Do Processed Foods Increase Your Risk Of Diabetes?

Why Do We Keep Eating Processed Foods?

Fast Food DangersUnless you are Rip Van Winkle and have been asleep for the past 20 years you probably know that the highly processed foods in the typical American diet are bad for your health. But perhaps you didn’t realize just how bad they were.

But first, let’s start with a bit of perspective. Scientists like to be precise. Even healthy foods go through some processing.

  • The oatmeal you ate this morning was either steel-cut or ground. That is processing.
  • The almond butter you put on your whole grain toast this morning was made by roasting and grinding. That is processing.

So, scientists have developed the term “ultra-processed food” to describe the worst of the worse. In short, ultra-processed foods:

  • Usually go through several physical and chemical processes, such as extruding, molding, prefrying, and hydrogenation that can lead to the formation of toxic contaminants. One example you may have heard about recently would be acrylamide in French fries.
  • Typically contain ingredients of no or little nutritive value, such as refined sugar, hydrogenated oils, emulsifiers, artificial sweeteners, thickening agents, and artificial colors. Some of these ingredients have been linked to cancer, heart disease, and premature death.
  • Have long shelf-lives because of added preservatives. This allows migration of chemicals such as bisphenol A from the packaging materials into the food.

Examples of ultra-processed foods include:

  • Sodas
  • Chips
  • Candy and packages of cookies or crackers
  • Most breakfast cereals
  • Boxed cake, cookie, and pancake mix
  • Chicken nuggets and fish sticks
  • Fast food burgers
  • Hot dogs and other processed meats
  • Infant formula
  • Instant noodles
  • Most store-bought ice cream
  • Flavored yogurt

In short, ultra-processed foods include sodas and the junk and convenience foods Americans hold so dear. Even things like infant formula and flavored yogurt make the list.

Evidence of the ill effects of ultra-processed foods on our health is becoming overwhelming. In previous issues of “Health Tips From the Professor” I have shared recent studies that have shown that heavy consumption of ultra-processed foods is linked to increased risk of obesity and cancer. Other studies have linked ultra-processed food consumption with increased risk of depression, heart disease, and premature death.

In this issue of “Health Tips From the Professor” I:

  • Ask the important question, “If we know these foods are so bad for us, why do we still keep eating them?”

How Was The Study Done?

Clinical StudyThe data from this study were taken from an ongoing study in France (the NutriNet-Sante study) looking at associations between nutrition and health. This study began enrolling French adults 18 and older in 2009.

This is a web-based study. Participants are prompted to go to a dedicated website and fill out questionnaires related to things like sex, age, height, weight, smoking status, physical activity, health status, and diet.

With respect to diet, participants filled out a series of 3 nonconsecutive 24-hour dietary records at the time of enrollment and every 6 months. This is a particularly strong feature of this study. Many studies of this type only analyze participant’s diets at the beginning of the study. Those studies have no way of knowing how the participant’s diets may have changed during the study.

Diagnosis of type 2 diabetes for study participants was obtained from the French centralized health records.

The study enrolled 104,708 participants, 20% men and 80% women, and followed them for an average of 6 years. The average age of the participants was 43 years.

Do Processed Foods Increase Your Risk Of Diabetes?

High Blood SugarIn this study the range of ultra-processed foods in the French diet ranged from 7% to 27% (average = 17%). High intake of ultra-processed foods was associated with:

  • Younger participants. Simply put, young people were more likely to drink sodas and eat junk food than older adults.
  • Increased caloric intake. Ultra-processed foods have a higher caloric density than whole, unprocessed foods.
  • No surprise here. Previous studies have shown that ultra-processed food consumption increases the risk of obesity.
  • Poorer diet quality. Again, no surprise. Junk foods tend to crowd healthier foods out of the dirt. Specifically, ultra-processed food consumption was associated with:
    • Higher intake of sugar and salt.
    • Lower intake of fiber.
    • Higher intake of sugary drinks, red and processed meats.
    • Lower intake of whole grains, yogurt, nuts, fruits, and vegetables.

However, even after statistically correcting for all these factors, there was a significant association between ultra-processed food consumption and the onset of type 2 diabetes in the 6-year follow-up period.

  • There was a linear relation between ultra-processed food consumption and the development of type 2 diabetes. Simply put, the more ultra-processed food the participants consumed the more likely they were to be diagnosed with type 2 diabetes.
  • There was a 15% increased risk of developing type 2 diabetes for every 10% increase in ultra-processed food consumption.

The authors concluded:

“In this large observational prospective study, a higher proportion of ultra-processed food in the diet was associated with a higher risk of type 2 diabetes. Even though these results need to be confirmed in other populations and settings, they provide evidence to support efforts by public health authorities to recommend limiting ultra-processed food consumption.”

What Does This Study Mean For You?

Questioning WomanYou might be tempted to say that a 15% increase in the risk of developing diabetes is a small price to pay for continuing to eat the foods you enjoy. However, you should be alarmed by this study. Here is why.

The French diet is much healthier than the American. Remember that ultra-processed foods only comprised 17% of the French Diet. In contrast, a recent survey found that:

  • Ultra-processed foods make up 58% of the average American’s diet.
  • Ultra-processed foods account for 90% of the added sugar in our diet.

It is no wonder that obesity and diabetes are reaching epidemic proportions in our country.

You might also be tempted to think that you can just take some medications and live with type 2 diabetes. However, you should think of type 2 diabetes as a gateway disease. It increases your risk of heart disease, high blood pressure, Alzheimer’s disease, kidney damage, and neuropathy, just to name a few. These are diseases that make your life miserable and ultimately kill you.

More importantly, type 2 diabetes is completely reversible if you catch it early enough. Just lose some weight, exercise more, give up the ultra-processed foods, and eat a healthy diet. I recommend a whole food, primarily plant-based diet.

Why Do We Keep Eating Processed Foods?

Fast FoodsWe all know that ultra-processed foods are bad for us. Study after study show that they make us sick. They kill us prematurely. And, unlike most topics in the field of nutrition, this is not controversial.

For example, there have been lots of bizarre diets that have come and gone over the years. There have been books written on “The Steak Lover’s Diet” and “The Drinking Man’s Diet”. But nobody has written a book on “The Junk Food Lover’s Diet”. It simply would not be believable.

So why do we Americans keep eating such unhealthy foods. Part of the answer is physiological. A preference for sweet, salty, and fatty foods is hardwired into our brain. That’s because they had great survival value in prehistoric times.

If we think back to the time when we were hunters and gatherers:

  • Fruits are healthy foods. They are a great source of antioxidants, phytonutrients, and fiber, but there were no orchards or grocery stores back then. We had to search for fruits in the wild. Our desire for sweet tasting foods provided the motivation to seek them out.
  • Game was seasonal and sometimes scarce. We had to be prepared to go for days or weeks without eating except for the leaves and roots we could gather. Our bodies are designed to store fat as the primary energy source to get us through the lean times. Our preference for fatty foods encouraged us to store as much fat as possible in times of plenty so we would be prepared for times of scarcity.
  • If we fast forward to our early recorded history, salt was scarce. It was worth its weight in gold. Yet some salt is essential for life. Our preference for salty foods encouraged us to search out supplies of salt.

Unfortunately, the food industry has weaponized these food preferences to create the ultra-processed foods we know today. Their ads entice us by associating these foods with youth and good times. And ultra-processed foods have become ubiquitous. There are fast food restaurants on almost every street corner and shopping mall in the country.

Fortunately, we do not have to let the food industry destroy our health. We can retrain our taste buds to appreciate the sweetness of fresh fruits and vegetables. We can substitute healthy fats for the kinds of fat found in most ultra-processed foods. We can also retrain our taste buds to appreciate herbs and spices with just a pinch of salt.

The Bottom Line

Ultra-processed foods, such as sodas, junk foods, and convenience foods have become the biggest food group in the American diet. A recent study found:

  • Ultra-processed foods make up 58% of the average American’s diet.
  • Ultra-processed foods account for 90% of the added sugar in our diet.

That is scary because ultra-processed foods are deadly. Previous studies have shown that consumption of ultra-processed foods is linked to obesity, heart disease, cancer, and Alzheimer’s disease.

The study discussed this week looked at the association between ultra-processed food consumption and type 2 diabetes. It showed:

  • There was a linear relation between ultra-processed food consumption and the development of type 2 diabetes. Simply put, the more ultra-processed food the participants consumed the more likely they were to be diagnosed with type 2 diabetes.
  • There was a 15% increased risk of developing type 2 diabetes for every 10% increase in ultra-processed food consumption.

You might be tempted to think that you can just take some medications and live with type 2 diabetes. However, you should think of type 2 diabetes as a gateway disease. It increases your risk of heart disease, high blood pressure, Alzheimer’s disease, kidney damage, and neuropathy, just to name a few. This are diseases that make your life miserable and ultimately kill you.

More importantly, type 2 diabetes is completely reversible if you catch it early enough. Just lose some weight, exercise more, give up the ultra-processed foods, and eat a healthy diet. I recommend a whole food, primarily plant-based diet.

For more details and a discussion of why Americans continue to eat ultra-processed food even though we know it is bad for us, 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 Eating Plant Protein Help You Live Longer?

Are Whole Grains Heart Healthy?

protein and heart disease nuts and seedsThe diet wars continue. Dr. Strangelove and his colleagues are still trying to convince you that you can eat all the red meat you want. It is those deadly whole grains, beans, and fruits you need to avoid.

However, as the benefits of primarily plant-based diets continue to accumulate, it is becoming harder for them to maintain these preposterous claims.

For example, several recent studies have shown that replacing animal protein with plant protein in your diet results in better health.

  • The Iowa Women’s Health Study found that plant protein substitution for animal protein is associated with reduced risk of dying from heart disease.
  • The Nurse’s Health Study and Health Professionals Follow-up Study found that greater plant protein intake was associated with reduced risk of dying from heart disease and reduced risk of dying from all causes.
  • The Japan Public Health Center-Based Prospective Cohort Study found a reduced risk of dying from heart disease, cancer, and all causes with substitution of plant protein for red meat protein.

These were all very large studies in which populations were followed for long periods of time. You might be thinking that with such overwhelming evidence no further studies are needed.

However, these studies did not examine which plant protein sources were most beneficial and which animal protein sources were most detrimental. The study (J. Huang et al, JAMA Internal Medicine, published online July 13, 2020) I describe in today’s “Health Tips From The Professor” was designed to answer that question.

How Was The Study Done?

Clinical Study416,104 participants from the NIH-AARP Diet and Health Study were enrolled in this study in 1995 and 1996 and were followed for 16 years. At the time of enrollment, the participants filled out a comprehensive Diet History Questionnaire. The participants also completed questionnaires about their health, lifestyle, and socio-economic status.

Deaths were obtained from the Social Security Death Master File. Causes of death were obtained from the National Death Index Plus.

The basic characteristics of the study population were:

  • Gender: 57% men, 43% women.
  • Racial identification: 90% non-Hispanic white.
  • Average age 61 (range 50-71).
  • Average BMI = 27 (in the overweight range).
  • Participants were excluded from the study if they had pre-existing cancer, heart disease, stroke, or end-stage kidney disease.

In terms of protein intake:

  • Average protein intake was 15.3% of calories.
  • Plant protein contributed 40% (range 27% – 57%) to the total protein intake.
  • Animal protein contributed 60% (range = 43% to 63%) of the total protein intake.

The major sources of animal protein in the diet were:

  • Dairy products = 31.6%
  • White meat (poultry, fish, and processed white meat) = 31.3%
  • Red meat (both fresh and processed) = 30.6%
  • Eggs = 4.0%

The major sources of plant protein in the diet were:

  • Grains (bread, cereal, and pasta) = 45.8%
  • Beans and legumes = 8.0%
  • Nuts and seeds = 4.5%
  • Other plant protein (including plant protein from supplements) = 41.7%

All these protein intake figures are normal for the American diet.

I should note that beans, nuts, and seeds are among the best sources of plant protein. However, they are only a minor part of the typical American diet, so they contribute relatively little to our plant protein intake.

Does Eating Plant Protein Help You Live Longer?

In terms of overall protein intake, this study mirrored previous studies.

  • There was an inverse association between plant protein intake and premature death from heart disease, stroke, and all causes. Put another way, the more plant protein people in this study ate, the lower was their risk of premature death.

To quantify the effect, the investigators asked what happened when 3% of calories came from plant protein instead of animal protein. I recognize, however, that 3% of calories is a rather abstract concept, so let me break it down for you so you can apply it to your lives.

  • For participants in this study, protein was 15% of their total calories. That means when the investigators were talking about shifting 3% of total calories from animal protein to plant protein, they were talking about 20% of the protein in the diet coming from plant protein rather animal protein.
  • Based on the average caloric intake of participants in this study, that corresponds to 15 grams of protein for men and 12 grams of protein for women.

With that in mind, let’s look at the results:

  • Changing just 3% of calories from animal protein to plant protein:
  • Lowered the risk of premature death from all causes by 10% for both men and women.
  • Lowered the risk of premature death from cardiovascular disease by 11% for men and 12% for women.
  • Lowered the risk of premature death from stroke by 22% for men and 19% for women.

These findings are consistent with previous studies. By now, it should be apparent that primarily plant-based diets are best for your overall health. Primarily plant-based diets also appear to reduce your risk of dying prematurely from heart disease and from all other diseases combined.

The authors concluded: “This large cohort investigation showed small but significant associations between higher intake of plant protein and lower overall and cardiovascular mortality…Findings from this and previous studies provide evidence that dietary modifications in choice of protein sources may promote health and longevity.”

However, this part of the study merely confirms what other studies have shown. What makes this study unique is that it identifies which animal proteins are worst for us and which plant proteins are best for us.

Which Animal Proteins Are Least Heart Healthy?

Animal Protein FoodsLet’s start with the animal proteins (Note: To simplify a complex set of data, I am going to average the results for men and women).

  • Changing 3% of calories from egg protein to plant protein:
    • Lowered the risk of premature death from all causes by 23%.
    • Lowered the risk of premature death from cardiovascular disease by 27%.
    • To put this into perspective, 3% of calories from egg protein corresponds to around 2.5 eggs/day. So, talking about replacing 3% of calories of egg protein creates a false narrative. The average egg consumption in this study was 0.5 eggs/day and very few participants consumed even 2 eggs every day. If we make a more reasonable comparison, replacing one egg/day with an equivalent amount of plant protein:
      • Lowers the risk of premature death from all causes by 9%.
      • Lowers the risk of premature death from cardiovascular disease by 11%.
  • Changing 3% of calories from red meat protein to plant protein:
    • Lowered the risk of premature death from all causes by 14%.
    • Lowered the risk of premature death from cardiovascular disease by 12%.
    • Lowered the risk of premature death from stroke by 21%.
    • To put this into perspective, 3% of calories from red meat protein corresponds to around 2 ounces/day.
  • Changing 3% of calories from dairy protein to plant protein:
    • Lowered the risk of premature death from all causes by 8%.
    • Lowered the risk of premature death from cardiovascular disease by 11%.
    • Lowered the risk of premature death from stroke by 21%.
    • To put this into perspective, 3% of calories from dairy protein corresponds to around 1.7 8-ounce glasses of milk, 2 ounces of cheese, or 1 cup of yogurt (most yogurt “cups” sold commercially are less than an 8-ounce cup).
  • Changing 3% of calories from white meat protein to plant protein had no effect on premature death from any disease in this study. I will discuss the reasons for that below.

Are Whole Grains Heart Healthy?

Whole GrainsNow, let’s look at the flip side. What happens when you replace 3% of calories from red meat protein with various kinds of plant protein?

  • Changing 3% of calories from red meat protein to plant protein from whole grains:
    • Lowered the risk of premature death from all causes by 28%.
    • Lowered the risk of premature death from cardiovascular disease by 32%.
    • Lowered the risk of premature death from stroke by 32%.
    • To put this into perspective, 3% of calories from whole grain protein corresponds to around 2.5 slices of whole grain bread, 2 cups of oatmeal, or 2.5 cups of brown rice or whole grain pasta – or any combination of them during the day.
  • The results were similar for replacing egg protein with whole grain protein.
  • Changing 3% of calories from red meat protein or egg protein to other types of plant protein had no effect on premature death from any disease. The reasons for that will be discussed below.

The authors concluded “…this investigation showed prominent inverse associations between overall and cardiovascular mortality and the replacement of egg protein and red meat protein with plant protein, particularly for plant protein derived from bread, cereal, and pasta…”

Why Do Animal Proteins Increase Your Risk Of Premature Death?

Let me take a deep dive into the data. If you like, you can skip to “What Does This Study Mean For You?”

To help you gain a better understanding of these results, I will answer two questions for you:

  • Mechanism: What is/are the metabolic explanation(s) for these results?
  • Perspective: How can you apply this information to your own life?

Reminder: This section is for those of you who want the details. I will give the Cliff Notes summary in the section “What Does This Study Mean For You”.

EggsEggs

Mechanism:

  • The bad effect of eggs on cardiovascular mortality and all-cause mortality is thought to be almost exclusively due to their high cholesterol content.
  • On the flip side, eggs are an excellent source of low-fat animal protein and provide nutrients like choline and carotenoids that are often insufficient in the American diet.

Perspective:

  • Our bodies have a beautifully designed system for regulating blood cholesterol levels. This means under ideal conditions dietary cholesterol has very little effect on blood cholesterol levels. However, as I have pointed out in a previous issue of “Health Tips From the Professor”, conditions are often far from ideal.
  • Diet context matters. Obesity, saturated fat, and sugar all interfere with our ability to regulate blood cholesterol levels. People consuming the typical American diet, like the ones in this study, have more difficulty regulating their blood cholesterol levels and are more likely to be adversely affected by dietary cholesterol from eggs and other high-cholesterol foods.
    • Previous studies suggest that adding eggs to the typical American diet may increase risk of cardiovascular disease and premature death.
    • In contrast, adding eggs to a primarily plant-based diet, such as found in China and Japan, appears to decrease risk of heart disease and premature death.

Red Meatfatty steak

Mechanisms: The mechanism(s) associated with the bad effects of red meat are less clear. Here are the potential mechanisms discussed by the authors of this study.

  • Red meat is high in cholesterol. While many experts have downplayed the importance of dietary cholesterol in recent years, it still may be of concern in the context of the typical American diet because of our body’s inability to regulate cholesterol metabolism normally.
  • Red meat is high in saturated fat. While some experts have downplayed the importance of reducing saturated fat intake, I pointed out in a previous issue of “Health Tips From the Professor” that it depends on what the saturated fat is replaced with.
    • When saturated fats are replaced with sugar and refined carbohydrates in the typical American diet, reducing saturated fat is of no benefit.
    • When saturated fats are replaced with polyunsaturated fats in the context of a primarily plant-based diet, such as the Mediterranean diet, reducing saturated fats leads to a substantial reduction in the risk of heart disease and premature death.
  • Red meat also contains heme iron which is associated with 57% increased risk of cardiovascular disease.
  • Diets high in red meat result in populations of gut bacteria that are associated with increased risk of cardiovascular disease. This is most likely because red meat is displacing plant foods that support the growth of healthy bacteria.
  • As discussed in a recent issue of “Health Tips From the Professor”, the gut bacteria associated with red meat consumption convert the L-carnitine in red meat to a metabolite called trimethylamine N-oxide (TMAO) which appears to significantly increase the risk of cardiovascular disease.
  • Finally, a recent study suggests that foods high in sulfur-containing amino acids significantly increase risk of cardiovascular disease. However, this mechanism is not specific for red meat. White meat, beans, and legumes are also high in sulfur-containing amino acids.

Perspective:

  • While the exact mechanism(s) is/are uncertain, there is substantial evidence from multiple studies that red meat consumption increases the risk of premature death from cardiovascular disease and from all causes.
  • Grass fed beef is not a “get out of jail free card”. Grass fed beef is modestly lower in cholesterol and saturated fat. However, those are only two of six potential mechanisms for the link between red meat consumption and cardiovascular disease.
  • However, those of you who, like me, enjoy red meat should not consider this to be an absolute “red meat should never touch your lips” edict. As I have discussed in a previous issue of “Health Tips From the Professor”, the health effects of red meat are a matter of quantity and diet context.
    • If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat is probably not a healthy choice.
    • However, if you are thinking of 2-3 ounces of lean steak in a vegetable stir fry or a green salad, red meat may be a healthier choice.

dairy products and heart diseaseDairy: I have reported on the health risks and benefits of dairy foods in a previous issue of “Health Tips From the Professor”, so I will just give you a brief summary here.

Perspective:

  • Eating dairy foods, even high-fat dairy foods, has relatively little effect on cardiovascular disease risk in the context of the typical high-fat, high-sugar American diet.
  • Eating dairy foods, even high-fat dairy foods, in the context of a healthy plant-based diet appears to lower cardiovascular disease risk.
  • As this study suggests, moving towards a more plant-based diet by substituting some plant protein for dairy protein in the diet will also decrease your risk of cardiovascular disease

White Meat: This and previous studies suggest that white meat is less likely than red meat to increase the risk of cardiovascular disease and premature death. I have discussed the differences between red and white meat in a previous issue of “Health Tips From the Professor”. However, I can summarize the differences best here by going back to the mechanisms associated with the link between red meat and cardiovascular diseases and highlight those that do not apply to white meat.

Mechanisms:

  • Saturated fat. Many fish are much lower in saturated fat and are excellent sources of heart-healthy omega-3 fats. Chicken and turkey breast with the skin removed are also much lower in saturated fat than red meat.
  • Heme iron. Chicken breast is lower in heme iron than red meats.
  • TMAO. White meats contain 10-50 times less L-carnitine than red meats. Since L-carnitine is the precursor of TMAO, they are much less likely to cause TMAO production.

Why Do Plant Proteins Decrease Your Risk Of Premature Death?

Whole Grains: Whole grains have been much maligned in recent years. They have been lumped in with sugar and refined grains and have been added to everyone’s “naughty list”.

  • If you are following a low-carb diet, you are told to avoid all grains.
  • If you are following a Paleo diet, you are told our paleo ancestors ate no grains.
  • If you are trying to avoid lectins…you get the point.

That’s unfortunate, because whole grains are very healthy. In a recent issue of “Health Tips From the Professor” I shared a study showing that whole grain consumption reduced the risk of premature death from heart disease, cancer, and all causes. The current study shows essentially the same thing.

The only question is why whole grains are uniquely effective at decreasing premature death from cardiovascular disease and all causes in this study. Why aren’t all plant proteins equally effective? I will share both a suggested mechanism and perspective.

Mechanism:

  • In a recent issue of “Health Tips From The Professor” I reported a study showing that grains and a few other foods contain a unique type of fiber called resistant starch that suppress growth of the gut bacteria which convert L-carnitine to TMAO. This may be why whole grains are uniquely effective at reducing the risk of cardiovascular disease and premature death.
  • Some refined grains are also good sources of resistant starch. However, I don’t recommend them because they lack the antioxidants, vitamins, phytonutrients, and insoluble fiber found in whole grains.

Perspective:  

The fact no other plant protein source significantly reduced heart disease risk in this study is most likely an artifact of the study.

  • The study asked what happens when you change 15 grams of the protein in your diet from red meat protein to different kinds of plant protein. That question was easy to answer for grains because they are a major source of protein in the American diet. However, Americans don’t get enough protein from other high protein plant foods like beans and legumes or nuts and seeds to provide a statistically valid answer to that question.
  • However, all plant foods have their own health benefits. They are excellent sources of antioxidants and phytonutrients that provide heart health benefits.
  • In addition, each plant food provides a different blend of fibers and supports different populations of gut bacteria with different health benefits. For example, fiber from fruits and vegetables is associated with a lower risk of cancer.

What Does This Study Mean For You?

dairy products and heart disease questionsA recent study has shown that changing as little as 20% of the protein in our diet from animal protein to plant protein significantly reduces our risk of premature death from cardiovascular disease, stroke, and from all causes.

The effect of replacing 2 ounces of red meat, 1 egg, or 2 servings of dairy with an equivalent amount of plant protein was equally beneficial.

Previous studies show that diet context is important. A small amounts of animal protein in the context of a whole food, primarily plant-based diet is much less likely to cause harm and may provide benefit. For example:

  • Eggs are high in cholesterol but are also excellent sources of low-fat protein and nutrients that may be missing in a plant-based diet.
    • Previous studies suggest that adding eggs to the typical American diet may increase risk of cardiovascular disease and premature death.
    • In contrast, adding eggs to a primarily plant-based diet, such as found in China and Japan, appears to decrease risk of cardiovascular disease and premature death.
  • Dairy foods are high in saturated fat but are excellent sources of calcium, vitamin D, and other nutrients that may be missing in a plant-based diet.
    • Eating dairy foods, even high-fat dairy foods, has relatively little effect on cardiovascular disease risk in the context of the typical high-fat, high-sugar American diet.
    • Eating dairy foods, even high-fat dairy foods, in the context of a healthy plant-based diet appears to lower cardiovascular disease risk.
  • Red meat has multiple suggested mechanisms for it increasing the risk of death from cardiovascular disease. However, diet context still matters.
    • If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat is probably not a healthy choice.
    • However, if you are thinking of 2-3 ounces of lean steak in a vegetable stir fry or a green salad, red meat may be a healthier choice.
    • Grass fed beef should not be considered a “get out of jail free card”. Grass fed beef is modestly lower in cholesterol and saturated fat. However, those are only two of six potential mechanisms for the link between red meat consumption and cardiovascular disease.
  • White meat does not appear to affect your risk of developing cardiovascular disease.
  • Whole grains significantly decreased the risk of premature death from cardiovascular disease and death from all causes. This may be because whole grains contain a unique type of fiber called resistant starch that suppresses the growth of the gut bacteria which convert L-carnitine to a heart-damaging compound called TMAO.
    • Notice that I specified “whole grain”. While some refined grains are also a good source of resistant starch, they lack the other heart healthy nutrients and phytonutrients found in whole grains.
      • Wonder Bread, Frosted Flakes, Honey Bunches of Oats, and white-flour pasta are not on my approved list. I agree with low-carb enthusiasts about eliminating them from our diets.
      • You should also be aware that “whole grain” on the label means nothing. You want to choose foods that say “100% whole grain”.
    • Finally, this study only focused on plant protein sources. It is important to remember that other plant foods are an excellent source of antioxidants, phytonutrients, and fiber. Each plant food provides unique heart health benefits.

The Bottom Line

A recent study has shown that changing as little as 20% of the protein in our diet from animal protein to plant protein significantly reduces our risk of premature death from cardiovascular disease, stroke, and from all causes.

The effect of replacing 2 ounces of red meat, 1 egg, or 2 servings of dairy with an equivalent amount of plant protein was equally beneficial. White meat did not affect the risk of cardiovascular disease or premature death.

  • Grass fed beef should not be considered a “get out of jail free card”. Grass fed beef is modestly lower in cholesterol and saturated fat. However, those are only two of six potential mechanisms for the link between red meat consumption and cardiovascular disease.
  • Diet context is important. Small amounts of animal protein in the context of a whole food, primarily plant-based diet appear to be much healthier for us than large amounts of animal protein in the context of the high-fat, high-sugar American diet.

On the flip side of the equation, whole grains significantly decreased the risk of premature death from cardiovascular disease and death from all causes. This has also been seen in other recent studies.

  • Notice that I specified “whole grain”. Wonder Bread, Frosted Flakes, Honey Bunches of Oats, and white-flour pasta are not on the list.
  • You should also be aware that “whole grain” on the label means nothing. You want to choose foods that say “100% whole grain”.
  • Finally, this study only focused on plant protein sources. It is important to remember that other plant foods are an excellent source of antioxidants, phytonutrients, and fiber. Each plant food provides unique heart health benefits.

For more details, read the article above, especially the “What Does This Study Mean For You?” section.

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.

What Is The Truth About Eating Eggs And Heart Disease?

Have The Dangers Of Eggs Been “Eggagerated”?

egg confusionIt’s no wonder you are confused about whether or not eggs are good for you. The advice you have been given about eggs over the years has been constantly changing.

Eggs are an affordable source of high-quality protein, iron, unsaturated fats, phospholipids like lecithin and choline, and carotenoids. That almost qualifies them as a health food. However, they are also a major source of cholesterol in the American diet. Back when we thought of dietary cholesterol was bad for us, that made eggs the enemy.

Then we discovered that dietary cholesterol has relatively little effect on blood cholesterol levels. It was obesity plus saturated fat and sugar in our diet that raised blood cholesterol levels and increased our risk of heart disease.

Then several studies reported that eggs did not increase our risk of heart disease. A study out of China even found that eggs decreased the risk of heart attack and hemorrhagic stroke. Suddenly, eggs became our best friend.

That only lasted a few years until a study from the United States reported that eggs increased your risk of heart disease, and a study from Europe reported that eggs increased your risk of hemorrhagic stroke. Eggfusion (egg confusion) reigned.

Most of these studies were large studies. They followed their participants for 5-10 years. Why were their results so confusing? A careful analysis of the studies shows that most of them suffered from three major weaknesses.

  • They only measured egg consumption at the beginning of the study. This fails to account for the fact that egg consumption has waxed and waned over the years as eggs have gone from enemy to friend and back to enemy.
  • They did not assess how the overall diet influences the effect of egg consumption on heart disease. If we believe the previous studies, eggs lower the risk of heart disease and hemorrhagic stroke in China and increase the risk of both in the United States and Europe. This suggests that overall diet is important, but this hypothesis has not been tested.
  • They also did not address the question of whether eggs, because of their cholesterol, might have a more adverse effect on heart disease in individuals who already have high blood cholesterol and have difficulty controlling their cholesterol levels.

That is why the study (JP Drouin-Chartier et al, British Medical Journal, 368:m513, 2020) I am reporting on today is so important. It is a huge study, much larger than any previous study on the topic. Plus, it was designed in such a way that it had none of the weaknesses of previous studies.

How Was The Study Done?

Clinical StudyThis study started by combining the data from three major clinical trials:

  • The first Nurse’s Health Study, which ran from 1980 to 2012,
  • The second Nurse’s Health Study, which ran from 1991-2013, and
  • The Health Professional’s Follow-Up Study, which ran from 1986-2012.

These studies combined enrolled 173,563 women and 42,055 men and followed them for an average of 32 years. All the participants were free of heart disease, type 2 diabetes, and cancer at the time they were enrolled. The design of these studies was extraordinary.

  • A detailed food frequency questionnaire was administered every 2-4 years. This allowed the investigators to calculate cumulative averages of all dietary variables, including egg intake. This assured that the effects of egg consumption and diet represented the participant’s diet over the 32-year duration of the study.
  • Participants also filled out questionnaires that captured information on disease diagnosis, disease risk factors, medicines taken, weight, and lifestyle characteristics every 2 years with follow-up rates >90%. This allowed the investigators to measure the onset of disease and medicine use for each participant during the study. More importantly, 32 years is long enough to measure the onset of diseases like heart disease, diabetes, and cancer – diseases that require decades to develop.
  • The endpoint of the study was “incident heart disease”, which the investigators defined as non-fatal heart attack, death from heart disease, and fatal and non-fatal stroke. During this study, 14,806 participants developed incident heart disease. This was a large enough number for a detailed statistical analysis of the data.
  • For example, statistical analysis showed that the participants with the highest egg intake also were more likely to be obese and more likely to consume red meat, bacon and other processed meats, refined grains, French fries, and sugar-sweetened beverages. These are what we refer to as “confounding variables” because they also increase the risk of heart disease and are likely to confound (confuse) the analysis. Therefore, the investigators statistically corrected the data on egg consumption for these confounding variables. Many previous studies did not have the data or statistical power to correct their egg consumption data for these confounding variables.

In short, this study was much larger, ran far longer, and was better designed that any of the previous studies on egg consumption and heart disease risk. However, the authors did not stop there. They also performed a meta-analysis of 28 previous studies with a total of 1,720,108 participants and 139,195 cardiovascular disease events.

The only weakness in this study is that only 2% of the participants ate more than one egg per day. Consequently, it cannot address the health consequences of eating more than one egg per day on a regular basis.

Before sharing the results of this study with you, I need to provide some background about how our bodies regulate blood cholesterol levels. So, let’s move on to my favorite topic, “Biochemistry 101”.

Biochemistry 101: Cholesterol Metabolism

ProfessorMost people think of cholesterol only as a bad thing – something that can kill us. Nothing could be further from the truth. In fact, cholesterol is essential for life.

  • Our body makes vitamin D and coenzyme Q10 from cholesterol.
  • Our body makes steroid hormones such as cortisol, estrogen, and testosterone from cholesterol.
  • Cholesterol is a vital component of the myelin sheath that coats our nerve cells.
  • And that is just the beginning.

Because cholesterol is essential, our body makes its own cholesterol and has an elegant control system that keeps our blood cholesterol levels right where they should be.

  • When we get lots of cholesterol from our diet, our body makes less and excretes any excess.
  • When we get little cholesterol from our diet, our body makes more and excretes less.

Unfortunately, many Americans muck up this elegant control system. There are several factors that can throw our body’s ability to regulate blood cholesterol levels out of whack, leading to elevated blood cholesterol levels and increased risk of heart disease. For example:

  • Obesity
  • Type 2 diabetes
  • Diets high in saturated fats
  • Diets high in sugar and refined carbohydrates
  • Genetics

And it’s not just elevated cholesterol that is the problem. These same factors are associated with inflammation, which also increases the risk of heart disease.

Of course, we can’t do anything about our genetics, but the other factors are under our control. Let’s keep that in mind as we look at the results of this study.

What Is The Truth About Eating Eggs And Heart Disease?

the truth signWhen the investigators looked at their combined data from the Nurse’s Health Studies and the Health Professional’s Study:

  • There was no difference in heart disease outcomes for participants consuming an average of one egg/day and participants consuming less than one egg/month.
  • When the investigators examined heart attack and stroke separately, there was no difference in either outcome for participants consuming an average of one egg/day and participants consuming less than one egg/month.
  • As mentioned above the participants who consumed the most eggs weighed more; were less physically active; were more likely to be current smokers; and were more likely to consume red meat, processed meats, refined grains, potatoes (think French fries and potato chips), full fat milk, and sugar-sweetened beverages.
    • Without correcting for these factors eating one egg/day resulted in a 10% increase in heart disease risk.
    • After correcting for these factors, eating one egg/day resulted in a 7% decrease in heart disease risk.
    • In both cases the differences were statistically non-significant. However, they were in line with the previous studies mentioned above.

When they looked at the data generated by their meta-analysis of 28 studies:

  • There was no association between heart disease risk and egg consumption.
    • In Asian countries where the diet was primarily unrefined, plant-based foods, egg consumption decreased heart disease risk.
    • In people with type 2 diabetes, egg consumption increased heart disease risk.

The authors concluded “…moderate egg consumption (up to one egg/day) is not associated with cardiovascular disease risk overall, and is associated with potentially lower cardiovascular disease risk in Asian populations.”

The authors also noted that their data did not allow them to evaluate the effect of consuming more than one egg/day.

Have The Dangers Of Eggs Been “Eggagerated”?

are eggs good for youThis study clears up a lot of confusion about egg consumption and heart disease risk. The problem is that the scientific and medical communities have been looking for a “one size fits all” recommendation about egg consumption. This study shows us that the reality is much more complicated. Let me describe my interpretation of the data.

I think the results of this and previous studies are best described by the phrase, Eggs are a healthy part of a healthy diet. Here is what I mean by that.

  • If you are consuming a primarily plant-based diet, your body is fully able to regulate your blood cholesterol levels. Then, you can reap the full benefits of the egg, namely the protein, iron, unsaturated fats, lecithin, choline, and carotenoids it provides. Under these conditions, eating up to one egg/day reduces your risk of heart disease.
  • If you are consuming a diet that contains primarily chicken or fish and unprocessed plant foods, egg consumption is neutral. It neither increases nor decreases your risk of heart disease.
  • If you are consuming a diet that contains sugar-sweetened beverages, red and processed meats, high fat dairy products, refined grains, and junk foods (ie, the typical American diet), your body is no longer able to regulate blood cholesterol levels well. Now the cholesterol content of eggs becomes an issue and consuming one egg/day slightly increases your risk of heart disease.
  • If you are overweight and have developed type 2 diabetes, your body has become insulin resistant. This also interferes with your body’s ability to regulate blood cholesterol levels. In this situation, consuming one egg/day also increases your risk of heart disease.

The caveat is, of course, that these conclusions are based averages, and none of us are average.

The Bottom Line

You are probably aware that the effect of egg consumption on heart disease risk is controversial. Some studies report that egg consumption has no effect on heart disease risk. Other studies report egg consumption decreases heart disease risk. Still other studies report that egg consumption increases heart disease risk. No wonder you are confused.

A recent study has cleared up much of the confusion. This was not just another study. This study was much larger, ran far longer, and was better designed that any of the previous studies.

If you look at this and previous studies, it becomes clear that the effect of egg consumption on heart disease risk is strongly influenced by your overall diet and lifestyle.

  • If you are consuming a primarily plant-based diet, your body is fully able to regulate your blood cholesterol levels. Then, you can reap the full benefits of the egg, namely the protein, iron, unsaturated fats, lecithin, choline, and carotenoids it provides. Under these conditions, eating up to one egg/day reduces your risk of heart disease.
  • If you are consuming a diet that contains primarily chicken or fish and unprocessed plant foods, egg consumption is neutral. It neither increases nor decreases your risk of heart disease.
  • If you are consuming a diet that contains sugar-sweetened beverages, red and processed meats, high fat dairy products, refined grains, and junk foods (ie, the typical American diet), your body is no longer able to regulate blood cholesterol levels well. Now the cholesterol content of eggs becomes an issue and consuming one egg/day slightly increases your risk of heart disease.
  • If you are overweight and have developed type 2 diabetes, your body has become insulin resistant. This also interferes with your body’s ability to regulate blood cholesterol levels. In this situation, consuming one egg/day also increases your risk of heart disease.

In short, eggs are a healthy part of a healthy diet.

For more details, read the article above. You may also want to read the section “Biochemistry 101: Cholesterol Metabolism” to gain a better understanding of the mechanism behind these statements.

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

Can Vitamin C Prevent Heart Disease?

Where Should I Get My Vitamin C?

vitamin CThe vitamin C controversy continues. Some people call vitamin C a “miracle” nutrient. Others consider it little more than “fairy dust”. What is the truth?

Let’s look at the effect of vitamin C on heart disease risk as an example of why it is so difficult to resolve questions like this.

Association studies are ideal for measuring long-term effects of nutrient consumption on health outcomes. These studies have consistently found an inverse association between dietary vitamin C and plasma vitamin C levels with the risk of heart disease. Simply put, the more vitamin C from dietary sources, the lower the risk of heart disease.

However, association studies do not prove cause and effect. The primary reason for this is that association studies are complicated by “confounding variables”. For example, most vitamin C in the diet comes from fruits and vegetables. So, the question arises, “Is it the vitamin C in fruits and vegetables that is responsible for the decreased heart disease risk, or is it the fiber that is also present in fruits and vegetables?” Previous studies have not been designed to answer this question.

Placebo-controlled clinical trials solve the confounding variable issue because they involve supplementation with pure vitamin C or a placebo. There is only a single variable. However, placebo-controlled clinical trials only last for a short time. That means they can measure biological markers that may affect heart disease risk but seldom last long enough to directly measure the effect of vitamin C on heart disease risk.

For example, previous studies have shown that high-dose (500 to 4,000 mg/day) supplementation with vitamin C improves the function of the endothelial lining of our blood cells and reduces blood pressure. These are biological markers that might be expected to reduce heart disease risk.

However, heart disease takes decades to develop. No studies of vitamin C supplementation have lasted long enough to show an actual decrease in heart disease outcomes.

In today’s issue of “Health Tips From The Professor” I would like to address three questions:

1) Does dietary vitamin C reduce heart disease risk?

2) How much of the risk reduction is due to the fiber content of fruits and vegetables rather than their vitamin C content?

3) Does supplementation with vitamin C reduce heart disease risk?

I will focus on a recent study (N Martin-Calvo and MA Martinez-Gonzalez, Nutrients, 9: 954, 2017, doi.org/10.3390/nu909054) that was designed to answer these questions.

How Was The Study Done?

Heart Health StudyThis study was an offshoot of an ongoing Spanish research program called Seguimiento Universidad de Navarra (SUN) follow-up study. This program is following graduates of the University of Navarra to gauge the effect of diet and lifestyle on health outcomes.

Health, lifestyle, and diet information is collected when graduates enroll in the program and by mailed questionnaires every two years thereafter.

Graduates who were enrolled in the SUN program in 2014 or earlier were invited to participate in this vitamin C and heart disease study.

  • Vitamin C intake from diet and from supplements was assessed from the dietary analysis.
  • A diagnosis of heart disease was obtained from the Health questionnaire and confirmed by physician follow-up.
  • Deaths due to heart disease were obtained from the Spanish National Death Index cross-referenced to participants in the study and were confirmed by participants next of kin, work associates, or postal authorities.

The study excluded:

  • Participants with pre-existing heart disease at the beginning of the study.
  • Participants who were younger than 40 at the beginning of the study.
  • Participants with either very high or very low vitamin C intake.

That left 13,421 participants who were young (average age = 42), at a healthy weight (average BMI = 24), healthy, and taking few medications.

Can Vitamin C Prevent Heart Disease?

Healthy HeartThe 13,421 participants in this study were followed for an average of 11 years.

They were divided into three groups based on their vitamin C intake.

  • Group 1 averaged 148 mg/day.
  • Group 2 averaged 257 mg/day.
  • Group 3 averaged 445 mg/day.

There are two noteworthy observations about their vitamin C intake:

  • None of the groups were vitamin C deficient. All three groups were getting well above the RDA for vitamin C (75 mg/day for women and 90 mg/day for men).
  • Most of the vitamin C came from fruits and vegetables in the diet. The group with the highest vitamin C intake (445 mg/day) only averaged about 10 mg/day from supplements.

The results of the study were intriguing. When the investigators compared the group with the highest vitamin C intake to the group with the lowest vitamin C intake:

  • Vitamin C significantly decreased both the risk of developing heart disease and the risk of dying from heart disease.
    • Statistically adjusting the data for age, gender, weight, lifestyle, and medicine use did not affect the outcome.
    • Statistically adjusting the data for fiber from sources other than fruits and vegetables did not affect the outcome.
    • Statistically adjusting the data for adherence to a healthy diet (the Mediterranean diet) did not affect the outcome.

However, when the data were statistically adjusted for total fiber (including fiber from fruits and vegetables) the high fiberresults painted a slightly different picture. With this adjustment:

  • Vitamin C decreased the risk of developing heart disease by 26%, but this decrease was not statistically significant.
  • Vitamin C decreased the risk of dying from heart disease by 70%, and this decrease was highly significant.

This was the first study to consider the relative importance of vitamin C from fruits and vegetables and fiber from fruits and vegetables on heart disease outcomes and the results were interesting. Here are the important conclusions.

1) Both the fiber and the vitamin C from fruits and vegetables contributed to a decreased risk of developing heart disease. This study was unable to separate their contributions.

Of course, it is important to note that this was a young, healthy population, none of whom were deficient in vitamin C. It would be interesting to repeat this study with an older, sicker population with a more restrictive diet.

2) Vitamin C from fruits and vegetables reduced the risk of dying from heart disease independent of the beneficial effects of fruit and vegetable fiber.

3) This study was not able to address the effect of vitamin C supplementation on heart disease risk. That is because the Spaniards supplement much less frequently than Americans and this study excluded anyone with unusually high vitamin C intake. The average supplemental vitamin C in the 3 groups ranged from 0.56 mg/day to 9.6 mg/day.

4) This study also emphasizes the importance of getting fiber from a variety of food sources. It showed that fiber from fruits and vegetables was more beneficial at reducing heart disease risk than fiber from other food sources. That means restrictive diets that eliminate fruits and/or vegetables may be bad for your heart.

Where Should I Get My Vitamin C?

Vegan FoodsThis study reinforces the importance of getting lots of fresh fruits and vegetables in your diet.

  • You could make a list of all the vitamin C-rich fruits and vegetables like citrus fruits, red & green peppers, broccoli, etc. and make sure you are including them in your diet.
  • You could total up the vitamin C in each food you eat and try to reach the 445 mg/day in the group with the highest vitamin C in this study.

However, it doesn’t have to be that complicated. If you eat a primarily plant-based diet, aim for 5-9 servings of fruits and vegetables a day, and “eat the rainbow” you will get plenty of vitamin C from your diet.

Also, don’t worry about whether the benefits of fruit and vegetable consumption come from their vitamin C or from their fiber. That’s the beauty of eating whole foods. You get both in the same package.

Of course, you are probably also wondering whether vitamin C supplementation will reduce your risk of heart disease. As I described earlier, there are lots of reasons for thinking that vitamin C supplementation might decrease heart disease risk.

  • Several studies show that higher vitamin C intake and higher vitamin C levels in the blood are associated with lower heart disease risk.
  • This study showed that vitamin C reduces the risk of dying from heart disease independent of fiber from fruits and vegetables and independent of an overall healthy diet. This suggests that vitamin C plays an independent role in reducing heart disease risk.
  • Placebo controlled clinical trials show that vitamin C supplementation reduces risk factors that contribute to heart disease.

However, none of these studies prove that vitamin C supplementation reduces heart disease risk. That requires placebo-controlled clinical trials measuring the effect of vitamin C supplementation on heart disease outcomes. Unfortunately, these studies are usually doomed to failure.

Chronic diseases like heart disease takes decades to develop. Placebo-controlled, randomized studies are almost never large enough or last long enough to show an effect of supplementation on chronic diseases.

The best we can say at present is that vitamin C supplementation along with a primarily plant-based diet with lots of colorful fruits and vegetables may reduce your risk of heart disease.

The Bottom Line

A recent study in Spain followed 13,421 healthy college graduates with an average age of 42 for 11 years and looked at the effect of vitamin C intake on the risk of developing heart disease and the risk of dying from heart disease.

This was the first study to consider the relative importance of vitamin C from fruits and vegetables and fiber from fruits and vegetables on heart disease outcomes and the results are intriguing. Here are the important conclusions.

1) Both the fiber and the vitamin C from fruits and vegetables contributed to a decreased risk of developing heart disease. This study was unable to separate their contributions.

Of course, it is important to note that this was a young, healthy population, none of whom were deficient in vitamin C. It would be interesting to repeat this study with an older, sicker population with a more restrictive die

2) Vitamin C from fruits and vegetables reduced the risk of dying from heart disease by 70%, and this effect was independent of the beneficial effects of fruit and vegetable fiber.

3) This study was not able to address the effect of vitamin C supplementation on heart disease risk. That is because the Spaniards supplement much less frequently than Americans and this study excluded anyone with unusually high vitamin C intake. The average supplemental vitamin C in the 3 groups ranged from 0.56 mg/day to 9.6 mg/day.

4) This study also emphasizes the importance of getting fiber from a variety of food sources. It showed that fiber from fruits and vegetables was more beneficial at reducing heart disease risk than fiber from other food sources. That means restrictive diets that eliminate fruits and/or vegetables may be bad for your heart.

For more details 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.

Should I Avoid Whole Grains?

Will Whole Grains Kill Me?

Whole GrainsIt seems like just yesterday that health experts all agreed that whole grains were good for us. After all:

  • They are a good source of fiber, B vitamins, vitamin E, and the minerals magnesium, iron, zinc, manganese, and selenium.
  • Their fiber fills you up, so you are less likely to overeat. This helps with weight control.
  • Their fiber also supports the growth of friendly bacteria in your gut.

In fact, the USDA still recommends that half of the grains we eat should be whole grains. And, outside experts, not influenced by the food industry, feel this recommendation is too low. They feel most of the grains we eat should be whole grains. Foods made from refined grains should be considered as only occasional treats.

Then the low-carb craze came along. Diets like Paleo and Keto were telling you to avoid all grains, even whole grains. Even worse, Dr. Strangelove and his colleagues were telling you whole grains contained something called lectins that were bad for you. Suddenly, whole grains went from being heroes to being villains.

You are probably asking, “Should I avoid whole grains?” What is the truth? Perhaps the best way to resolve this debate is to ask, how healthy are people who consume whole grains for many years? This week I share a recent study (G Zong et al, Circulation, 133: 2370-2380, 2016) that answers that very question.

How Was The Study Done?

This study was a meta-analysis of 14 clinical trials that:

  • Enrolled a total of 786,076 participants.
  • Obtained a detailed diet history at baseline.
  • Followed the participants for an average of 15 years (range = 6-28 years).
  • Determined the effect of whole grain consumption on the risk of death from heart disease, cancer, and all causes.

Will Whole Grains Kill Me?

deadDr. Strangelove and his colleagues are claiming that whole grains cause inflammation, which increases your risk of heart disease and cancer. Heart disease and cancer are the leading causes of death in this country. In fact, according to the CDC, heart disease and cancer accounted for 44% of all deaths in the US in 2017.

Therefore, if Dr. Strangelove and his colleagues were correct, consumption of whole grains should increase the risk of deaths due to heart disease and cancer – and increase the risk of death due to all causes.

That is not what this study showed.

When the highest whole grain intake (5 servings/day) was compared with the lowest whole grain intake (0 servings/day), whole grain consumption reduced the risk of death from:

  • Heart disease by 18%.
  • Cancer by 12%.
  • All causes by 16%.

Furthermore, the effect of whole grains on mortality showed an inverse dose response. Simply put, the more thumbs upwhole grains people consumed, the lower the risk of deaths from heart disease, cancer, and all causes.

However, the dose response was not linear. Simply going from 0 servings of whole grains to one serving of whole grains reduced the risk of death from.

  • Heart disease by 9%.
  • Cancer by 5%.
  • All causes by 7%.

The authors concluded: “Whole grain consumption was inversely associated with mortality in a dose-response manner, and the association with cardiovascular mortality was particularly strong and robust. These observations endorse current dietary guidelines that recommend increasing whole grain intake to replace refined grains to facilitate long-term health and to help prevent premature death.”

The authors went on to say: “Low-carbohydrate diets that ignore the health benefits of whole grain foods should be adopted with caution because they have been linked to higher cardiovascular risk and mortality.”

Should I Avoid Whole Grains?

Question MarkAs for the original question, “Should I avoid whole grains?”, the answer appears to be a clear, “No”.

The strengths of this study include the large number of participants (786,076) and the demonstration of a clear dose-response relationship between whole grain intake and reduced mortality.

This study is also consistent with several other studies that show whole grain consumption is associated with a lower risk of heart disease, diabetes, cancer – and appears to lead to a longer, healthier life.

In short, it appears that Dr. Strangelove and the low-carb enthusiasts are wrong. Whole grains aren’t something to avoid. They reduce the risk of heart disease, diabetes, and cancer. And they reduce the risk of premature death. We should be eating more whole grains, not less.

However, the authors did point out that this study has some weaknesses:

  • It is an association study, which does not prove cause and effect.
  • Study participants who consumed more whole grains also tended to consume more fruits and vegetables – and less red meat, sodas, and highly processed foods.

However, I would argue the second point is a strength, not a weakness. We need to give up the idea that certain foods or food groups are “heroes” or “villains”. We know that primarily plant-based diets like the Mediterranean and DASH diets are incredibly healthy. Does it really matter how much of those health benefits come from whole grains and how much comes from fruits and vegetables?

The Bottom Line

Dr. Strangelove and low-carb enthusiasts have been telling us we should avoid all grains, including whole grains. Is that good advice?

If Dr. Strangelove and his colleagues were correct, consumption of whole grains should increase the risk of deaths due to the top two killer diseases, heart disease and cancer. Furthermore, because heart disease and cancer account for 44% of all deaths in this country, whole grain consumption should also increase the risk of death due to all causes.

A recent study showed the exact opposite. The study showed:

When the highest whole grain intake (5 servings/day) was compared with the lowest whole grain intake (0 servings/day), whole grain consumption reduced the risk of death from:

  • Heart disease by 18%.
  • Cancer by 12%.
  • All causes by 16%.

Furthermore, the effect of whole grains on mortality showed an inverse dose response. Simply put, the more whole grains people consumed, the lower the risk of deaths from heart disease, cancer, and all causes.

However, the dose response was not linear. Simply going from 0 servings of whole grains to one serving of whole grains reduced the risk of death from.

  • Heart disease by 9%.
  • Cancer by 5%.
  • All causes by 7%.

The authors concluded: “Whole grain consumption was inversely associated with mortality in a dose-response manner, and the association with cardiovascular mortality was particularly strong and robust. These observations endorse current dietary guidelines that recommend increasing whole grain intake to replace refined grains to facilitate long-term health and to help prevent premature death.”

The authors went on to say: “Low-carbohydrate diets that ignore the health benefits of whole grain foods should be adopted with caution because they have been linked to higher cardiovascular risk and mortality.”

For more details 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.

Omega 3 Supplementation And Heart Disease Risk

How Can You Reduce Your Risk Of Heart Disease?

fish and fish oilI understand your confusion. One month the headlines say that omega 3 supplementation reduces the risk of heart disease. The next month headlines claim that omega 3 supplements are worthless. What is the truth about omega 3 supplementation and heart disease risk?

Let me start by sharing the two of the most recent studies on the topic. They are both very large, well designed studies. However, the reason I selected these two studies is that they approached the relationship between omega 3 supplementation and heart disease risk in very different ways but came to the same conclusion.

The first study (Y Hu et al, Journal of the American Heart Association, Volume 8, Issue 19, 1 October 2019) was a meta-analysis of 13 randomized controlled clinical studies looking at the relationship between omega 3 supplementation and heart disease risk.

The second study (Z-H Li et al, British Medical Journal, BMJ2020;368:m456) looked at the association between habitual omega 3 supplementation and heart disease risk.

Each of these studies had strengths and weaknesses, but they complemented each other. The weaknesses of one study were the strengths of the other study.

How Were The Studies Done?

Clinical StudyStudy #1: The 13 studies included in the meta-analysis had a total of 127,477 participants (mean age 64, 60% male, mostly overweight) who were given either an omega-3 supplement or a placebo.

  • 40% of the participants had diabetes.
  • 72% of the participants were on cholesterol lowering drugs and a variety of other medications.
  • Participants were followed for between 3 and 7.4 years (average follow-up period was 5 years).
  • The dose of omega 3s ranged between 376 and 4,000 mg/day.

The major strengths of this study were:

  • All 13 studies included in the meta-analysis were randomized, placebo controlled clinical trials.
  • The meta-analysis had a very large number of participants (nearly 130,000), so it was possible to accurately measure even small effects of omega 3 supplementation on heart disease risk.

The major weaknesses of this study were:

  • Most of the participants were already on multiple drugs that provided many of the same benefits as omega 3s, so it was impossible to assess the full effect of omega 3 supplementation on heart disease risk.
  • The duration of the clinical trials included in this meta-analysis was short compared to the decades required for heart disease to develop.
  • Most of the participants already had heart disease or were at high risk of developing heart disease. The people in these studies were not representative of the general population.

Study #2: The data for this study were obtained from the UK Biobank study which enrolled 427,678 participants (mean age 56, 45% male) from 22 medical centers across England, Scotland, and Wales. None of the participants had been diagnosed with heart disease or cancer at the time of enrollment.

At enrollment the participants filled out a detailed online questionnaire concerning their lifestyle, diet, diseases, medications, and supplement use. Among the questions was whether they habitually used fish oil supplements (Yes or No).

  • The participants were enrolled between 2006 and 2010 and followed for an average of 9 years.
  • 31% of the participants were already taking omega 3 supplements on a regular basis at the time they enrolled in the study. This was the omega 3 supplementation group. The remaining 69% was the control group.
  • Only 10% of the participants were taking statin drugs or aspirin, probably because none of them had been diagnosed with heart disease.
  • Around 10% of the participants had high blood pressure and were taking blood pressure medications.
  • Most of the participants were slightly overweight but only 4% had diabetes.

The main strengths of this study were:

  • Very few of the participants were on medications. That means that medications did not interfere with the effect of omega 3 supplementation.
  • The participants were already using omega 3 supplements at the time of enrollment and were followed for an additional 9 years. That means that the duration of omega 3 supplement use was much longer than in the first study.
  • The participants were healthy and free of heart disease at the beginning of the study. That means that the results of this study focused more on prevention than on treatment. It also means the results are more applicable to the general population.

The main weakness of this study was:

  • It was an association study, which cannot prove cause and effect. In contrast, the first study was based on randomized, placebo controlled clinical trials, which can prove cause and effect.

In short, the weaknesses of the first study were strengths of the second study and vice-versa.

Omega 3 Supplementation And Heart Disease Risk

strong heartStudy #1: The results from the meta-analysis of randomized, placebo-controlled clinical trials were that omega 3 supplementation:

  • Reduced heart attacks by 12%.
  • Reduced overall heart disease risk by 7%.
  • Reduced deaths from heart disease by 8%.
  • Because of the large number of participants included in the meta-analysis, all these reductions were highly significant.
  • The risk reduction was linearly related to the dose of omega-3s, but the study did not allow estimation of an optimal omega-3 dose.

The authors concluded: “Marine [fish oil] omega-3 supplementation lowers risk for heart attack, overall heart disease risk, and heart disease death…Risk reductions appear to be linearly related to marine omega-3 dose.”

Study #2: This study showed that regular use of omega-3 supplements:

  • Reduced deaths from all causes by 13%.
  • Reduced deaths from heart attacks by 20%.
  • Reduced deaths from all types of heart disease by 16%.
  • Because of the large number of participants, all these reductions were highly significant.
  • This study did not collect data on omega-3 dose, so the study did not allow estimation of an optimal omega-3 dose.

The authors concluded: “Habitual use of fish oil seems to be associated with a lower risk of all cause mortality and heart disease mortality…,supporting their use for the prevention of mortality from all causes and heart disease. Future studies are needed to examine the extent to which the dose of fish oil supplements influences the ability to achieve a clinically meaningful effect.”

While these studies did not provide information on the optimal omega 3 dose, a previous study concluded that an omega-3 intake of 835 mg/day or higher is needed to achieve clinically meaningful reductions in heart disease risk.

How Can You Reduce Your Risk Of Heart Disease?

Heart Healthy DietThese two studies support the value of omega 3 supplementation for reducing heart disease risk. However, while risk reductions were highly significant, the magnitude of risk reduction was relatively small. That means we should think of omega-3 supplementation as part of a holistic approach to reducing our health disease risk. It is just one piece of the puzzle.

With that in mind, here is what the American Heart Association recommends for reducing your risk of heart disease:

  • If you smoke, stop.
  • Choose good nutrition.
    • Choose a diet that emphasizes vegetables, fruits, whole grains, low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts.
    • Choose a diet that limits sweets, sugar-sweetened beverages, and red meats.
  • Reduce high blood cholesterol and triglycerides.
    • Reduce your intake of saturated fat, trans fat and cholesterol and get moving.
    • If diet and physical activity don’t get those numbers under control, then medication may be the next step.
  • Lower High Blood Pressure.
  • Be physically active every day.Heart Healthy Exercise
    • Aim for at least 150 minutes per week of moderate-intensity physical activity per week.
  • Aim for a healthy weight.
  • Manage diabetes.
  • Reduce stress.
  • Limit alcohol.

Add in omega-3 supplementation to these recommendations and you have a winning combination.

The Bottom Line

Two major studies have recently been published on the relationship between omega 3 supplementation and heart disease. I felt it was important to evaluate these studies together because:

  • They are both very large, well designed studies.
  • They approached the relationship between omega 3 supplementation and heart disease risk in very different ways but came to the same conclusion.
  • They complemented each other. The weaknesses of one study were the strengths of the other study.

These studies showed that omega 3 supplementation:

  • Reduced heart attacks by 12-20%.
  • Reduced overall heart disease risk by 7%.
  • Reduced deaths from heart disease by 8-16%.
  • Reduced deaths from all causes by 13%

While these studies did not provide information on the optimal omega 3 dose, a previous study concluded that an omega-3 intake of 835 mg/day or higher is needed to achieve clinically meaningful reductions in heart disease risk.

For more details and the American Heart Association recommendations on what else you can do to reduce your risk of heart disease, 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.

Could A Probiotic Supplement Make You Healthier?

What Is The Truth About Our Microbiome?

Myth BusterOur gut bacteria, often referred to as our microbiome, are a “hot” topic in today’s world. They have been in the news a lot in recent years. If you believe the headlines, the right gut bacteria can make you smarter, healthier, and cure what ails you. They appear to have almost mystical powers. Could a probiotic supplement make you healthier?

How much of this is true and how much is pure speculation? It’s hard to say. Our microbiome is incredibly complex. To make matters more confusing, the terminology used to classify our gut bacteria into groups is not consistent. It varies from study to study.

Perhaps it is time to take an unbiased look at the data and separate fact from speculation.

Could A Probiotic Supplement Make You Healthier?

Probiotic SupplementTo answer the question of whether a probiotic supplement could make you healthier, we need to differentiate between what we know is true and what we think might be true. Let’s start with what we know for certain:

  • Our gut bacteria are affected by diet. People consuming a primarily plant-based diet have different populations of gut bacteria than people consuming a primarily meat-based diet.
    • The populations of gut bacteria found in people consuming a plant-based diet are associated with better health outcomes, but associations have their limitations as discussed below.
  • Our gut bacteria are affected by exercise.
    • It’s not clear whether it is the exercise or the fitness (increased muscle mass, decreased fat mass, improved metabolism) associated with exercise that is responsible for this effect.

Most of the other claims for the effects of gut bacteria on our health are based on associations. However, associations do not prove cause and effect. For example:

  • Certain populations of gut bacteria are associated with obesity.
    • Do our gut bacteria make us obese, or does obesity affect our gut bacteria? There is evidence to support both viewpoints.
  • Certain populations of gut bacteria are associated with better mental health.
    • Do gut bacteria influence mental health, or does the stress associated with poor mental health influence our gut bacteria? Again, there is evidence to support both viewpoints.
  • Certain populations of gut bacteria are associated with better health outcomes (reduction in diseases like heart disease, diabetes, and high blood pressure).
    • Here the question is a little different. In general, the populations of gut bacteria associated with disease reduction are produced by a healthy diet, exercise, and weight control. In this case, the question becomes: Is it the gut bacteria that caused disease reduction, or is it diet, exercise, and weight control that caused disease reduction?

To better understand these points, let’s look at four recently published studies. After reviewing those studies, I will come back to the question of whether a probiotic supplement might decrease our disease risk.

Is Our Microbiome Better Than Our Genes For Predicting Disease?

Predict DiseaseThis study (T. Tierney et al, bioRxiv, 2020) reviewed 47 studies that analyzed people’s microbiome (their gut bacteria) and their genes and asked which was better at predicting their risk of various diseases. The study focused on 13 diseases that are considered “complex” because they are caused by both genetic and environmental factors such as diet and exercise. Examples include diabetes, high blood pressure, digestive disorders, asthma, Parkinson’s disease, and schizophrenia.

The study found that our microbiome was a better predictor of these diseases than our genes. This finding is not surprising. Our microbiome is heavily influenced by diet and other environmental factors. Our DNA sequence is not.

This study supports previous studies in suggesting that our microbiome is a better predictor of most diseases than our DNA sequence. The exception would be diseases that are clearly caused by gene mutations, such as sickle cell disease.

Does this mean our microbiome is directly influencing these diseases, or is it merely serving as a marker for diet and other environmental factors that are influencing these diseases? Nobody knows.

Does The Mediterranean Diet Support Gut Bacteria Linked To Healthy Aging?

Mediterranean dietThis study ( TS Ghosh et al, Gut, 17 February 2020) divided people aged 65-79 into two groups. One group consumed a Mediterranean diet rich in fruits, vegetables, nuts, legumes, olive oil, and fish and low in red meat and saturated fat. The other group consumed a typical western diet. After a year on the diets the gut bacteria in the microbiomes of the two groups was analyzed.

The study found that the group consuming the Mediterranean diet had an increase in gut bacteria associated with healthy aging, reduced inflammation, and reduced frailty.

The title of the paper describing this study was “Mediterranean diet intervention alters the gut microbiome in older people, reducing frailty and improving health status”. But is that true?

There is already good evidence that the Mediterranean diet improves health status. Is it the gut bacteria supported by the Mediterranean diet that were responsible for healthy aging, or were other aspects of the Mediterranean diet responsible for healthy aging? Nobody knows.

Are Low Fat Diets Healthy Because Of Their Effect On Our Microbiome?

Heart Healthy DietThis study (Y Wang et al, Gut Microbes, 21 January 2020) put participants on a low fat diet (20% fat and 66% carbohydrates), a moderate fat diet (30% fat and 56% carbohydrate) or a high fat diet (40% fat, 46% carbohydrates). To assure the accuracy of the diets, participants were provided with all foods and beverages they consumed. After 6 months on the three diets, the gut bacteria of each group were analyzed.

Note: Because all food and beverages were provided, none of the diets included sodas, added sugar, refined flour, saturated fats, or highly processed food. In short, the diets were very different than the typical low fat or low carb diets consumed by the average American.

This study found that participants consuming the high fat, low carb diet had gut bacteria associated with increased risk of heart disease and diabetes. In contrast, the low fat, high carbohydrate diet group had gut bacteria associated with decreased risk of heart disease and diabetes.

To understand this study, you need to reevaluate what you may have learned from Dr. Strangelove’s health blog. It is true that low fat diets in which fat has been replaced with sugar, refined flour, and highly processed low-fat foods are unhealthy. But that’s not what happened in this study.

Remember that all the food and drink the participants consumed was selected by dietitians.

When you replace the fat with whole foods – fresh fruits and vegetables, whole grains, nuts, and legumes, as was done in this study, you end up with a very healthy diet.

The authors talked about the importance of the “diet-gut axis” for reducing the risk of heart disease and diabetes. However, is it the gut bacteria that influenced the risk of heart disease and diabetes, or is it the diets themselves that influenced disease risk? Nobody knows.

Can Gut Bacteria Reduce Heart Disease Risk?

MicrobiomeThis study (Y Heianza et al, Journal of The American College Of Cardiology, 75: 763-772, 2019) focused on the interactions between diet, gut bacteria, and a metabolite called TMAO (trimethylamine N-oxide).

Here is what we know for certain:

  • L-carnitine (found in high levels in red meat) can be converted to TMA (trimethylamine) by gut bacteria and then to TMAO in the liver.
  • The gut bacteria of meat eaters are very efficient at converting L-carnitine to TMA. Thus, meat eaters tend to have high levels of TMAO in their blood.
  • The gut bacteria of vegans and vegetarians are very inefficient at converting L-carnitine to TMA. Thus, people consuming a primarily plant-based diet tend to have low TMAO levels in their blood.

Here is what we are uncertain about:

  • High TMAO levels are associated with increased heart disease risk. However, there is no direct evidence that TMAO causes heart disease.

What made this study unique is that it measured TMAO levels in the study participants at their entrance into the study and again 10 years later. The study found:

  • Participants with the greatest increase in TMAO levels over the 10 years had a 67% increased risk of heart disease compared to participants whose TMAO levels remained constant.
  • Participants consuming a healthy, primarily plant-based diet had little or no increase in TMAO levels over 10 years. It was the participants consuming an unhealthy diet who had significant increases in their TMAO levels.

This study strengthens the association between TMAO levels and heart disease risk. Because gut bacteria are required to produce TMAO, it also strengthens the association between gut bacteria and heart disease risk. However, is it the high TMAO levels that increased heart disease risk or is it the unhealthy diet that increased heart disease risk? Nobody knows.

What Is The Truth About Our Microbiome?

MicrobiomeBy now you have probably noticed a common theme that runs through all four studies. This is also true of most published studies on our microbiome.

  • We have good evidence that whole food, primarily plant-based diets lead to improved long-term health outcomes.
  • We also have good evidence that whole food, primarily plant-based diets influence the populations of gut bacteria found in our microbiome.
  • We know the populations of gut bacteria supported by primarily plant-based diets are associated with improved health outcomes.
  • We don’t really know whether it is the gut bacteria or the diets that are responsible for the improved health outcomes.

Don’t misunderstand me. I am not a microbiome skeptic. I think we have enough evidence to say that our gut bacteria are likely to have an important effect on our health. However, to claim that gut bacteria play a primary role in influencing our health would be pure speculation at this point.

A Cautionary Tale

HDL CHolesterolWhy do I make this point? It’s because I suspect that some in the supplement industry will be tempted to make probiotic supplements and claim they contain bacteria “known” to reduce the risk of heart disease, diabetes, or cancer. You wouldn’t need to change your diet. All you would need to do to improve your health would be to take their probiotic supplement.

Lest you be taken in by such future claims, let me share a cautionary tale.

High HDL cholesterol levels are associated with a reduced risk of heart disease. Exercise and weight loss increase HDL levels. However, those require work. They aren’t easy. So, pharmaceutical companies were constantly looking for ways to raise HDL levels without the hard work.

A few years ago, a pharmaceutical company discovered a drug that increased HDL levels. They thought they had discovered a wonder drug that would bring in billions of dollars. People wouldn’t need to exercise. They wouldn’t need to lose weight. All they would need to do would be to take their drug. HDL levels would go up and heart disease risk would go down.

However, when they tested their drug in a major clinical trial, it didn’t move the needle. HDL levels went up, but heart disease risk stayed the same. It turns out it was the exercise and weight loss that decreased heart disease risk, not the increase in HDL levels.

My message is simple. Even if our gut bacteria are found to play a major role in mediating the effect of diet on health outcomes, don’t assume we can take a probiotic and forget about the role of diet and exercise. Good health starts with a whole food, primarily plant-based diet and a healthy lifestyle.

The Bottom Line

Our gut bacteria, often referred to as our microbiome, are “hot”. If you believe the headlines, the right gut bacteria can make you smarter, healthier, and cure what ails you. How much of this is true and how much is pure speculation? In this article I reviewed four recent studies on diet, gut bacteria, and health outcomes. I took an unbiased look at the data and separated fact from speculation.

There was a common theme that ran through all four studies. This is also true of most published studies on our microbiome.

  • We have good evidence that whole food, primarily plant-based diets lead to improved long-term health outcomes.
  • We also have good evidence that whole food, primarily plant-based diets influence the populations of bacteria found in our gut, also known as our microbiome.
  • We know the populations of gut bacteria supported by primarily plant-based diets are associated with improved health outcomes.
  • We don’t really know whether it is the gut bacteria or the diets that are responsible for the improved health outcomes.

Don’t misunderstand me. I am not a microbiome skeptic. I think we have enough evidence to say that our gut bacteria are likely to have an important effect on our health. However, to claim that gut bacteria play a primary role in influencing our health would be pure speculation at this point.

Why do I make this point? It’s because I suspect that some in the supplement industry will be tempted to make probiotic supplements and claim they contain bacteria “known” to reduce the risk of heart disease, diabetes, or cancer. You wouldn’t need to change your diet. All you would need to do to improve your health would be to take their probiotic supplement.

My message is simple. Even if our gut bacteria are found to play a major role in mediating the effect of diet on our health outcomes, don’t assume we can take a probiotic and forget about the role of diet and exercise. Good health starts with a whole food, primarily plant-based diet and a healthy lifestyle.

For more details, read the article above. You may be particularly interested in the cautionary tale I shared about HDL and heart disease risk.

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

Is Red Meat As Healthy As White Meat?

The Lies of the Beef Industry

Eating Red MeatLast week I wrote about a recent review claiming that the evidence for the health risks of red meat consumption was so weak that the best advice for the American public was to eat as much of it as they like. I pointed out the many flaws in that study.

  • One of the flaws was that the review discounted dozens of association studies showing a link between red meat consumption and disease and relied instead on randomized controlled trials. Normally, that would be a good thing, but…
  • The association studies looked at health outcomes and had hundreds of thousands of participants. They found clear links between red meat consumption and increased risk of heart disease and cancer.
  • The randomized controlled trials looked at blood parameters like LDL cholesterol and averaged less than 500 participants. These studies were too small to provide meaningful results, and, not surprisingly, the results were conflicting. Some linked red meat consumption to increased risk, while others did not.

Because they had discounted evidence from association studies, the authors of the review concluded that the overall evidence was weak.

This week I want to address why the evidence from randomized controlled trials for health risks of red meat is so weak. More importantly, I want to highlight the role of the beef industry in making sure the evidence on the health risks of red meat consumption is weak.

I will also point out the role of the media in this process because they are equally complicit in spreading misleading information about the health risks of red meat consumption.

You might be asking: “How does the beef industry influence clinical trials to produce outcomes supporting their message that red meat is perfectly healthy?” “Surely they can’t convince reputable scientists to falsify their results.”

  • The answer is they don’t need to convince scientists to falsify their results. They just need to influence the design of the experiments so the results will be to their liking.” I will give two examples of that in this article.

Next you might be wondering: “What is the role of the media in this? Surely they just report what the scientific publication says.” Don’t be deceived. The media isn’t interested in accuracy. They are interested in generating the largest possible audience. They know controversy attracts an audience. They are looking for “man bites dog” headlines even if it isn’t true.

  • If you actually read the studies, you discover that reputable scientists always discuss the weaknesses and flaws in their study. The media either doesn’t read the publication or ignores the weaknesses. Instead they focus on the most controversial headline they can craft. I will give some examples of that as well.

Is Red Meat As Healthy As White Meat?

Red Meat Vs White MeatFor years we have been told that red meat increases our risk of heart disease because it is high in saturated fats. We’ve been told that white meat and plant proteins are better alternatives.

But the latest headlines claim that red meat is just as heart healthy as white meat. You are probably wondering what to believe. Let’s examine the study behind the headline and ask two important questions?

  1. Did the beef industry influence the study?
  2. Did the media distort the study in their reporting?

I will start by reporting the study design and the results of the studies without comment. Then I will discuss how the beef industry influenced the design of the study to produce misleading results.

The Headlines Said: “Red Meat and White Meat Are Equally Heart Healthy.” The study behind the headlines was a 4-week study (N Bergeron et al, American Journal of Clinical Nutrition, 110: 24-33, 2019) comparing equivalent amounts of red meat, white meat, and non-meat protein on LDL levels. It did report that red meat and white meat raised LDL cholesterol levels to the same extent, but here is what the headlines didn’t tell you:

  • The authors of this study are heavily funded by the dairy and beef industries. I will point out the implications of this funding below.
  • 4 weeks is a very short time. This study provides no information on the long-term effects of red meat versus white meat consumption.
  • The study only measured LDL and related lipoproteins. It did not measure heart disease outcomes. LDL and lipoprotein levels are only one indicator of heart disease risk. Thus, they are imperfect predictors of heart disease risk. I will point out why that is important below as well.
  • The study was performed at two levels of saturated fat – low (7% of calories) and high (14% of calories).

At the low level of saturated fat, only the leanest cuts of red meat (top round and top sirloin) were used to keep saturated fat low in the red meat group. High fat dairy foods were added to the non-meat protein group to increase saturated fat content. Thus, all 3 groups consumed the same amount of saturated fat.

At the high level of saturated fat, butter and high-fat dairy foods were added to the white meat and non-meat protein groups to increase saturated fat content. Once again, saturated fat content was identical in all 3 groups.

Here were the results:High Cholesterol

  • LDL and related lipoproteins were higher for the high saturated fat group than the low saturated fat group. Nothing new here. This is consistent with dozens of previous studies. We know that saturated fat increases LDL cholesterol levels when other aspects of the diet are kept constant.
  • In both the low and high saturated fat groups, red and white meat raised LDL cholesterol to the same extent. In other words, when saturated fat levels are held constant, red meat and white meat raise cholesterol levels to the same extent.

In interpreting that statement, you need to remember the study design.

    • In the low saturated fat group, only two cuts of red meat were low enough in saturated fat for a direct comparison to white meat.
    • In the high saturated fat group, butter and high fat dairy had to be added to white meat so it could be compared to red meat.

Obviously, this is not the real world. 95% of the red meat the average American consumes is higher in saturated fat than most white meat.

The authors concluded “The findings…based on lipid and lipoprotein effects, do not provide evidence for choosing white over red meat for reducing heart disease risk”. That conclusion is clearly inaccurate.

  • The study did not measure heart disease outcomes. It measured only LDL cholesterol and related lipoprotein levels. That is just one factor in determining heart disease risk. The significance of that statement will be explained below.
  • Red meat and white meat raised LDL cholesterol levels to the same extent only when saturated fat is held constant. We know that most red meat is higher in saturated fat than white meat and saturated fat raises LDL cholesterol levels. In fact, the study confirmed that the high-fat red meats most people consume raised LDL cholesterol more than white meats.
  • The accurate conclusion to this study would have been: “Most red meat raises LDL cholesterol more than white meat, which suggests red meat may increase heart disease risk compared to white meat.”
  • Did I mention that the authors are heavily funded by the beef industry?

What About TMAO And Heart Disease Risk?

heart diseaseInterestingly, the authors also looked at another risk factor for heart disease in the same study, something called TMAO. I have discussed the relationship between red meat, TMAO, and heart disease risk in a previous issue of “Health Tips From the Professor”).

Let me summarize briefly here:

  • Red meat has 10-50-fold higher concentrations of a compound called L-carnitine than white meat.
  • Meat eaters have a very different population of gut bacteria than people who eat a primarily plant-based diet. It is not clear whether that is due to the meat or the loss of plant foods that meat displaces from the diet.
  • The gut bacteria of meat eaters convert L-carnitine to trimethylamine (TMA), which the liver then converts to trimethylamine N-oxide (TMAO).
  • The gut bacteria of people consuming a primarily plant-based do not convert L-carnitine to TMA, so no TMAO is formed. For example, in one study investigators fed an 8-ounce sirloin steak to meat eaters and to vegetarians. The meat eaters ended up with high levels of TMAO in their blood. The vegetarians had little or no TMAO in their blood.
  • High levels of TMAO are associated with atherosclerosis, increased risk of heart attacks, and death. Therefore, TMAO is considered an independent risk factor for heart disease.

The authors of the study comparing red meat and white meat also found that blood TMAO levels were two-fold higher in the red meat group than in the other two groups and this was independent of dietary saturated fat. However, rather than publishing this in the same paper where it might have interfered with their message that red and white meat affect heart disease risk to the same extent, the authors chose to publish these data in a separate paper (Z.Wang, European Heart Journal, 40: 7: 583-594, 2018).

Did I mention the authors are heavily funded by the beef industry?

Is Red Meat Healthy As Part Of A Mediterranean Diet?

Mediterranean Diet FoodsLet me briefly touch on one other study funded by the beef industry. The headlines said: “You may not have to give up red meat. It is healthy as part of a Mediterranean diet.”

The study (LE O’Connor et al, American Journal of Clinical Nutrition, 108: 33-40, 2018) behind the headlines did report that lean beef and pork did not raise LDL cholesterol levels when they were included in a Mediterranean diet. However, it is important to look at what the headlines didn’t tell you.

  • The red meat group consumed only 2.4 ounces of red meat a day. We aren’t talking about 8-ounce steaks or a rack of pork ribs here.
  • The red meat group ate only the very leanest (tenderloin) cuts of beef or pork.
  • On a positive note, while it wasn’t measured in this study, it is likely that TMAO levels would be relatively low because the subjects were consuming a primarily plant-based diet. They were consuming 7 servings of vegetables, 4 servings of fruit, and 4 servings of whole grains each day.
  • Similarly, red meat has several components that appear to increase cancer risk. However, they can be largely neutralized by various plant foods. This is something I have discussed in more detail in my book “Slaying The Food Myths”.

In summary, it would have been more accurate to conclude that very small, very lean servings of red meat may be healthy as part of a primarily plant-based diet like the Mediterranean diet.

The Lies Of The Beef Industry

LiesBoth these studies utilized the very leanest cuts of red meat so they could conclude that red meat is healthy. This is a common design of studies funded by the beef industry. Rather than looking at the health effects of the high fat red meats most people consume, the studies focus only on the leanest cuts of meat.

The studies appear to be designed to purposely mislead the American public. Let’s look at how that happens. When studies like these are incorporated into larger meta-analyses or reviews, investigators often look at the conclusions, not at the experimental design.

Meta-analyses and reviews are only as good as the studies they include, a concept referred to as “Garbage in – Garbage Out”. That is what happened with the review and recommendations I discussed last week. The review relied heavily on short-term randomized controlled trials.

However, this is problematic. Because of the way they are designed, industry funded studies tend to find no adverse effects of consuming red meat. Independently funded studies tend to find adverse health effects from red meat. If you throw them all together without considering how the experiments were designed, the studies cancel each other out.

On that basis the authors of the review concluded that the evidence for red meat adversely affecting health outcomes was weak and recommended that everyone could continue consuming red meat. (That is a recommendation that virtually every health organization and top expert in the field have rejected for the reasons I summarized last week).

The beef industry doesn’t have to influence the design of every study, just enough studies to confuse the science and confuse the media.

The Complicity Of The Media

newspaper heallinesUnfortunately, the media is equally guilty of misleading the public. As I said above, the media is interested in attracting an audience, not in accuracy. For example:

  • The headlines describing the first study should have said: “Saturated fat raises LDL cholesterol levels”. But everyone knows that. Headlines like that are non-controversial. They don’t attract readers.
  • The headlines describing that study could have said: “Very lean cuts of red meat don’t raise LDL levels any more than white meat”. That would have been accurate, but that wouldn’t attract readers either. Most Americans prefer high fat cuts of red meat. They aren’t interested in reading articles suggesting they should change what they are eating.
  • Similarly, the headlines describing the second study should have said: “Very small amounts of very lean red meat may be healthy as part of a Mediterranean diet.”
  • In fact, the authors of both studies admitted in their discussions that they could not extrapolate their findings to the effects of higher-fat red meats. The media ignored those statements. Presumably, they decided the American public didn’t want to hear that message.
  • The first study also found that LDL and related lipoprotein levels were lower for the non-meat protein group than the red and white meat groups at both saturated fat levels. In fact, the main conclusion of the authors was: “The findings are in keeping with recommendations promoting diets with a high proportion of plant foods.” Somehow the media completely ignored that finding.

When the media consistently misleads the public about what constitutes a healthy diet, it leads to confusion. Confusion leads to inaction. At a time when so many Americans are suffering from preventable diseases, this is inexcusable.

Is Red Meat Healthy?

red meat heart healthyLet’s return to the question I posed last week: “Is red meat healthy?” Most of what I say below is identical to what I said last week. However, with the information I provided in the article above it may be easier to understand.

  • The saturated fat in red meat is associated with increased heart disease risk.
  • Red meat increases blood levels of TMAO, which is associated with increased heart disease risk.
  • The heme iron in red meat can be converted in the gut to N-nitroso compounds, which are associated with increased risk of cancer.
  • Benzopyrene and heterocyclic amines are formed when red meat is cooked. And they are associated with increased risk of cancer.

As I said last week, “There are too many studies that show a strong association between red meat consumption and disease risk to give red meat a clean bill of health. We can’t say red meat is healthy with any confidence.”

However, that doesn’t mean we need to eliminate red meat from our diet. As described above, the health risks of red meat are determined by the type of red meat consumed, the amount of red meat consumed, and the overall composition of our diet. For example:

  • Very lean cuts of red meat contain no more saturated fat than white meat.
  • Primarily plant-based diets alter our gut bacteria in such a way that production of TMAO and N-nitroso compounds are decreased.
  • Diets high in plant fiber sweep benzopyrene and heterocyclic amines out of our intestine before they can cause much damage.

So, what does that mean to you?

  • If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat may increase your risk of disease.
  • However, if you are thinking of 2-3 ounces of very lean steak in a vegetable stir fry or a green salad, red meat is probably OK.
  • If you are thinking about the very leanest cuts of red meat, they are probably just as healthy as white meat.

What About Grass Fed Beef?

Of course, one question I am frequently asked is: “What about grass fed beef? Is it healthier than conventionally raised beef?” Grass fed beef does have a slightly healthier fat profile. It is modestly lower in saturated fat and modestly higher in omega-3 fats. However, grass feeding doesn’t affect TMAO, N-Nitroso, benzopyrene, and heterocyclic amine formation.

  • That means the 8-ounce steak is only slightly less unhealthy and the 2-3 ounces of steak in a green salad only slightly healthier when you substitute grass-fed for conventionally raised beef. It’s probably not worth the extra cost.

Next week I will return with the answer to another question I get a lot. “If plant protein is good for me, what about all those meatless burgers that are popping up in my favorite fast food restaurants. Are they healthy?”

The Bottom Line

Last week I wrote about a recent review claiming that the evidence for the health risks of red meat consumption was so weak that the best advice for the American public was to eat as much of it as they like. I pointed out the many flaws in that study.

This week I provided two examples of how the beef industry influences the design of clinical trials to minimize the health risks of red meat and the media misleads the public about what the studies showed.

The bottom line is that red meat likely has no adverse health effects only if you are consuming very small amounts of very lean red meat in the context of a primarily plant-based diet. Unfortunately, this is not the message you are getting from the media and from Dr. Strangelove’s health blog.

As for grass-fed beef, it is only modestly healthier than conventionally raised beef for reasons I have given in the article above. It’s probably not worth the extra cost.

Next week I will return with the answer to another question I get a lot. “If plant protein is good for me, what about all those plant-based burgers that are popping up in my favorite fast food restaurants. Are they healthy?” Stay tuned.

For more details, 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.

 

 

Is Red Meat Healthy For You?

Why Is Red Meat So Controversial?

fatty steakThe American Heart Association, the American Cancer Society, the World Health Organization and other organizations have been telling us for years that diets high in red meat are likely to increase our risk of chronic diseases. If you are like most Americans, you have been trying to cut back on red meat.

However, the latest headlines are saying things like: “Red meat is actually good for you” and “Most adults don’t need to cut back on red meat for their health”. Where did those headlines come from?

A group calling itself the Nutritional Recommendations Consortium (NutriRECS) has reviewed the scientific literature and said: “The evidence is too weak to justify telling individuals to eat less beef and pork.” They have issued guidelines (BC Johnston et al, Annals of Internal Medicine, 171: 756-764, 2019) saying that adults really don’t need to change the amounts of red meat they are eating.

As you can imagine, that has proven to be a controversial recommendation. Many of the top experts in the field have questioned the validity of the study and have condemned the guidelines as misleading.

However, most of you don’t care about arguments between the experts. Your questions are: “What does this study mean to me?” Is everything I have been told about red meat wrong?” “Is red meat healthy after all? Can I really eat as much as I want?”

Why Is Red Meat So Controversial?

ArgumentIf you are confused by the latest headlines, it’s not your fault. Over the past few decades you have been bombarded by conflicting headlines about red meat. One month it is bad for you. The next month it is good for you. It is fair to ask: “Why is red meat so controversial? Why is it so confusing?”

Perhaps the best way to answer those questions is to review the scientific critique of the latest guidelines saying we can eat as much red meat as we want and then look at the authors’ rebuttal.

The best summary of the scientific critique of these guidelines is a WebMD Health News report. Let me cover a few of the most important criticisms:

#1: The NutriRECS group was not backed by any major health, government, or scientific organizations. The members of this group self-nominated themselves as gurus of nutritional recommendations. In an earlier publication they concluded that the evidence was too weak to justify telling individuals to eat less sugar. But in that review they stopped short of recommending that adults could eat as much sugar as they wanted.

#2: The review left out 15 important studies showing that diets high in red meat are associated with increased disease risk. If those studies had been included in the analysis, the link between meat consumption and disease would have been much stronger. Even worse, the omitted studies met the author’s stated criteria for inclusion in their analysis. No reason was given for omitting those studies. This suggests author bias.

#3: The authors used an assessment method that prioritizes evidence from randomized controlled trials and downgrades evidence from association studies. As a result, multiple association studies showing red and processed meat consumption increases disease risk were discounted, and a few randomized controlled clinical trials giving inconsistent results dominated their analysis.

Let me state for the record that my research career was devoted to cancer drug development. I am a big proponent of the value of randomized controlled trials when they are appropriate.

·       Randomized controlled trial are perfect for determining the effectiveness of new drugs. In this context it is appropriate. In a drug trial it is easy to design a randomized, placebo-controlled clinical trial. In addition, every participant already has the disease. If a drug has a benefit, it is apparent in a very short time.

·       However, randomized controlled trials are not optimal for dietary studies. In the first place, it is impossible to design a placebo or have a “blinded study”. People know what they are eating. In addition, diseases like heart disease, cancer, and diabetes take decades to develop. You can’t keep people on specific diets for decades.

·       In addition, because randomized controlled trials are short, they can only measure the effect of diet on disease markers like LDL cholesterol. These disease markers are imperfect predictors of disease outcomes. I will discuss this in more detail next week.

·       Consequently, most of the major studies in nutrition research are “association studies” where the investigators ask people what they customarily eat and look at the association of those dietary practices with disease outcomes. These studies aren’t perfect, but they represent the best tool we have for determining the influence of diet on disease outcomes.

confusion#4: The authors included people’s attitudes about eating meat in their analysis. Because many meat eaters stated they would be unwilling to give up meat, the authors downgraded the association between meat consumption and disease risk.

·       That really had the outside experts scratching their heads. They agreed that people’s attitudes should be considered in discussions about how to implement health guidelines. However, they were unanimously opposed to the idea that people’s opinions should be a factor in crafting health guidelines.

#5: The authors ignored the environmental impact of meat consumption. As I indicated in a previous issue of “Health Tips From the Professor”, this should be a major consideration when choosing your diet.

#6: The authors may have been influenced by the beef industry. The NutriRECS group stated that the Agriculture and Life Sciences (AgriLife) program at Texas A&M provided generous support for their study. While that sound innocuous, the AgriLife program receives financial support from the “Texas Beef Checkoff Program”, which is a meat industry marketing program paid for by cattle ranchers.

#7: The beef industry influenced the studies the authors relied on in their review. The beef industry supports randomized controlled clinical trials on red meat and influences the outcome of those studies in ways that minimize the health effects of red meat consumption. I will give some examples of this next week. Unfortunately, these are the studies the NutriRECS group relied on for their recommendations.

What Did The Authors Say About Their Guidelines?

balance scaleBecause I like to provide a balanced evaluation of nutrition controversies, it is only fair that I summarize the authors argument for their recommendations. However, I will add my commentary. Here is a summary of their arguments.

#1: Nutritional recommendations should be based on sound science. In principle, this is something that everyone agrees on. However, as I noted above randomized controlled trials are not always the best scientific approach for studying the health effects of diet.

My comment: In matters of public health it is better to be safe than sorry. Simply put, it is better to warn people about probable dangers to their health rather than waiting decades for certainty. Smoking is a perfect example. The Surgeon General warned the US public about the dangers of smoking long before the evidence was conclusive.

Smoking is also an example of how industry tries to influence scientific opinion. The tobacco industry supported and influenced research on smoking. Industry funded research tended to minimize the dangers of smoking. Next week I will show how the meat industry is doing the same concerning the dangers of red meat.

#2: It is difficult to get good dietary information in association studies. That is because most association studies ask people what they have eaten over the past few decades. There are two problems with that.

1)    Most people have enough trouble remembering what they ate yesterday. Remembering what they ate 10 or 20 years ago is problematic.

2)    People listen to the news and often change their diets based on what they hear. What they are eating today may not resemble what they ate 10 years ago.

My comment: That is a legitimate point. However, in recent years the best association studies have started collection dietary information at the start, the mid-point, and the end of the study. I agree we need more of those studies.

#3: The authors claim they found no statistically significant link between meat consumption and risk of heart disease, diabetes, or cancer in a dozen randomized controlled trials that had enrolled about 54 000 participants.

label deceptionMy comment: That statement is highly misleading. One of those studies had 48,835 participants. That study wasn’t even designed to measure the effect of red meat consumption. It was designed to measure the health effects of low fat versus high fat diets. The difference in red meat consumption between the two groups was only 1.4 servings per day, a 20% difference. Even with that small difference in red meat consumption, there was about a 2% reduction in some heart disease outcomes, which the authors considered insignificant.

That leaves 11 studies with only 5,165 participants, which averages out to 470 participants per study. Those studies had too few participants to provide any meaningful estimate of the effect of red meat on health outcomes.

In addition, the meat industry influenced the design of some of those studies to further minimize the effect of red meat on health outcomes, something I will discuss next week.

#4: The authors found a slight effect of red meat consumption on heart disease and cancer deaths in association studies, but said the decrease was too small to recommend that people change their diet.

My comment: This represents the folly of looking at any single food or single nutrient rather than the whole diet. We need to take a holistic approach and ask questions like: “What are they replacing red meat with? What does their overall diet look like?

For example, let’s look at what happens when you reduce saturated fats, something I discussed in a previous issue (https://chaneyhealth.com/healthtips/are-saturated-fats-bad-for-you/) of “Health Tips From the Professor”. When you replace saturated fats with:

·       Trans fats, your heart disease risk increases by 5%.

·       Refined carbohydrates and sugars (the kind of carbohydrates in the typical American diet), your heart disease risk increases slightly.

·       Complex carbohydrates (whole grains, fruits and vegetables), your heart disease risk decreases by 9%.

·       Monounsaturated fats (olive oil & peanut oil), your heart disease risk decreases by 15%.

·       Polyunsaturated fats (vegetable oil & fish oil), your heart disease risk decreases by 25%.

·       Unsaturated fats in the context of a primarily plant-based diet like the Mediterranean diet, your heart disease risk decreases by 47%.

While we don’t have such precise numbers for red meat, we do have enough evidence to know that the situation with red meat is similar.

·       Replacing high-fat red meat with low-fat red meat or white meat in the context of a typical American diet will probably have only a modest effect on disease risk.

·       Replacing red meat with plant protein in the context of a typical American diet (think Impossible Burgers or the equivalent at your local Fast Food restaurant) will also probably have only a modest effect on disease risk.

·       Replacing red meat with white meat or plant protein in the context of a primarily plant-based diet is likely to significantly reduce disease risk.

Is Red Meat Healthy For You?

Steak and PotatoesLet’s return to the question I posed at the beginning of this article: “Is red meat healthy for you?” In the context of headlines saying: “Red meat is actually good for you”, the answer is a clear No!

·       The saturated fat in red meat is associated with increased heart disease risk.

·       However, it’s not just saturated fat. Other components of red meat are associated with increased risk of heart disease and cancer. I will discuss those next week.

There are simply too many studies that show an association between red meat consumption and disease risk to give red meat a clean bill of health. We can’t say red meat is healthy with any confidence.

However, that doesn’t mean we need to eliminate red meat from our diet. The health risks of red meat are determined by the type of red meat consumed, the amount of red meat consumed, and the overall composition of our diet. So:Steak Salad

·       If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat is probably not healthy.

·       However, if you are thinking of 2-3 ounces of lean steak in a vegetable stir fry or a green salad, red meat may be healthy.

Of course, one question I am frequently asked is “What about grass fed beef? Is it healthier than conventionally raised beef?” I will answer that question next week.

The Bottom Line

A group calling itself the Nutritional Recommendations Consortium (NutriRECS) recently reviewed the scientific literature and said: “The evidence is too weak to justify telling individuals to eat less beef and pork.” They then issued guidelines saying that adults really don’t need to change the amounts of red meat they are eating.

As you can imagine, that has proven to be a controversial recommendation. Many of the top experts in the field have questioned the validity of the study and have condemned the guidelines as misleading.

When you examine the pros and cons carefully, it becomes clear that the NutriRECS group:

1)    Put too little emphasis on association studies with hundreds of thousands of participants showing a link between red meat consumption and increased risk of heart disease and cancer.

2)    Put too much emphasis on very small randomized controlled trials that had no possibility of evaluating the effect of red meat consumption on disease risk. In part, that is because many of the randomized controlled trials were funded and influenced by the meat industry, something I will discuss next week.

3)    Did not ask what the red meat was replaced with or look at red meat consumption in the context of the overall diet.

Based on what we currently know:

1)    Replacing high-fat red meat with low-fat red meat or white meat in the context of a typical American diet will probably have only a modest effect on disease risk.

2)    Replacing red meat with plant protein in the context of a typical American diet (think Impossible Burgers or the equivalent at your local Fast Food restaurant) will also probably have only a minor effect on disease risk.

3)    Replacing red meat with white meat or plant protein in the context of a primarily plant-based diet is likely to significantly reduce disease risk.

That means:

1)    If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat is probably not healthy.

2)   However, if you are thinking of 2-3 ounces of lean steak in a vegetable stir fry or a green salad, red meat may be healthy.

Of course, one question I am frequently asked is “What about grass fed beef? Is it healthier than conventionally raised beef?” I will answer that question next week. Stay tuned.

For more details, 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.

Is The Paleo Diet Bad For Your Heart?

Is The Paleo Diet Bad For Your Gut?

the paleo dietThere is a lot to like about the Paleo diet:

·       It is a whole food diet. Any diet that eliminates sodas, junk foods, and highly processed foods is an improvement over the American diet.

·       It includes lots of vegetables and some fruits.

·       It helps you lose weight, and any diet that results in weight loss improves your blood work – things like cholesterol, triglycerides, blood sugar control and more.

However, there are concerns the Paleo diet may not be healthy long term.

·       In part, that is because the diet is high in meat, red meat, and saturated fat.

·       Equally important, however, is what the diet eliminates – namely whole grains, legumes (beans), and dairy.

Those of you who have read my book, “Slaying The Food Myths”, know that I say: “We have 5 food groups for a reason”. This is particularly true for the plant food groups. That’s because each plant food group provides a unique blend of:

·       Vitamins and minerals. Those can be replaced with good multivitamin/multimineral supplement.

·       Phytonutrients. You can only get the full complement of health-promoting phytonutrients from a variety of foods from all 5 food groups.

·       Fiber. There are many kinds of fiber and they each play different roles in our intestine. You can only get all the health-promoting varieties of fiber by consuming fruits, vegetables, whole grains and legumes.

·       Gut bacteria. What we call fiber, our gut bacteria call food. Each of the plant food groups supports different populations of friendly gut bacteria.

Based on this reasoning, one might suspect that the Paleo diet might alter our gut bacteria in ways that could be bad for our health. Until recently, this sort of reasoning was just a theoretical concern. That’s because:

1)    We knew far too little about the health effects of different populations of bacteria. This is rapidly changing. Several recent studies have systematically investigated the connection between gut bacteria and health outcomes.

2)    We knew our diet influenced the bacteria populations found in our gut, but we had no understanding of how these changes might influence our health. This too is changing. The study (A Genoni et al, European Journal of Nutrition, https://doi.org/10.1007/s00394-019-02036-y) I discuss this week is an excellent example of recent studies linking diet, gut bacteria, and risk factors for disease.

How Was The Study Done?

can you believe clinical studies doctorThis study recruited 91 participants from Australia and New Zealand. It was a very well designed study in that:

·       The Paleo diet group (44 participants) was recruited based on self-proclaimed adherence to the Paleo diet (< 1 serving/day of grains and dairy products) for one year or more. This is important because short term effects of switching to a new diet are confounded by weight loss and other factors.

o   After analyzing the diets of the Paleo group, the investigators found it necessary to subdivide the group into Strict Paleo (< 1 serving/day of grains and dairy products) and Pseudo-Paleo (> 1 serving/day of grains and dairy).

·       The control group (47 participants) was recruited based on self-proclaimed adherence to a “healthy diet” for 1 year or more with no change in body weight (A healthy diet was defined as a whole food diet containing a variety of foods from all 5 food groups). This is important because far too many studies compare the diet they are promoting to an unhealthy diet with a lot of sugar and highly processed junk foods. These studies provide little useful information because almost anything is better than an unhealthy diet.

·       The participants completed a diet survey based on the frequency of consumption of various foods during the previous year. However, because diet surveys based on the recollection of participants can be inaccurate, the investigators used two rigorous tests to validate the accuracy of those diet surveys.

o   The first was a 3-day weighed dietary record (WDR). Simply put, this means that participants weighed and recorded all foods and beverages before they were eaten for 3 days. Two of those days were weekdays, and one was a weekend day.

o   Secondly, the investigators used blood, urine, and metabolic measures to independently determine protein and energy intake of each participant. Participants who were identified by these means as under reporting both protein and energy were considered unreliable dietary reporters and were excluded from the analysis.

o   It is very rare to find a study that goes to this length to validate the accuracy of the dietary data used in their analysis.

The participants also provided blood, urine and stool samples and completed a physical activity assessment.

What Were The Differences Between The Paleo Diet And The Healthy Control Diet?

Paleo FoodsOnly the Strict Paleo Diet group was faithfully following the Paleo diet. In addition, most of the results with the Pseudo Paleo Diet Group were intermediate between the other two diets. Therefore, to simplify my discussion of this study I will only compare the Strict Paleo Diet group, which I refer to as the Paleo Diet group, with the Healthy Diet control group.

The Paleo diet emphasizes fresh vegetables, especially green leafy vegetables, and discourages grains. Thus, it is no surprise that:

·       The Paleo Diet group ate 74% more vegetables and 3 times more leafy green vegetables than the Healthy Diet group.

·       The Paleo Diet group ate only 3% of the grains and 3% of the whole grains compared to the Healthy Diet group.

The Paleo diet encourages consumption of meat and eggs and discourages consumption of dairy and plant proteins. Thus, it is not surprising that:

·       The Paleo Diet group ate 3 times more red meat and 5 times more eggs than the Healthy Diet group.

·       The Paleo Diet group ate 10% of dairy foods compared to the Healthy Diet group.

·       The Paleo Diet group consumed two times more saturated fat and cholesterol than the Healthy Diet group.

The most interesting comparison between the two diets was the following:

·       Intake of total fiber, insoluble fiber, and soluble fiber was comparable on the two diets.

·       However, intake of resistant starch was 50% lower in the Paleo Diet group. This is significant because:

o   Resistant starch is a type of fiber found primarily in whole grains, legumes, potatoes, and yams (Potatoes and yams are also dietary “no nos” on most low-carb diets).

o   Resistant starch is an especially good food for certain species of healthy gut bacteria.

Is The Paleo Diet Bad For Your Gut?

Bas BacteriaBecause resistant starch affects gut bacteria, the study next looked at the effect of the two diets on the populations of gut bacteria. This is where the story starts to get interesting. When they looked at different groups of gut bacteria, they discovered that:

·       Bifidobacteria were much more abundant in the Healthy Diet group than in the Paleo Diet group, and the amount of Bifidobacteria in the gut was directly proportional to the amount of whole grains in the diet.

o   This is important because previous studies have suggested Bifidobacteria help maintain intestinal barrier integrity and protect against irritable bowel syndrome and obesity.

·       Roseburia were also much more abundant in the Healthy Diet group and proportional to the amount of whole grains in the diet.

o   This is important because previous studies have suggested Roseburia protect against inflammatory bowel diseases like Crohn’s disease and ulcerative colitis.

·       Hungatella were much more abundant in the Paleo Diet group and were inversely proportional to the amount of whole grains in the diet.

o   This is important because Hungatella metabolize carnitine and choline, which are found in meats (especially red meats), egg yolks, and high fat dairy, into a compound called trimethylamine or TMA. TMA is then further metabolized in the liver to trimethylamine-N-oxide, or TMAO.

o   TMAO is a bad player. It is positively associated with heart disease, stroke, kidney disease, diabetes, and Alzheimer’s disease. However, the evidence is strongest for heart disease. TMAO has been called an independent risk factor for cardiovascular death.

Because of this, the study looked at TMAO levels in the blood of the two diet groups. These results were concerning:

·       TMAO levels were 2.5-fold higher in the Paleo Diet group than in the Healthy Diet group.

·       As might be expected, TMAO levels were positively correlated with red meat intake and inversely proportional to whole grain intake.

Is The Paleo Diet Bad For Your Heart?

heart diseaseWhen you put all the evidence together you have a compelling argument that the Paleo diet is likely to increase the risk of heart disease. Let me summarize the data briefly:

1)    The Paleo diet discourages the consumption of whole grains.

2)    Whole grains are a major source of a dietary fiber called resistant starch.

3)    Because the Paleo diet is low in resistant starch, it causes a decrease in two healthy types of gut bacteria and an increase in a type of gut bacteria called Hungatella.

4)    Hungatella metabolize compounds found in meat, eggs, and dairy to a precursor of a chemical called TMAO. This study showed that TMAO levels were 2.4-fold higher in people consuming a Paleo diet.

5)    TMAO is associated with coronary artery disease and is considered an independent risk factor for cardiovascular death.

The authors of the study concluded: “Although the Paleo diet is promoted for improved gut health, results indicate long-term adherence is associated with different gut microbiota and increased TMAO. A variety of fiber components, including whole grain sources, may be required to maintain gut and cardiovascular health.”

Of course, studies like this are looking at associations. They are not definitive. What we need are long term studies looking at the effect of the Paleo diet on heart disease outcomes like heart attack and stroke. Until we have these studies my advice is:

·       Don’t accept claims that the Paleo diet is heart healthy. There are no long-term clinical studies to back up that claim.

·       Be aware that the Paleo diet affects your gut bacteria in ways that may be bad for your heart.

The more we learn about our gut bacteria, the more we appreciate the importance of including all 5 food groups in our diet, especially all the plant food groups.

Are Low Carb Diets Healthy?

low carb dietThe Paleo diet is not the only diet that is high in red meat and low in whole grains. The same is true for virtually all the popular low-carb diets. There are studies showing other low-carb diets also alter gut bacteria and raise TMAO levels, so there is a similar concern that they may also increase the risk of heart disease.

This is in addition to concerns about the high saturated fat consumption which increases the risk of heart disease and red meat consumption, which may increase the risk of certain cancers.

Finally, there are no studies showing that any low-carb diet is healthy long term, even the Atkins diet, which has been around for more than 50 years. Until we have long-term studies about the health consequences of low-carb diets, my advice is similar to that for the Paleo diet.

·       Don’t accept claims that low-carb diets are healthy. There are no long-term clinical studies to back up that claim.

·       Be aware that low-carb diets affect your gut bacteria in ways that may be bad for your health.

The Bottom Line

A recent study looked at the effect of the Paleo diet on an important risk factor for heart disease. Here is a brief summary of the data:

1)    The Paleo diet discourages the consumption of whole grains.

2)    Whole grains are a major source of a dietary fiber called resistant starch.

3)    Because the Paleo diet is low in resistant starch, it causes a decrease in two healthy types of gut bacteria and an increase in a type of gut bacteria called Hungatella.

4)    Hungatella metabolize compounds found in meat, eggs, and dairy to a precursor of a chemical called TMAO. This study showed that TMAO levels were 2.4-fold higher in people consuming a Paleo diet.

5)    TMAO is associated with coronary artery disease and is considered an independent risk factor for cardiovascular death.

Of course, studies like this are looking at associations. They are not definitive. What we need are long term studies looking at the effect of the Paleo diet on heart disease outcomes – like heart attack and stroke. Until we have these studies my advice is:

·       Don’t accept claims that the Paleo diet is heart healthy. There are no long-term clinical studies to back up that claim.

·       Be aware that the Paleo diet affects your gut bacteria in ways that may be bad for your heart.

·       Virtually all the popular low-carb diets discourage consumption of whole grains, so my advice for them is the same as for the Paleo diet.

The more we learn about our gut bacteria, the more we appreciate the importance of including all 5 food groups in our diet, especially all the plant food groups.

For more details on the 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

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