohydrates with healthier carbohydrates. They found that:

  • Replacing 5% of caloric intake from refined grains with whole grains reduced both total heart disease risk and stroke risk by 6%.
  • Replacing 5% of caloric intake from free sugars (mostly sugar-sweetened beverages, fruit juices, and processed foods with added sugar) with non-free sugars (mostly fruits, vegetables, and dairy products) reduced total heart disease risk by 5% and stroke risk by 9%.

Are Low Carb Enthusiasts Right About The Dangers Of Carbohydrates?

With these data in mind let’s look at the claims of the low-carb enthusiasts.

Claim #1: Carbohydrates raise triglyceride levels. This study shows:

  • This claim is false with respect to total carbohydrate intake and high fiber carbohydrate intake (fruits, vegetables, and whole grains. This study did not measure intake of beans, nuts, and seeds, but they would likely be in the same category).
  • However, this claim is true with respect to foods high in free sugars (sugar-sweetened beverages, fruit juices, and processed foods with added sugar).

Claim #2: Carbohydrates increase heart disease risk. This study shows:

  • That claim is false with respect to total carbohydrate intake and high fiber carbohydrate intake.
  • However, this claim is true with respect to foods high in free sugars.

Claim #3: Carbohydrates cause weight gain [Note: Low carb enthusiasts usually word it differently. Their claim is that eliminating carbohydrates will help you lose weight. But that claim doesn’t make sense unless you believed eating carbohydrates caused you to gain weight.] This study shows:

  • This claim is false with respect to total carbohydrate intake and high fiber carbohydrate intake.
  • Once again, this claim is true with respect to foods high in free sugars.

The data with high fiber carbohydrates was particularly interesting. When the authors compared the group with the highest fiber intake to the group with the lowest fiber intake, the high-fiber group:

  • Consumed 33% more calories per day.
  • But had lower BMI and waste circumference (measures of obesity) than the low-carbohydrate group.

This suggests that you don’t need to starve yourself to lose weight. You just need to eat healthier foods.

And, in case you were wondering, the high fiber group ate:

  • 5 more servings of fruits and vegetables and…
  • 2 more servings of whole grain foods than the low fiber group.

This is consistent with several previous studies showing that diets containing a lot of fruits, vegetables, and whole grains are associated with a healthier weight.

The authors concluded, “Higher free sugar intake was associated with higher cardiovascular disease incidence and higher triglyceride concentrations…Higher fiber intake and replacement of refined grain starch and free sugars with wholegrain starch and non-free sugars, respectively, may be protective for incident heart disease.”

In short, with respect to heart disease, the type, not the amount of dietary carbohydrate is the important risk factor.

What Does This Mean For You?

Questioning WomanForget the low carb “mumbo jumbo”.

  • Carbohydrates aren’t the problem. The wrong kind of carbohydrates are the problem. Fruit juice, sugar-sweetened sodas, and processed foods with added sugar:
    • Increase triglyceride levels.
    • Are associated with weight gain.
    • Increase the risk for heart disease.
  • In other words, they are the villains. They are responsible for the bad effects that low carb enthusiasts ascribe to all carbohydrates.
  • Don’t fear whole fruits, vegetables, dairy, and whole grain foods. They are the good guys.
    • They have minimal effect on triglyceride levels.
    • They are associated with healthier weight.
    • They are associated with a lower risk of heart disease and diabetes.

So, the bottom line for you is simple. Not all carbs are created equal.

  • Your mother was right. Eat your fruits, vegetables, and whole grains.
  • Avoid fruit juice, sodas and other sugar-sweetened beverages, and processed foods with added sugar. [Note: Artificially sweetened beverages are no better than sugar-sweetened beverages, but that’s another story for another day.]

And, if you were wondering why low carb diets appear to work for weight loss, it’s because any restrictive diet works short term. As I have noted previously, keto and vegan diets work equally well for short-term weight loss.

The Bottom Line 

Low carb enthusiasts have been telling us for years to avoid all carbohydrates (including fruits, starchy vegetables, and whole grains) because carbohydrates:

  • Increase triglyceride levels.
  • Cause weight gain.
  • Increase our risk for heart disease.

A recent study has shown that these claims are only true for some carbohydrates, namely fruit juices, sodas and other sugar-sweetened beverages, and processed foods with added sugar.

Whole fruits, vegetables, and whole grain foods have the opposite effect. They:

  • Have a minimal effect on triglyceride levels.
  • Are associated with a healthier weight.
  • Are associated with a lower risk of heart disease and diabetes.

So, forget the low carb “mumbo jumbo” and be sure to eat your fruits, vegetables, and whole grains.

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

Is HDL Good For Your Heart?

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Is Everything You Knew About HDL Wrong?

Author: Dr. Stephen Chaney 

HDL CHolesterolIn last week’s “Health Tips From the Professor” I 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.

Last week I shared a study that disproved the paradigm that low to moderate alcohol consumption is healthier than total abstinence. This week I 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 underlying HDL/heart health paradigm weren’t true? These hypotheses would be like the parable of a house built on a foundation of sand. The paradigm will be washed away as soon as it is critically tested.

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

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.

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 16 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.

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 likely 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”. I described the term and how it affects clinical studies in last week’s article. 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 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.Heart Disease Study

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:

  • 7.1% reduction in heart disease events (both heart disease deaths and non-fatal heart attacks).
  • 7.2% reduction in heart disease deaths.
  • 4.4% 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.

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 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 HDL/heart health paradigm – 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

Is Erythritol Bad For Your Heart?

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Who Should Be Concerned About Erythritol Intake?

Author: Dr. Stephen Chaney 

Everyone is searching for the perfect sweetener. And if you were in the marketing department of Big Food Inc, the perfect sweetener would be defined as:

  • Natural, meaning that it is found in fruits, vegetables, or other plant foods.
  • Low in calories. Of course, a perfect sweetener would have zero calories because it is not metabolized in our bodies.
  • Low glycemic, meaning that it would have a minimal effect on blood sugar levels. Once again, a perfect sweetener would have zero effect on blood sugar levels.
  • Safe, meaning that it has no adverse effects on our health.

Sugar alcohols appear to meet all these criteria, so they have become the sweetener of choice for lots of highly processed foods. This is especially true for the sugar alcohol, erythritol, since it is currently the least expensive of the sugar alcohols.

So, a recent study (M Witowski et al, Nature Medicine, 2023) suggesting that erythritol might increase the risk of heart disease was quite surprising.

This is the first study to suggest a link between erythritol and heart disease, and it was a flawed study (I will discuss the flaws below).

Reputable scientists don’t put much credence in a weak first study like this one. We generally consider the conclusions of a first study like this one to be an unproven hypothesis at this point.

But we are cautious. There will be many follow-up, better designed studies, to test this hypothesis. Once these studies have been published, the scientific community will look at all the evidence and either issue a warning or conclude that there is no reason for concern.

But that doesn’t stop the Dr. Strangeloves of the world from warning you of the “dangers” of erythritol and telling you to avoid it at all costs.

For that reason, I felt it was appropriate to address this issue. I will:

  • Describe the study and its flaws.
  • Put the study into the broader perspective of what we know about sweeteners.
  • Identify the two population groups who should be most concerned about erythritol.

How Was The Study Done And What Did It Show?

This study can be divided into three parts.

heart disease#1: An Association Between Erythritol Blood Levels And Heart Disease.

There were three separate experiments included in this section of the study. In each experiment patients were recruited after visiting cardiac clinics for diagnostic procedures. The average age of these patients was 67 and 45% of them already had experienced a non-fatal heart attack prior to the study. In other words, these were all older patients with pre-existing heart disease who were at high risk of heart attack or stroke in the near future.

The first study was a metabolomic study. In simple terms this means that high-tech equipment and computing were used to measure hundreds of metabolites in the blood of the patients and, in this case, correlate each of them with the occurrence of heart attacks and strokes over the next three years.

  • This study identified 16 sugar alcohols and related metabolites in the blood of these patients that were associated with an increased risk of heart attack and stroke. (I will discuss the significance of this observation in more detail later.)

Because erythritol was among the top 6 compounds in terms of association with increased heart attack and stroke risk, and erythritol is the most commonly used sugar alcohol in processed foods, the next two studies focused on the association between blood levels of erythritol and heart attack/stroke risk. Their results were predictable.

  • High blood levels of erythritol were associated with an increased risk of heart attack and stroke over the next three years.

Flaws In This Portion Of The Study:thumbs down symbol

  • As the authors of the study pointed out, these studies were done with older patients with pre-existing heart disease who were at high risk of heart attack or stroke. They acknowledged that it is not known whether these associations exist with younger, healthier patients.
  • As the authors also pointed out, these are associations. They do not prove cause and effect. In particular, the studies did not measure the diet, exercise habits, and other lifestyle factors of these patients that may have contributed to their increased risk of heart attack and stroke.
  • When you look closely at the data, it is clear that the association is only seen at the highest blood levels of erythritol. Specifically, the blood levels of erythritol in these patients were divided into quartiles. The risk of heart attack and stroke in the first three quartiles (low to moderate blood levels of erythritol) were identical to the control. However, the fourth quartile (highest blood levels of erythritol) was associated with a dramatically increased risk of heart attack and stroke. That raises three important questions:
    • “How much erythritol were patients in the fourth quartile consuming?”
      • The authors did not look at dietary intake of erythritol but did note a previous study estimated that Americans consume up to 30 grams of erythritol a day.
    • 30 grams of erythritol a day is a huge amount of erythritol. Where does that erythritol come from?
      • Much of it comes from erythritol-containing highly processed foods like zero calorie sugar substitutes (either erythritol alone or erythritol mixed with artificial sweeteners to improve the taste); reduced- and low calorie carbonated and non-carbonated beverages; hard candy and cough drops, cookies, cakes, pastries, and bars; puddings and pie fillings; soft candies; syrups and toppings; ready to eat cereals; fruit novelty snacks; and frozen desserts.
      • But it is also found in foods you might not suspect, such as plant-based “milk” substitutes; chocolate and flavored milks; barbecue and tomato sauce, fruit-based smoothies, the syrup used in canned fruits, yoghurt; low calorie salad dressings; and salty snacks.
      • In other words, the only way anyone can consume 30 grams of erythritol in a day is to consume large quantities of erythritol-containing highly processed foods (I will discuss the significance of this observation later).
    • “What else was different about patients in the fourth quartile?”
      • When you look carefully at the data, the patients in the fourth quartile were significantly older, with a higher incidence of diabetes, pre-existing coronary artery disease, previous non-fatal heart attacks, congestive heart failure, and greater triglycerides – all of which significantly increase their risk of heart attack and stroke.

#2: Mechanistic Studies:

Next the authors did in vitro and animal studies looking at the effect of high levels of erythritol on blood clotting.

  • These studies showed that high levels of erythritol promoted blood clotting both in vitro and in mice. The authors concluded that these studies provided a plausible mechanism for a link between high erythritol blood levels and increased risk of heart attack and stroke.

Flaws In This Portion Of The Study:thumbs down symbol

  • Other critics have pointed out that the assays used were not accurate models of blood clotting in humans. This particular critique is beyond my expertise, so I won’t comment further. However:
    • As someone who was involved in cancer drug development for over 30 years, I know that in vitro and animal models are poor indicators of how things work in humans.
    • And as a biochemist, I have two concerns:
      • The authors provided no mechanistic rationale for why erythritol would enhance blood clotting.
      • The authors made no effort to show that the effect of erythritol was unique. Would high levels of other sugar alcohols or other naturally occurring sugars have the same effect on blood clotting in their assays? We don’t know.

#3: Blood Levels Of Erythritol After Oral Intake.

Finally, the authors gave subjects 30 grams of erythritol and measured blood levels over the next several days.

  • This experiment showed that very high blood levels of erythritol were attained and maintained for at least two days before gradually decreasing to baseline. The authors concluded this experiment showed that it was feasible to attain and maintain high blood levels of erythritol for several days following a single ingestion of 30 grams of erythritol.

Flaws In This Portion Of The Study:thumbs down symbol

  • I have already pointed out that 30 grams per day is a huge amount of erythritol. However, erythritol in the diet will come from a variety of foods, some of which will contain components (fiber etc.) that slow the absorption of erythritol.
  • In contrast, the subjects in this experiment were given 300 ml of liquid containing 30 grams of erythritol and told to drink it in two minutes!
  • In other words, these subjects were consuming 30 grams of erythritol in 2 minutes rather than 24 hours, and they were consuming it in the most easily absorbable form. For a study like this, that makes the effective dose orders of magnitude greater than the amount of erythritol that anyone consumes from their diet over a 24-hour period. The study design was completely unrealistic.

Is Erythritol Bad For Your Heart?

Question MarkAs described above, this is the first study to suggest an association between erythritol and heart disease, and it was a highly flawed study.

It is also important to know that erythritol is not an artificial sweetener. It is found naturally in foods like grapes, peaches, pears, watermelons, and mushrooms. It is also found in some fermented foods like cheese, soy sauce, beer, sake, and wine.

It is also a byproduct of normal human metabolism, so we always have some of it circulating in our bloodstream. Our body knows how to handle low to moderate intakes of erythritol.

However, to help you really understand what this study means, I need to put it into the context of other studies. I will do this in story form (You will find more details about these studies in my book “Slaying The Food Myths”).

First, let’s look at highly processed food consumption:

  • Multiple recent studies have shown that high consumption of highly processed food is associated with increased risk of obesity, diabetes, heart disease, and premature death. We don’t know what it is about highly processed food consumption that is responsible for the increased risk, but it is unlikely to be just one thing.
  • As I pointed out above, the only way to achieve the high blood levels of erythritol associated with increased heart disease risk is to consume large quantities of erythritol-containing highly processed foods.

Next, let’s follow the history of sweeteners in highly processed foods.

  • When I was a young man, sucrose (table sugar) was added to most highly processed foods. Sucrose is foundsugar cubes naturally in many fruits and vegetables. Small to moderate intake of sucrose in unprocessed and minimally processed foods posed no problem. However, large intakes of sugar in highly processed foods were found to increase the risk of obesity, diabetes, heart disease, and premature death.
  • At that point, sucrose became a “sugar villain”, and Big Food, Inc substituted fructose and high fructose corn syrup (a mixture of fructose and glucose) for sugar in their highly processed foods. As with sucrose, fructose is found naturally in many foods, and small to moderate intakes of fructose and high fructose corn syrup posed no health risks. However, large intakes of fructose and high fructose corn syrup in highly processed foods were found to increase the risk of obesity, diabetes, heart disease, and premature death.
  • Fructose and high fructose corn syrup then became the sugar villains. And because high fructose corn syrup is chemically and biologically indistinguishable from natural sugars like honey, date sugar, coconut sugar, it is likely that high intakes of these sugars in highly processed foods would cause the same problem.
  • So Big Food, Inc started relying on artificial sweeteners in their highly processed foods. But guess what? Artificial SweetenersRecent studies have suggested that artificial sweeteners in highly processed foods are associated with obesity, diabetes, and heart disease.
  • That has caused Big Food, Inc to rely more on sugar alcohols in their highly processed foods, particularly erythritol because it is the least expensive of the sugar alcohols. Now the current study comes along and suggests that high intake of erythritol in highly processed foods may increase the risk of heart disease.
  • If this hypothesis is confirmed by better designed studies, it is not clear what Big Food, Inc will do next. The metabolomic study described above showed that high blood levels of several other sugar alcohols are associated with an increased risk of heart disease.

Hopefully, you are starting to see a pattern here. It’s time to ask the question, “Is it the sweetener, or is it the food?”

Clearly, it doesn’t matter what sweetener we are talking about. Large intake of any natural sweetener in the context of a diet rich in highly processed foods appears to have an adverse effect on our health. And we don’t know whether these adverse health effects are caused by the sweetener or some other component of the highly processed foods.

If you want to improve your health, the best solution is to decrease your intake of highly processed foods. That will automatically reduce your intake of sweeteners and other unhealthy components of highly processed foods and increase your intake of healthy components from the whole foods you will be eating instead.

Who Should Be Concerned About Erythritol Intake?

The authors of this study identified two groups who should be most concerned about erythritol consumption – diabetics and adherents of the keto diet.

  • Diabetics are at high risk because they are told to consume non-caloric sweeteners instead of sugars, and they are not told to avoid highly processed foods. Consequently, they consume much higher amounts of non-caloric sweeteners than the average American.
  • I must admit that I didn’t foresee keto adherents as a high-risk group. However, it appears that keto enthusiasts love their sweets as much as the rest of us, and the sweetener of choice for keto-friendly sweets is erythritol. The authors said that a single serving of keto ice cream contains 30 grams of erythritol. I can hardly imagine how much erythritol they must be getting in their diet.

And, once again, the best advice for both groups is to simply decrease the amount of highly processed food in their diet.

The Bottom Line 

Erythritol is not an artificial sweetener. It is found naturally in foods like grapes, peaches, pears, watermelons, and mushrooms. It is also found in some fermented foods like cheese, soy sauce, beer, sake, and wine.

It is also a byproduct of normal human metabolism, so we always have some of it circulating in our bloodstream. Our body knows how to handle erythritol.

That is why it was a surprise when a recent study claimed that high intake of erythritol is associated with an increased risk of heart attack and stroke. The Dr. Strangeloves of the world are already starting to tell you that erythritol is deadly and you should avoid it at all costs. But reputable scientists are saying, “Not so fast”.

This is the first study to suggest an association between erythritol and heart disease, and it was a highly flawed study.

In fact, the study showed that low to moderate intakes of erythritol had no effect on heart disease risk. It was only the highest intake of erythritol that was associated with increased risk of heart disease. And given the distribution of erythritol in the American diet, the only way someone could take in that much erythritol is to consume large amounts of erythritol-sweetened highly processed foods.

A brief review of the literature on sweeteners reveals that this is a common pattern for every natural sweetener tested. Low to moderate intake of these sweeteners has no adverse health effects. However, high intake of every sweetener tested in the context of a highly processed food diet is associated with an increased risk of obesity, diabetes, heart disease, and premature death.

That raises the question, “Is it the sweetener, or is it the food?”

Clearly, it doesn’t matter what sweetener we are talking about. Large intake of any natural sweetener in the context of a diet rich in highly processed foods is likely to have an adverse effect on our health. And we don’t know whether these adverse health effects are caused by the sweetener or some other component of a highly processed food diet.

If you want to improve your health, the best solution is to decrease your intake of highly processed foods. That will automatically reduce your intake of sweeteners and other unhealthy components of highly processed foods and increase your intake of healthy components from the whole foods you will be eating instead.

For more details on the study and information about which foods are likely to contain erythritol and the population groups who should be most concerned about erythritol consumption, 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

Does Magnesium Protect Your Heart?

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Do You Need A Magnesium Supplement?

Author: Dr. Stephen Chaney 

Getting an adequate amount magnesium from our diet should not be a problem. Magnesium is found in a wide variety of foods with the best sources being legumes (beans), nuts, seeds, whole grains, green leafy vegetables, and dairy foods.

The problem is:

  • None of these foods contain enough magnesium by themselves to provide the RDA (420 mg/day for men and 320 mg/day for women) for magnesium. We need to consume a variety of these foods every day – something most Americans aren’t doing.
  • These foods are decent sources of magnesium only in their unprocessed form. And most Americans consume more highly processed foods than whole, unprocessed foods.
  • Two to three servings of dairy provide a decent amount of magnesium, but many Americans are cutting back on dairy. And plant-based dairy substitutes often provide much less magnesium than the dairy food they replace.
  • Finally, green leafy vegetables (iceberg lettuce doesn’t count) don’t make it into the American menu as often as they should.

As a result, recent studies find that at least 50% of Americans are not getting enough magnesium in their diet. In fact, the average magnesium intake in this country is 268 mg/day for men and 234 mg/day for women. And the figures are not very different in other developed countries.

Does it matter? Recent studies have shown that an adequate intake of dietary magnesium is associated with lower risks of cardiovascular diseases (CVD) and all-cause mortality. This may be because of the of role of magnesium in supporting heart muscle contraction, normal heart rhythm, and blood pressure regulation. Adequate magnesium intake is also associated with lower risk of type 2 diabetes.

But what if you have already had a heart attack? Is it too late for magnesium to make a difference? A recent study (I Evers et al, Frontiers in Cardiovascular Medicine, August 12, 2022) was designed to answer this question.

The authors examined the effect of magnesium intake on cardiovascular disease (CVD) mortality, all-cause mortality, and coronary heart disease (CHD) mortality in patients who had experienced a recent heart attack.

[Note: CHD is defined as heart disease due to clogged coronary arteries, such as a heart attack. CVD includes CHD plus diseases caused by other clogged blood vessels, such as strokes and peripheral artery disease].

How Was The Study Done?

clinical studyThe authors used data from a previous study that had enrolled 4,365 Dutch patients aged 60-80 (average age = 69) who had experienced a heart attack within approximately 4 years prior to enrollment and followed them for an average of 12.4 years. All patients were receiving standard post-heart attack drug therapy.

The characteristics of the patients enrolled in the study were as follows:

  • Male 79%, female 21%
  • Average magnesium intake = 302 mg/day
  • Percent magnesium deficient: 72% of men and 67% of women
  • Percent taking magnesium supplements = 5.4%
  • Percent on drugs to lower blood pressure = 90%
  • Percent on statins = 86%
  • Percent on diuretics = 24%

Upon entry into the study the patients were asked to fill out a 203-item food frequency questionnaire reflecting their dietary intake over the past month. Trained dietitians reviewed the questionnaires and phoned the participants to clarify any unclear or missing items. The questionnaires were linked to the 2006 Dutch Food Composition Database to calculate magnesium intake and other aspects of their diets.

The patients were divided into 3 groups based on their energy adjusted magnesium intakes and those in the highest third (>322 mg/day) were compared to those in the lowest third (<238 mg/day) with respect to cardiovascular disease (CVD), all-cause mortality, and coronary heart disease (CHD) mortality.

The comparisons were statically adjusted for fiber intake (most magnesium-rich foods are also high fiber foods), diuretic use (diuretics reduce magnesium levels in the blood), age, sex, smoking, alcohol use, physical activity, obesity, education level, caloric intake, calcium, vitamin D, sodium from foods, potassium, heme iron, vitamin C, beta-carotenoids, polyunsaturated fatty acids, saturated fatty acids, overall diet quality based on the Dutch Dietary Guidelines, systolic blood pressure, kidney function, and diabetes. In other words, the data were adjusted for every conceivable variable that could have influenced the outcome.

Does Magnesium Protect Your Heart?

When those with the highest magnesium intake (>322 mg/day) were compared to those with the lowest intake (<283 mg/day):

  • Cardiovascular disease (CVD) mortality was reduced by 28%.
  • All-cause mortality was reduced by 22%.
  • Coronary heart disease (CHD) mortality was reduced by 16%, but that reduction was not statistically significant.

They then looked at the effect of some variables that might affect CVD risk on the results.

  • Diabetes, kidney function, iron intake, smoking, alcohol use, blood pressure, most dietary components and overall diet quality had no effect on the results.
  • The results were also not affected when patients using a magnesium supplement were excluded from the analysis. This suggests the effect of magnesium from diet and supplementation is similar.
  • However, diuretic use had a significant effect on the results.
    • For patients using diuretics, high magnesium intake versus low magnesium intake reduced CVD mortality by 45%.

How Much Magnesium Do You Need?

Question MarkYou may have noticed that the difference between the highest magnesium intake group and the lowest intake group was, on average, only 39 mg/day. So, the authors also used a statistical approach that utilized data from each individual patient to produce a graph of magnesium intake versus risk of CVD, total, and CHD mortality. For all 3 end points the graphs showed an inverse, linear relationship between magnesium and mortality.

From this, the authors were able to calculate the effect of each 100mg/day increase in magnesium intake on mortality risk. Each 100mg/day of added magnesium reduced the risk of:

  • CVD mortality by 38%.
  • All-cause mortality by 30%.
  • CHD mortality by 33%, and these results were borderline significant.

The inverse relationship between magnesium intake was observed at intakes ranging from around 200 mg/day to around 450 mg/day, which represented the range of dietary magnesium intake in this Dutch population group.

This study did not define an upper limit to the beneficial effect of magnesium intake because the graphs had not plateaued at 450 mg/day, suggesting that higher magnesium intakes might give even better results.

The authors concluded, “We observed a strong, linear inverse association of dietary magnesium with CVD and all-cause mortality after a heart attack, which was most pronounced in patients who used diuretics. Our findings emphasize the importance of an adequate magnesium intake in CVD patients, on top of cardiovascular drug treatment.”

I might add that this is the first study to look at the effect of magnesium on long-term survival after a heart attack.

Do You Need A Magnesium Supplement? 

magnesium supplements benefitsAs I said earlier, the best dietary sources of magnesium are beans, nuts, seeds, whole grains, green leafy vegetables, and dairy foods. And:

  • None of these foods contain enough magnesium by themselves to provide the RDA (420 mg/day for men and 320 mg/day for women) for magnesium.
  • These foods are decent sources of magnesium only in their unprocessed form.

When unprocessed, each of these foods provides 20 to 60 mg of magnesium per serving. If we use an average value of 40 mg/serving, you would need in the range of 8-10 servings/day of these foods in their unprocessed form to meet the RDA for magnesium.

You could get a more accurate estimate of the magnesium content of your diet using the “Magnesium Content of Selected Foods” table from the NIH Factsheet on Magnesium.

Now you are ready to ask yourself two questions:

  1. Does my current diet provide the RDA for magnesium?

2. If not, am I willing to make the dietary changes needed to increase my magnesium levels to RDA levels?

If your answer to both questions is no, you should probably consider a magnesium supplement. A supplement providing around 200 mg of magnesium should bring all but the worst diets up to the recommended magnesium intake.

The current study did not define an upper limit for the beneficial effect of magnesium on survival after a heart attack but suggested that intakes above 450 mg/day might be optimal.

I do not recommend megadoses of magnesium, but intakes from diet and supplementation that slightly exceed the RDA appear to be safe. In their Magnesium Factsheet, the NIH states, “Too much magnesium…does not pose a health risk in healthy individuals because the kidneys eliminate excess amounts in the urine.”

The only concern is that magnesium from supplements is absorbed much more rapidly than magnesium from foods, and this can cause gas, bloating, and diarrhea in some individuals. For this reason, I recommend a sustained release magnesium supplement, so the magnesium is absorbed more slowly.

Finally, we should not consider magnesium as a magic bullet. The current study statistically eliminated every known variable that might affect survival after a heart attack, so it could estimate the beneficial effects of magnesium alone.

However, survival after a heart attack will likely be much greater if diet, exercise, and body mass are also optimized.

The Bottom Line 

Recent studies have shown that an adequate intake of dietary magnesium is associated with lower risks of cardiovascular diseases (CVD) and all-cause mortality.

But what if you have already had a heart attack? Is it too late for magnesium to make a difference? A recent study of heart attack patients in Holland was designed to answer this question.

The authors examined the effect of magnesium intake on cardiovascular disease (CVD) mortality, all-cause mortality, and coronary heart disease (CHD) mortality in patients who had experienced a recent heart attack.

When heart attack patients with the highest magnesium intake (>322 mg/day) were compared to those with the lowest intake (<283 mg/day):

  • Cardiovascular disease (CVD) mortality was reduced by 28%.
  • All-cause mortality was reduced by 22%.
  • Coronary heart disease (CHD) mortality was reduced by 16%, but that reduction was not statistically significant.

The authors went on to look at the inverse linear relationship between magnesium intake and mortality risk. They found that each 100mg/day of added magnesium reduced the risk of:

  • CVD mortality by 38%.
  • All-cause mortality by 30%.
  • CHD mortality by 33%, and these results were borderline significant.

The authors concluded, “We observed a strong, linear inverse association of dietary magnesium with CVD and all-cause mortality after a heart attack…Our findings emphasize the importance of an adequate magnesium intake in CVD patients…”

I might add that this is the first study to look at the effect of magnesium on long-term survival of patients who have suffered a heart attack.

For more details on this study and my discussion of whether you might benefit from a magnesium supplement, 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.

Health Tips From The Professor