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.

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.

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.

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.

Are Saturated Fats Good For You?

Is Everything We Thought We Knew About Fats Wrong?

Author: Dr. Stephen Chaney

fatty steakBring out the fatted calf! Headlines are proclaiming that saturated fats don’t increase your risk of heart disease – and that they may actually be good for you.

The study (Annals of Internal Medicine, 160: 398-406, 2014) that attracted all the attention in the press was what we scientists call a meta-analysis. Basically, that is a study that combines the data from many clinical trials to improve the statistical power of the effect being studied.

And it was a very large study. It included 81 clinical trials that looked at the effects of various types of fat on heart disease risk.

Are Saturated Fats Good For You?

The answer to this question is a simple No. The headlines suggesting that saturated fats might be good for you were clearly misleading. The study concluded that saturated fats might not increase the risk of heart disease, but it never said that saturated fats were good for you.

In short, the study concluded that:

  • Saturated fats, monounsaturated fats and long-chain omega-6 polyunsaturated fats did not affect heart disease risk.
  • Long chain omega-3 polyunsaturated fats decreased heart disease risk [Note: The original version of the paper said that the decrease was non-significant, which is what the headlines have reported. However, after several experts pointed out an error in their analysis of the omega-3 data, the authors corrected their analysis, and the corrected data show that the decrease in risk is significant.]
  • Trans fats increased heart disease risk

If those conclusions are correct, they would represent a major paradigm shift. We have been told for years that we should limit saturated fats and replace them with unsaturated fats. Has that advice been wrong?

Is Everything We Thought We Knew About Fats Wrong?

Before we bring out the fatted calf and start heaping butter on our12 ounce steaks, perhaps we should look at some of the limitations of this study.

We Eat Foods, Not Fats

When the authors broke the data down into the effects of individual saturated and unsaturated fatty acids on heart disease risk some interesting insights emerge.

For example, with respect to saturated fats:

  • Both palmitic acid and stearic acid – which are abundant in palm oil and animal fats – increased the risk of heart disease.
  • On the other hand, margic acid – which is more abundant in dairy products – decreased the risk of heart disease.

Whipped CreamSo while the net effect of saturated fats on heart disease risk may be zero, these data suggest:

  • It is still a good idea to avoid fatty meats, especially red meats, if you want to reduce your risk of heart disease. When you focus on foods, rather than fats this fundamental advice has not changed in over 40 years! In next week’s “Health Tips From the Professor” I will share some of the latest research on the dangers of red meat.
  • With fatty dairy foods the situation is a little more uncertain. I’m not ready to tell you to break out the butter and whipped cream just yet, but recent research does suggest that dairy foods have some beneficial effects that may outweigh their saturated fat content.

With respect to omega-3 fatty acids:

  • alpha-linolenic acid – which is found in vegetable oils and nuts and is the most abundant omega-3 fatty acids in our diets – had no effect on heart disease risk.
  • On the other hand, EPA and DHA – which are found primarily in oily fish and omega-3 supplements – decreased heart disease risk by 20-25%.

Once again, while the net effect of omega-3 fatty acids on heart disease risk was very small, that’s primarily because most Americans consume mostly alpha-linolenic acid and very little EPA and DHA. This study shows that fish oil significantly reduces heart disease risk, which is fully consistent with the heart healthy advice of the American Heart Association and National Institutes of Health over the past decade or more.

What We Replace the Fats With Is Important

A major weakness of the current study is that it did not ask what the individual clinical trials were replacing the fatty acids with. Many of them were simply replacing the saturated fats with carbohydrates. To understand why that is important, you have to go back to the research of Dr. Ancel Keys.

The whole concept of saturated fats increasing the risk of heart disease is based on the groundbreaking research of Dr. Ancel Keys in the 50’s and 60’s. But, it is important to understand what his research showed and didn’t show.

His research showed that when you replaced saturated fats with monounsaturated fats and/or polyunsaturated fats the risk of heart disease was significantly reduced. He was the very first advocate of what we now call the Mediterranean diet. (He lived to 101 and his wife lived to 97, so he must have been on to something.)

Unfortunately, his diet advice got corrupted. The mantra became low fat diets, where the saturated fat was replaced with carbohydrates – mostly simple sugars and refined flours. Since diets containing a lot of simple sugars and refined flours also increase the risk of heart disease you completely offset the benefits of getting rid of the saturated fats.

Just in case you think that is outdated dietary advice, Dr. Key’s recommendations were confirmed by a major meta-analysis published in 2009 (American Journal of Clinical Nutrition, 89: 1425-1432, 2009). That study showed once again that replacing saturated fats with carbohydrates had no effect on heart disease risk, while replacing them with polyunsaturated fats significantly reduced risk.

The Bottom Line:

You can put the fatted calf back out to pasture. The headlines telling you that saturated fats don’t increase the risk of heart disease were overstated and misleading. This study does not represent a paradigm shift. In fact, when you analyze the study in depth it simply reaffirms much of the current dietary advice about fats.

1)     When you simply replace saturated fats with carbohydrates, as did many of the studies in the meta-analysis that generated all of the headlines, there is little or no effect on heart disease risk. However, other studies have shown that when you replace the saturated fats with monounsaturated and polyunsaturated fats you significantly reduce heart disease risk.

In short, if you are interested in reducing your risk of heart disease, low fat diets may be of relatively little value while Mediterranean diets may be beneficial. No paradigm shift there. That sounds pretty familiar.

2)     Fatty meats, especially red meats, appear to increase the risk of heart disease. No surprises there.

3)     Alpha-linolenic acid, the short chain omega-3 fatty acid found in nuts, seeds and vegetable oils, does not decrease heart disease risk. However, EPA and DHA, the long chain omega-3 fatty acids found in fatty fish and fish oil supplements significantly decrease heart disease risk. That’s probably because the efficiency of conversion of alpha-linolenic acid to EPA & DHA in our bodies is only around 10%. No surprises there.

4)     The study did suggest that dairy foods may decrease heart disease risk. While there are a few other studies supporting that idea, I’m not ready to break out the butter and whipped cream yet. More research is needed.

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.

Do NOT follow this link or you will be banned from the site!