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.

Which Foods Affect Stroke Risk?

Why Is Diet And Stroke Risk So Confusing?

strokeOne day we are told vegetarian diets reduce our stroke risk. The next day we are told they increase stroke risk. It’s the same with red meat, dairy, and eggs. We keep getting mixed messages. It’s enough to make your head spin. Why is diet and stroke risk so confusing?

Part of the problem is that there are two distinct types of stroke. The technical names for them are ischemic stroke and hemorrhagic stroke.

An ischemic stroke occurs when an artery in the brain becomes blocked, shutting off blood flow and damaging part of the brain. This is usually caused by the gradual buildup of fatty deposits and cholesterol plaques in the arteries. When a blood clot forms and lodges in one of the narrowed arteries leading to the brain, an ischemic stroke occurs.

  • Ischemic strokes account for 87% of all strokes.
  • Ischemic strokes are associated with obesity, elevated cholesterol, diabetes, high blood pressure, and smoking.

A hemorrhagic stroke occurs when a weakened blood vessel bursts and bleeds into the surrounding region of the brain. Because our brains are surrounded by a protective skull, that blood has nowhere to go. Pressure from the buildup of blood damages brain cells in the vicinity of the bleed.

  • Hemorrhagic strokes account for only for only 15% of strokes but are responsible for 40% of stroke deaths.
  • The most common cause of a hemorrhagic stroke is the localized enlargement of a blood vessel due to chronic high blood pressure. This weakens the wall of the blood vessel, making it prone to rupturing.

Part of the confusion about diet and stroke risk is because many earlier studies did not distinguish between the two types of stroke.

  • If the studies just measured the incidence of stroke, the data were dominated by ischemic strokes (87% of strokes are ischemic).
  • However, if the studies focused on stroke deaths, hemorrhagic stroke made a larger contribution to the data set (40% of stroke deaths are hemorrhagic).

Fortunately, recent studies have started to focus on the effect of diet on ischemic and hemorrhagic strokes separately. However, many of those studies have been too small to accurately assess the effects of diet on hemorrhagic stroke.

The latest study (TYN Tong et al, European Heart Journal, ehaa007, published February 24, 2020) is one of the largest studies to look at the effect of diet on both kinds of stroke. It has enough patients in the hemorrhagic group to get an accurate estimate of the effect of diet on hemorrhagic stroke.

How Was The Study Done?

Clinical StudyThis study analyzed data on diet and stroke from 418,329 participants in the EPIC (European Prospective Investigation into Cancer and Nutrition). Although the study has cancer in the title, it actually investigated the effect of nutrition on multiple diseases (Presumably, the study title was chosen because EPIC is a more appealing acronym than EPID (European Prospective Investigation into Diseases and Nutrition)).

The participants were recruited from 9 European countries (Denmark, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden, and the UK). The average age of participants was 50, and they were followed for an average of 12.7 years.

At the beginning of the study participants completed country-specific dietary and lifestyle questionnaires.

The dietary assessment was a food frequency questionnaire that asked participants about their dietary intake for the year prior to enrollment in the study. The food frequency data were used to estimate daily intake of red meat, processed meat, poultry, fish, dairy products, eggs, grains, fruits, vegetables, legumes, nuts, seeds, and dietary fiber (It measured total fiber and fiber from grains, fruits and vegetables individually).

The outcome measured was the incidence of ischemic and hemorrhagic strokes during the 12.7-year follow-up.

Which Foods Affect Stroke Risk?

Heart Healthy DietFor ischemic stroke:

  • Each 200 gram/day increase in consumption of fruits and vegetables decreased ischemic stroke risk by 13% (200 grams roughly corresponds to one large apple or one large orange without the skin).
  • Each 10 gram/day increase in consumption of fiber decreased ischemic stroke risk by 23%. Most of this decreased stroke risk was due to fiber from whole grains, fruits, and vegetables.
    • Each 4 gram/day increase in fiber from whole grains decreased ischemic stroke risk by 10%.
    • Each 4 gram/day increase in fiber from fruits and vegetables decreased ischemic stroke risk by 12%.
  • Dairy foods decreased ischemic stroke risk with the following breakdown:
    • Each cup of milk decreased ischemic stroke risk by 5%.
    • Each half cup of yogurt decreased ischemic stroke risk by 9%.
    • Each ounce of cheese decreased ischemic stroke risk by 12%.
  • Each 50 grams/day (2 ounces) of red meat increased ischemic stroke risk by 14%.
    • However, red meat was only half as likely to increase risk of ischemic stroke when the diet was also rich in fruits, vegetables, whole grains, and legumes.

For hemorrhagic stroke:

  • Each 20 gram/day increase in consumption of eggs increased hemorrhagic stroke risk by 25% (20 grams roughly corresponds to about 1/2 of a small egg or 1/3 of a jumbo egg).
  • This study did not measure the effect of salt intake on hemorrhagic stroke risk.

No other foods measured in this study had a significant effect on hemorrhagic stroke risk.

high blood pressureHowever, hemorrhagic stroke is highly associated with high blood pressure. When we look at the influence of foods on high blood pressure, here are the Harvard School of Medicine recommendations for keeping blood pressure low:

  • Eat more fish, nuts and beans in place of high-fat meats.
  • Choose fruits and vegetables instead of sugary, salty snacks and desserts.
  • Select whole grains rather than refined grains.Eat fruit instead of drinking fruit juice.
  • Use unsaturated fats like olive, canola, soybean, peanut, corn or safflower oils instead of butter, coconut oil, or palm-kernel oil.
  • Use herbs, spices, vinegar, and other low-sodium flavorings instead of salt; Choose low-sodium foods whenever possible.

Why Is Diet And Stroke Risk So Confusing?

egg confusionAs I mentioned at the start of this article, part of the reason that the headlines about diet and stroke risk are so confusing is:

  • Many studies did not distinguish between the two types of stroke.
  • Other studies were too small to reliably estimate the effect of food on hemorrhagic stroke risk.

However, there are still some unexplained inconsistencies among recently published studies. It is these inconsistencies I would like to address. For example:

1) In a recent issue of Health Tips From the Professor I reported on a major study (500,000 people followed for 8.9 years) in China. That study came to the opposite conclusion about eggs and risk of hemorrhagic than the EPIC study I discussed above. It found:

  • People consuming one egg per day had a 26% decrease in hemorrhagic stroke risk and a 28% decrease in hemorrhagic stroke deaths compared to people who never or rarely consumed eggs.

In other words, the two studies came to opposite conclusions. In the China study eggs decreased risk of hemorrhagic stroke. In the European study (EPIC) eggs increased risk of hemorrhagic stroke. The reason for this discrepancy is not clear, but one can speculate it might be explained by differences in the underlying diets of the two countries:

  • In China the diet is primarily plant-based. The addition of an egg/day may provide needed protein, fat, and cholesterol (Some cholesterol is essential. We just overdo it in this country).
  • In Europe the diet is already high in protein, saturated fat, and cholesterol. Getting more of them from eggs may not be such a good thing.

In short, if your diet is primarily plant-based, the addition of an egg/day may be a good thing. However, if your diet is already high in meat, saturated fat, and cholesterol, the addition of an egg/day may not be a good thing.

Vegan Foods2) In another recent issue of Health Tips From the Professor I reported on the EPIC-Oxford study that claimed vegetarians had 20% increased risk of hemorrhagic stroke compared to meat eaters.

Interestingly, the EPIC-Oxford study represented a very small portion (~10%) of the overall EPIC study and differed from the rest of the EPIC study in two important ways.

  • It looked at the effect of diets rather than foods on stroke risk.
  • Oxford was the only one of the 22 research centers involved in the EPIC study to invite people following a vegetarian diet to enroll in the study, so it had a much higher proportion of vegetarians than other centers that participated in the study.

The current study did not find any evidence that fruits, vegetables, nuts, seeds, beans, or whole grains influenced the risk of hemorrhagic stroke. In other words, in this much larger data set there was no evidence that the foods associated with a vegetarian diet increased hemorrhagic stroke risk.

However, most of the participants in larger EPIC study were also eating meats. They were not following a pure vegetarian diet.

As I said previously, “If the data on hemorrhagic stroke risk in the EPIC-Oxford study are true, it suggests it may not be a good idea to completely eliminate meat from our diet. However, you don’t need to add much meat to a vegetarian diet. The fish eaters in this study were consuming 1.4 ounces of fish per day. That was enough to eliminate the increased risk of hemorrhagic stroke.”

What Does This Mean For You?

Questioning WomanFor ischemic stroke (blockage of blood flow to the brain), which is the most common form of stroke, the data are clear cut:

  • Fruits, vegetables, whole grains and dairy foods are good for you. (Your mother was right.)
  • Red meat is not so good for you. However, the bad effect of red meat on ischemic stroke risk can be reduced by including plenty of fruits, vegetables, and whole grains in your diet.
  • These conclusions are consistent with multiple previous studies, and the mechanisms of these effects are well established.

For hemorrhagic stroke (bleeding from a weakened blood vessel in the brain) the data are not as clear cut.

  • If you are consuming a primarily plant-based diet, eggs appear to reduce your risk of hemorrhagic stroke.
  • If you are consuming a diet with lots of meat, saturated fat, and cholesterol, adding eggs may increase your risk of hemorrhagic stroke.
  • A vegetarian diet may increase your risk of hemorrhagic stroke. But you don’t need to add much meat to a vegetarian diet. Consuming 1.4 ounces of fish per day appears to be enough to eliminate the increased risk of hemorrhagic stroke.
  • The mechanisms of these effects of food on hemorrhagic stroke are unclear, so these conclusions may be modified by subsequent studies.

In terms of an overall take-home lesson on diet and stroke risk, my advice is: “A primarily plant-based diet is a good idea, but you don’t need to become a vegan purist. Nor do you want to follow fad diets that eliminate whole food groups. We have 5 food groups for a reason. Eliminating any of them may not be a good idea.”

The Bottom Line

A recent study examined the effect of various foods on the risk of the two major forms of stroke.

For ischemic stroke (blockage of blood flow to the brain), which is the most common form of stroke, the data are clear cut:

  • Fruits, vegetables, whole grains and dairy foods are good for you. (Your mother was right.)
  • Red meat is not so good for you. However, the bad effect of red meat on ischemic stroke risk can be reduced by including plenty of fruits, vegetables, and whole grains in your diet.
  • These conclusions are consistent with multiple previous studies, and the mechanisms of these effects are well established.

For hemorrhagic stroke (bleeding from a weakened blood vessel in the brain) the data are not as clear cut.

  • If you are consuming a primarily plant-based diet, eggs appear to reduce your risk of hemorrhagic stroke.
  • If you are consuming a diet with lots of meat, saturated fat, and cholesterol, adding eggs may increase your risk of hemorrhagic stroke.
  • A vegetarian diet may increase your risk of hemorrhagic stroke. But you don’t need to add much meat to a vegetarian diet. Consuming 1.4 ounces of fish per day appears to be enough to eliminate the increased risk of hemorrhagic stroke.
  • The mechanisms of these effects of food on hemorrhagic stroke are unclear, so these conclusions may be modified by subsequent studies.

In terms of an overall take-home lesson on diet and stroke risk, my advice is: “A primarily plant-based diet is a good idea, but you don’t need to become a vegan purist. Nor do you want to follow fad diets that eliminate whole food groups. We have 5 food groups for a reason. Eliminating any of them may not be a good idea.”

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.

 

Are Eggs Bad For You?

Do Eggs Increase Heart Disease Risk?

Author: Dr. Stephen Chaney

 

are eggs bad for youThe “eggfusion” (That’s short for egg confusion) continues.

  • First there were the warnings that eggs were bad for your heart because egg yolks contained cholesterol, and cholesterol was to be avoided at all costs.
  • Then experts decided that dietary cholesterol wasn’t all that bad for you. It was saturated fats, obesity, and lack of exercise that raised “bad” (LDL) cholesterol levels in your bloodstream.
  • That was followed by several US studies suggesting that eggs in moderation (one per day) did not affect your risk of heart disease.
  • Then, about a year ago, a major study claimed that an egg a day actually lowered your risk of heart disease.

Now, the latest headlines claim that eggs increase your risk of heart disease, and you should avoid them. Are eggs bad for you? No wonder you are confused. Let me review the latest study and put it into perspective by comparing it to previous studies.

How Was The Study Done?

are eggs bad for you studyThis study (WW Zhong et al, JAMA, 321: djw322, 2017 combined the data from 6 clinical trials in the United States that assessed dietary intake and measured cardiovascular health outcomes. In all, these studies included 29,615 adults who were followed for an average of 17.5 years.

The diet of the participants was assessed upon entry into each of the clinical trials. The primary variables derived from the dietary information were cholesterol and egg consumption. Diet was not assessed at later times in these studies.

The primary outcomes measured were heart disease and all-cause mortality. In this study heart disease was an umbrella term that included fatal and non-fatal heart attacks, stroke, heart failure, and death from other heart-related causes.

The association of cholesterol and eggs with heart disease and mortality were similar. Similarly, the effect of cholesterol and eggs on both heart disease risk and mortality were similar. Most people know how many eggs they eat but have no idea how much cholesterol they consume. Thus, for simplicity I will just focus on the association between egg consumption and heart disease risk.

 

Do Eggs Increase Heart Disease Risk?

do eggs increase heart attacksHere are the main findings from this study.

  • Each additional half an egg consumed per day (which is equivalent to 3-4 eggs per week) was associated with a:
  • 6% increased risk of heart disease. While that doesn’t sound like much, the increased risk was over 13% for one egg per day and almost 27% for two eggs per day.
  • The increased heart disease risk associated with one half egg per day was greater for:
  • Women (13% increase) than men (3% increase)
  • People who already had high blood cholesterol (7% increase) than people who already had low cholesterol levels (0% increase). This suggests that the effect of eggs on heart disease risk primarily affects people who are already having trouble controlling their blood cholesterol levels – either due to genetics or due to diet & lifestyle.

Of course, the question is whether it was the eggs that increased the risk of heart disease or was it something else in the diet. This study attempted to answer that question by systematically subtracting out other variables that affect heart disease risk to see whether that correction eliminated the association between egg consumption and heart disease risk. When this was done:

  • The association between egg consumption and heart disease risk disappeared after correcting for dietary cholesterol intake.
  • The association between egg consumption and heart disease risk remained significant after correcting for other components of the diet, such as fats, animal protein, fiber, sodium, or overall “diet quality”. There were 3 main measures of diet quality.
  • The Med diet score measures how closely the diet resembles the Mediterranean diet.
  • The DASH diet score measures how closely the diet resembles the DASH diet.
  • The Healthy Eating Index (HEI) measures how closely the diet aligns with the USDA Dietary Guidelines For Americans. Basically, the HEI recommends a whole food diet containing foods from all 5 food groups with a heavy emphasis on fruits, vegetables, whole grains, and legumes. It also recommends limiting saturated and trans fats, added sugars, and sodium.

In simple terms these data suggest that the effect of eggs on heart disease risk was primarily due to their cholesterol content and was not influenced by other components of the overall diet.

What Are The Strengths And Weaknesses Of The Study?

are eggs bad for you strength weakness studyThe strengths are obvious. This was a very large study (29,615 participants) and the people enrolled in the study were followed for a long time (an average of 17.5 years). The primary variables in the study (cholesterol consumption, egg consumption, heart disease, and all-cause mortality) were accurately measured in each of the clinical trials included in the study.

However, there were some significant weaknesses as well:

  • Cholesterol and egg consumption were only measured by a single dietary survey when people entered the study. This study assumes they did not change over the course of the study. That is very unlikely. Both cholesterol intake and egg consumption in the US population have waxed and waned over the years, in part due to variations in dietary guidelines.
  • The measurements of diet quality used were based on US and European food preferences. That is significant because the only studies showing that egg consumption lowers heart disease risk were performed in China and Japan, where the diet is closer to semi-vegetarian than to US or European diets.

 

Are Eggs Bad For You?

thumbs downAre eggs bad for you?

This is very large, well designed study that combines the data from 6 clinical trials spanning the years 1974 to 2013.

The strongest conclusions from the study are:

  • In the context of a Western diet (the US diet) egg consumption slightly increases your risk developing heart disease. The increased risk is ~6% for 3-4 eggs/week, ~13% for 1 egg per day, and ~27% for two eggs per day.
  • The increased risk of heart disease appears to be almost entirely due to the cholesterol content of eggs.

The significance of this study needs to be weighed in the context of:

  • Recent studies in the US and Europe showing eggs do not increase heart disease risk.
  • Studies in China and Japan (where the diets can best be described as semi-vegetarian) showing that eggs decrease heart disease risk.

The significance of this study also needs to be weighed in the context of:

  • Studies showing that obesity, saturated fat, and physical inactivity have bigger effects on serum cholesterol levels and heart disease risk than dietary cholesterol from foods like eggs.

What Did This Study Miss?

are eggs bad for you breakfastIf, as this study suggests, the effect of eggs on heart disease risk is due to their cholesterol content, this study (and most previous studies) missed a very important point. The effect of dietary cholesterol on blood cholesterol levels is not strongly affected by the overall composition of the diet. It is affected by the composition of the diet at the time foods containing dietary cholesterol are eaten.

  • The kind of fiber found in certain fruits, vegetables, whole grains, and legumes bind to dietary cholesterol, preventing it from being absorbed as it passes through the intestine.
  • Certain phytonutrients in plant foods affect how dietary cholesterol is utilized by the body.
  • Our gut bacteria depend on the fiber we eat. They utilize the fiber for energy and release metabolites that affect how dietary cholesterol is utilized by the body.
  • However, to blunt the effect of dietary cholesterol on blood cholesterol levels, the fiber and phytonutrient-containing foods must be consumed at the same meal.

Simply put, if your breakfast consists of eggs, sausage, biscuits, and hash browns, the cholesterol in the eggs will likely increase your blood cholesterol level, which in turn increases your risk of heart disease. This will occur even if you eat lots of fruits, vegetables, whole grains, and legumes with your other meals.

If, on the other hand, your breakfast consists of eggs and fiber-rich plant foods like oatmeal and beans, the cholesterol in the eggs will likely have a much smaller effect on your blood cholesterol levels and your heart disease risk.

The fact that previous studies have not looked at what foods were consumed along with the eggs may explain some of the variation in their conclusions about the effect of egg consumption on heart disease risk.

 

The Professor’s Story

professor owlLet me share my story with you. About 25 years ago, my doctor told me that my cholesterol levels were getting high and wanted to put me on statins. I didn’t stop eating eggs for breakfast. I changed breakfast.

Now I soft boil my eggs or fry them in olive oil. I eat them along with oatmeal, which contains a fiber that binds cholesterol, and walnuts, which contain omega-3s and phytonutrients that lower blood cholesterol. I also include whatever fruit is in season. Finally, I take a supplement providing 2 grams of plant stanols and sterols, which block cholesterol absorption from the intestine.

My blood cholesterol levels have been low ever since. I have not had to take statins, and I get to enjoy the taste and health benefits of an egg every day. Of course, what worked for me may not work for you. The effect of dietary cholesterol on blood cholesterol levels is also affected by genetics, weight, and fitness, just to name the top three.

 

Are Eggs Bad For You or Good For You?

thumbs upOnce you get past the cholesterol problem, eggs are a very healthy food.

  • Studies have shown that egg protein results in better blood sugar control, better satiety (feeling of fullness), and reduced subsequent food intake in healthy and overweight individuals. In layman’s terms that means egg protein can help you achieve and maintain a healthy weight.
  • Egg yolks are a good source of lutein and zeaxanthin. We think of lutein and zeaxanthin as good for eye health. They also play an important role in protecting against oxidation, inflammation, and atherosclerosis.
  • Egg yolks also contain choline. We think of choline as good for brain and nerves. But, choline and other phospholipids in the yolk also raise HDL levels and enhance HDL function.
  • Eggs are a good source of vitamin A, vitamin D, vitamin B12, riboflavin, selenium and iron.
  • Eggs contain almost twice as much monounsaturated and polyunsaturated fats as saturated fats.

What Does This Mean For You?

  • what does this mean for youThe latest study suggests that eggs may increase your risk of heart disease, and this is due to their cholesterol content.
  • This study needs to be considered in the context of recent studies in the US showing that egg consumption did not increase heart disease risk and studies in China and Japan showing that egg consumption lowered heart disease risk.
  • It is also important to consider that egg consumption in China and Japan is in the context of a semi-vegetarian diet. This suggests that diet plays a role in determining the effect of egg consumption on heart disease risk.
  • However, if you take this study at face value, there are two things you can do to reduce your risk of heart disease:
  • Reduce dietary cholesterol by avoiding eggs or using egg whites.
  • Eat eggs in moderation along with fiber- and phytonutrient-rich plant foods that negate the effect of dietary cholesterol on blood cholesterol levels. I recommend oatmeal or beans, nuts or seeds, and fiber rich fruits and vegetables. These should be consumed at the same meal to minimize the effect of the cholesterol in the eggs on blood cholesterol levels.
  • Eggs are a very healthy food, so I recommend the second option if possible. Get your blood cholesterol levels measured to determine which approach works best for you.
  • Finally, we need to recognize that egg consumption plays a relatively minor role in determining heart disease risk. Other factors play a much larger role in influencing heart disease risk. For example:
  • Smoking, obesity, inactivity, saturated and trans fats significantly increase your risk of heart disease.
  • Omega-3s, antioxidants, and a primarily plant-based diet like the Mediterranean diet significantly decrease your risk of heart disease.

If we wish to reduce our risk of heart disease, this is where we should focus most of our attention. We can minimize the effect of egg consumption on heart disease risk by changing the foods we eat with the eggs. For more information on how to reduce your risk of heart disease, read my books, “Slaying The Food Myths” and “Slaying The Supplement Myths.”

 

The Bottom Line

  • The latest study suggests that eggs increase your risk of heart disease because of their cholesterol content.
  • This was a very large study. It combined the data from 6 clinical trials spanning the years 1974 to 2013. It followed 29,615 people for an average of 17.5 years. However, it has two significant weaknesses:
  • It only determined cholesterol intake and egg consumption at the time people entered the clinical trials. Both cholesterol intake and egg consumption have waxed and waned considerably over the years covered by these clinical trials.
  • It did not measure what foods were consumed along with the eggs. Foods consumed along with eggs have a strong influence on how much the cholesterol in the eggs influences blood cholesterol levels, which, in turn, influences the effect eggs have on heart disease risk.
  • This study also needs to be considered in the context of recent studies in the US showing that egg consumption did not increase heart disease risk and studies in China and Japan showing that egg consumption lowered heart disease risk.
  • However, if you take this study at face value, there are two things you can do to reduce your risk of heart disease:
  • Reduce dietary cholesterol by avoiding eggs or using egg whites.
  • Eat eggs in moderation along with fiber- and phytonutrient-rich plant foods that negate the effect of dietary cholesterol on blood cholesterol levels. I recommend oatmeal or beans, nuts or seeds, and fiber rich fruits and vegetables. These should be consumed at the same meal to minimize the effect of the cholesterol in the eggs on blood cholesterol levels.
  • Eggs are a very healthy food, so I recommend the second option if possible. Get your blood cholesterol levels measured to determine which approach works best for you.
  • Finally, we need to recognize that egg consumption plays a relatively minor role in determining heart disease risk. Other factors play a much larger role in influencing heart disease risk. For example:
  • Smoking, obesity, inactivity, saturated and trans fats significantly increase your risk of heart disease.
  • Omega-3s, antioxidants, and a primarily plant-based diet like the Mediterranean diet significantly decrease your risk of heart disease.

If we wish to reduce our risk of heart disease, these are the areas where we should focus most of our attention. We can minimize the effect of egg consumption on heart disease risk by changing the foods we eat with the eggs. For more information on how to reduce your risk of heart disease, read my books, “Slaying The Food Myths” and “Slaying The Supplement Myths.”

For more details and to learn how the professor does about egg consumption, read the article above.

 

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

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