Protein and Heart Disease: Meat vs Plant-Based

Written by Dr. Steve Chaney on . Posted in Protein and Heart Disease

Does Meat Protein Increase Heart Disease Risk?

Author: Dr. Stephen Chaney

 

Is a plant-based diet better than eating meat when it comes to protein and heart disease?

protein and heart disease plant-basedThere are a multitude of studies showing the long-term health benefits of plant-based diets. Among the best of these studies are the Seventh-Day Adventist Studies. That’s because the Adventist church advocates a vegan diet but allows personal choice. This means Seventh-Day Adventists eat a more plant-based diet than most Americans. However, there is also significant variation in the diet of Adventists.

 

Not all Adventists are vegans. Significant numbers of Adventists choose lacto-ovo-vegetarian (dairy, eggs & vegetarian), pesco-vegetarian (fish & vegetarian), and semi-vegetarian (meat & vegetarian).

Because of this variation, Adventists provide a rich database for clinical studies. You can compare health outcomes of a vegetarian diet to the standard American diet by comparing Adventists to the non-Adventist population living in the same area. You can also use the Adventist population to compare the health outcomes of the various types of vegetarian diets.

I have described the Adventist Health Studies in detail in my new book, Slaying The Food Myths. Let me briefly summarize the results with an emphasis on heart disease risk:

  • Compared to the standard American Diet, vegetarian diets decrease cardiovascular deaths by 41% in men and 51% in women.
  • The reduction in cardiovascular death is greater for vegans than for lacto-ovo-vegetarians.
  • If we look at the average of multiple studies, the risk of heart disease, diabetes, and cancer is less for vegans than for lacto-ovo-vegetarians, which is less than the risk for pesco-vegetarians, which is less than the risk for semi-vegetarians, which is much less than the risk for people consuming the standard American diet.

There are multiple reasons why vegetarian diets decrease the risk of heart disease compared to the standard American diet. These will be discussed below. The current study was designed to look at the proteins found in vegetarian and non-vegetarian diets and ask what effect these proteins had on heart disease.  This was a good study of protein and heart disease.

How Was The Study Done?

protein and heart disease heart healthThis study (M. Tharrey et al, International Journal of Epidemiology, 2018, 1-10 doi: 10.1093/ije/dyy030 ) utilized a database of 81,337 men and women over age 25 who were enrolled in the Adventist Health Study-2 between 2002 and 2007.

At the time of enrollment, a very detailed food frequency questionnaire was administered. The participants were divided into groups based on the most prevalent protein source in their diet as follows:

  • Grains: This group averaged 44% of their protein intake from grains.
  • Processed foods: This category included protein from cheese, eggs, and milk. However, it also included processed plant proteins and protein from cold breakfast cereals.
  • Meats: The largest protein contributors to this category were red meat, processed meat, and poultry. Fish made only a minor contribution.
  • LFV (Legumes, fruits & vegetables): Legumes were the biggest protein contributors in this category.
  • Nuts and seeds: This included peanuts, tree nuts and seeds.

The participants in the study were followed for an average of 9.4 years during which there were 2276 cardiovascular deaths. The study then asked what effect protein intake from each of these food groups had on cardiovascular risk.

 

Meat Protein and Heart Disease?

 

protein and heart disease meatsSome of the findings from this study were expected, but some were surprising. When studying protein and heart disease for example:

  • When they compared people getting the most protein from meat with those getting the least (24% versus 1% of their protein intake from meat), the risk of cardiovascular death was increased by 61%. This is consistent with several previous studies suggesting that meat, particularly red meat, increases the risk of heart disease.
  • When they compared people getting the most protein from nuts and seeds with those getting the least (18% versus 2%), the risk of cardiovascular death was decreased by 40%. Again, this is consistent with previous studies suggesting that nuts and seeds reduce the risk of heart disease.
  • They found no significant effect of protein intake from grains on cardiovascular death. This could be considered as surprising because whole grains are an excellent source of fiber, which reduces the risk of heart disease. However, the difference in protein intake between the groups getting the most protein from grains versus the least was relatively small (34% versus 19%). In addition, the study did not differentiate between whole grains and refined grains.
  • There was a slight, but non-significant, increased risk of cardiovascular death for people getting the highest amount of protein from processed foods. This is also a bit surprising. It may be because the survey included both meat-based and vegetarian processed foods in the processed foods classification, and there are many processed foods that are marketed specifically to vegetarians.
  • There was also no significant effect of protein from legumes, fruits and vegetables on cardiovascular death. This is also surprising and will be discussed below.

The authors concluded “Our results suggest that healthy choices can be advocated based on protein sources, specifically preferring diets low in meat intake and with a higher intake of plant proteins from nuts and seeds.”

What Does This Mean For You?

protein and heart disease nuts and seedsThis study does not fundamentally alter what we know about diet and heart disease risk. That is because this study focused solely on the protein and heart disease not on the foods and heart disease. The data were statistically corrected for every other beneficial and detrimental effect of those foods. For example:

  • The people in this study with the highest intake of processed foods were more likely to be overweight and physically inactive. They were also more likely to be smokers. These factors increase the risk of cardiovascular disease. However, the data were statistically adjusted to remove these considerations from the analysis.
  • The people in this study with the highest intake of whole grains, legumes, fruits and vegetables also had the highest intake of fiber, antioxidants, and B vitamins. These factors decrease the risk of heart disease. However, the data were statistically adjusted to remove these considerations from the analysis.

In short, processed foods are still probably bad for the heart, but that is not due to the protein component of processed foods. Similarly, whole grains, legumes, fruits, and vegetables are still good for the heart, but it is not the protein component of these foods that conveys the heart-healthy benefits.

Where the study breaks new ground and leaves some unanswered questions is with the effect of meat, nuts, and seeds on heart disease risk. For example:

  • The American Heart Association has recently released a Presidential Advisory statement warning that the saturated fat in meats increases heart disease risk. However, the data in the present study were statistically adjusted to remove the effect of saturated fat from the analysis. Thus, this study suggests that the protein in red meat also contributes to heart disease risk. If this is confirmed by subsequent studies, it is an important advance. It might mean, for example, that grass-fed beef is no healthier than conventionally raised beef.

However, it is unclear why meat protein increases heart disease risk. One recent study has suggested that meat-based diets favor a population of gut bacteria that metabolize a compound called carnitine, also found in meat, into a metabolite that increases heart disease risk. However, this mechanism has not yet been confirmed.

[Note: The effects of saturated fats and carnitine on heart disease risk are covered in detail in my new book “Slaying the Food Myths.” In my book I carefully analyze the arguments of saturated fat proponents as well as saturated fat opponents.]

  • Conventional wisdom has attributed the heart health benefits of nuts and seeds to their omega-3 fatty acids. However, the data in this study were statistically adjusted to remove the effect of omega-3 fatty acids from the analysis. Thus, this study suggests that the protein in nuts and seeds decreases heart disease risk.

Once again, the mechanism of this effect is unclear. The authors suggest it might be due to higher levels of the amino acids glutamate and arginine in seed and nut protein. However, these two amino acids are abundant in a variety of plant-based proteins. Their presence in nut and seed proteins would not appear to be sufficient to confer a special heart health benefit.

In short, this is the first study of this kind and the mechanisms of the effects described are unclear. Thus, one cannot yet definitively claim that meat protein is bad for the heart and nut and seed proteins are good for the heart.

Whether it is the protein component of these foods that affects heart health is relatively unimportant. It does not change what we know about diet and heart health. As discussed in “Slaying The Food Myths,” multiple studies show that meat-based diets increase heart disease risk and primarily plant-based diets decrease heart disease risk. Multiple studies also show that nuts and seeds decrease heart disease risk.

 

The Bottom Line:

 

A recent study looked at the effect of the protein content of various foods on heart disease risk. The study reported:

  • Meat protein increased the risk of cardiovascular deaths by 61%.
  • Proteins from nuts and seeds decreased the risk of heart disease deaths by 40%.
  • Proteins from processed foods, grains, legumes, fruits, and vegetables had no effect on cardiovascular deaths.

This study does not fundamentally alter what we know about diet and heart disease risk. That is because this study focused solely on the protein component of various foods rather than the foods themselves. The data were statistically corrected for every other beneficial and detrimental effect of those foods. Because of that:

  • Processed foods are still probably bad for the heart
  • Whole grains, legumes, fruits and vegetables are still good for the heart.
  • Meat, especially red meat, is probably bad for the heart, while nuts and seeds are good for the heart.

The major new information provided by this study is that:

  • The increased risk of heart disease associated with meats is not just due to their saturated fat content. Meat protein may also increase heart disease risk. If confirmed by subsequent studies, this is an important finding because it suggests that lean cuts of meat and grass-fed beef may not eliminate heart disease risk.
  • The decreased risk of heart disease associated with nuts and seeds is not just due to their omega-3 content. Nut and seed proteins may also decrease heart disease risk.

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.

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Comments (2)

  • Ruth Uhl

    |

    Question – does it appear that there is any difference if one is eating more wild-caught fish and organic chicken, as opposed to red meat?

    Reply

    • Dr. Steve Chaney

      |

      Dear Ruth,
      That is definitely a step in the right direction, especially the wild-caught fish. The other thing to consider is proportions. A small amount of meat in a primarily plant-based diet is likely to be healthier than a small amount of fruits, vegetables, and whole grains in a primarily meat-based diet.
      Dr. Chaney

      Reply

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Latest Article

Does Magnesium Optimize Vitamin D Levels?

Posted February 12, 2019 by Dr. Steve Chaney

The Case For Holistic Supplementation

Author: Dr. Stephen Chaney

 

Does magnesium optimize vitamin D levels?

magnesium optimize vitamin dOne of the great mysteries about vitamin D is the lack of correlation between vitamin D intake and blood levels of its active metabolite, 25-hydroxyvitamin D. Many people who consume RDA levels of vitamin D from foods and/or supplements end up with low blood levels of 25-hydroxyvitamin D. The reason(s) for this discrepancy between intake of vitamin D and blood levels of its active metabolite are not currently understood.

Another great mystery is why it has been so difficult to demonstrate benefits of vitamin D supplementation. Association studies show a strong correlation between optimal 25-hydroxyvitamin D levels and reduced risk of heart disease, cancer, and other diseases. However, placebo-controlled clinical trials of vitamin D supplementation have often come up empty. Until recently, many of those studies did not measure 25-hydroxyvitamin D levels. Could it be that optimal levels of 25-hydroxyvitamin D were not achieved?

The authors of the current study hypothesized that optimal magnesium status might be required for vitamin D conversion to its active form. You are probably wondering why magnesium would influence vitamin D metabolism. I had the same question.

The authors pointed out that:

  • Magnesium status affects the activities of enzymes involved in both the synthesis and degradation of 25-hydroxyvitamin D.
  • Some clinical studies have suggested that magnesium intake interacts with vitamin D intake in affecting health outcomes.
  • If the author’s hypothesis is correct, it is a concern because magnesium deficiency is prevalent in this country. In their “Fact Sheet For Health Professionals,” the NIH states that “…a majority of Americans of all ages ingest less magnesium from food than their respective EARs [Estimated Average Requirement]; adult men aged 71 years and older and adolescent females are most likely to have low intakes.” Other sources have indicated that magnesium deficiency may approach 70-80% for adults over 70.

If the author’s hypothesis that magnesium is required for vitamin D activation is correct and most Americans are deficient in magnesium, this raises some troubling questions.

  • Most vitamin D supplements do not contain magnesium. If people aren’t getting supplemental magnesium from another source, they may not be optimally utilizing the vitamin D in the supplements.
  • Most clinical studies involving vitamin D do not also include magnesium. If most of the study participants are deficient in magnesium, it might explain why it has been so difficult to show benefits from vitamin D supplementation.

Thus the authors devised a study (Q Dai et al, American Journal of Clinical Nutrition, 108: 1249-1258, 2018 ) to directly test their hypothesis.

 

How Was The Study Designed?

magnesium optimize vitamin d studyThe authors recruited 180 volunteers, aged 40-85, from an ongoing study on the prevention of colon cancer being conducted at Vanderbilt University. The duration of the study was 12 weeks. Blood was drawn at the beginning of the study to measure baseline 25-hydroxyvitamin D levels. Three additional blood draws to determine 25-hydroxyvitamin D levels were performed at weeks 1, 6, and 12.

Because high blood calcium levels increase excretion of magnesium, the authors individualized magnesium intake based on “optimizing” the calcium to magnesium ratio in the diet rather than giving everyone the same amount of magnesium. The dietary calcium to magnesium ratio for most Americans is 2.6 to 1 or higher. Based on their previous work, they considered an “ideal” calcium to magnesium ratio to be 2.3 to 1. The mean daily dose of magnesium supplementation in this study was 205 mg, with a range from 77 to 390 mg to achieve the “ideal” calcium to magnesium ratio. The placebo was an identical gel capsule containing microcrystalline cellulose.

Two 24-hour dietary recalls were conducted at baseline to determine baseline dietary intake of calcium and magnesium. Four additional 24-hour dietary recalls were performed during the 12-week study to assure that calcium intake was unchanged and the calcium to magnesium ratio of 2.3 to 1 was achieved.

In short this was a small study, but it was very well designed to test the author’s hypothesis.

 

Does Magnesium Optimize Vitamin D Levels?

 

does magnesium optimize vitamin d levelsThis was a very complex study, so I am simplifying it for this discussion. For full details, I refer you to the journal article (Q Dai et al, American Journal of Clinical Nutrition, 108: 1249-1258, 2018).

The most significant finding was that magnesium supplementation did affect blood levels of 25-hydroxyvitamin D. However, the effect of magnesium supplementation varied depending on the baseline 25-hydroxyvitamin D level at the beginning of the study.

  • When the baseline 25-hydroxyvitamin D was 20 ng/ml or less (which the NIH considers inadequate), magnesium supplementation had no effect on 25-hydroxyvitamin D levels.
  • When the baseline 25-hydroxyvitamin D was 20-30 ng/ml (which the NIH considers the lower end of the adequate range), magnesium supplementation increased 25-hydroxyvitamin D levels.
  • When the baseline 25-hydroxyvitamin D level approached 50 ng/ml (which the NIH says may be “associated with adverse effects”), magnesium supplementation lowered 25-hydroxyvitamin D levels.

The simplest interpretation of these results is:

  • When vitamin D intake is inadequate, magnesium cannot magically create 25-hydroxyvitamin D from thin air.
  • When vitamin D intake is adequate, magnesium can enhance the conversion of vitamin D to 25-hydroxyvitamin D.
  • When vitamin D intake is too high, magnesium can help protect you by lowering 25-hydroxyvitamin D levels.

The authors concluded: “Our findings suggest that optimal magnesium status may be important for optimizing 25-hydroxyvitamin D status. Further dosing studies are warranted…”

 

What Does This Study Mean For You?

magnesium optimize vitamin d for youThis was a groundbreaking study that has provided novel and interesting results.

  • It provides the first evidence that optimal magnesium status may be required for optimizing the conversion of vitamin D to 25-hydroxyvitamin D.
  • It suggests that optimal magnesium status can help normalize 25-hydroxyvitamin D levels by increasing low levels and decreasing high levels.

However, this was a small study and, like any groundbreaking study, has significant limitations. For a complete discussion of the limitations and strengths of this study I refer you to the editorial (S Lin and Q Liu, American Journal of Clinical Nutrition, 108: 1159-1161, 2018) that accompanied the study.

In summary, this study needs to be replicated by larger clinical studies with a more diverse study population. In order to provide meaningful results, those studies would need to carefully control and monitor calcium, magnesium, and vitamin D intake. There is also a need for mechanistic studies to better understand how magnesium can both increase low 25-hydroxyvitamin D levels and decrease high 25-hydroxyvitamin D levels.

However, assuming the conclusions of this study to be true, it has some interesting implications:

  • If you are taking a vitamin D supplement, you should probably make sure that you are also getting the DV (400 mg) of magnesium from diet plus supplementation.
  • If you are taking a calcium supplement, you should check that it also provides a significant amount of magnesium. If not, change supplements or make sure that you get the DV for magnesium elsewhere.
  • I am suggesting that you shoot for the DV (400 mg) of magnesium rather than reading every label and calculating the calcium to magnesium ratio. The “ideal” ratio of 2.3 to 1 is hypothetical at this point. A supplement providing the DV of both calcium and magnesium would have a calcium to magnesium ratio of 2.5, and I would not fault any manufacturer for providing you with the DV of both nutrients.
  • If you are taking high amounts of calcium, I would recommend a supplement that has a calcium to magnesium ratio of 2.5 or less.
  • If you are considering a magnesium supplement to optimize your magnesium status, you should be aware that magnesium can cause gas, bloating, and diarrhea. I would recommend a sustained release magnesium supplement.
  • Finally, whole grains and legumes are among your best dietary sources of magnesium. Forget those diets that tell you to eliminate whole food groups. They are likely to leave you magnesium-deficient.

Even if the conclusions of this study are not confirmed by subsequent studies, we need to remember that magnesium is an essential nutrient with many health benefits and that most Americans do not get enough magnesium in their diet. The recommendations I have made for optimizing magnesium status are common-sense recommendations that apply to all of us.

 

The Case For Holistic Supplementation

 

magnesium optimize vitamin d case for holistic supplementationThis study is one of many examples showing that a holistic approach to supplementation is superior to a “magic bullet” approach where you take individual nutrients to solve individual problems. For example, in the case of magnesium and vitamin D:

  • If you asked most nutrition experts and supplement manufacturers whether it is important to provide magnesium along with vitamin D, their answer would likely be “No”. Even if they are focused on bone health, they would be more likely to recommend calcium along with vitamin D than magnesium along with vitamin D.
  • If your doctor has tested your 25-hydroxyvitamin D levels and recommended a vitamin D supplement, chances are they didn’t also recommend that you optimize your magnesium status.
  • Clinical studies investigating the benefits of vitamin D supplementation never ask whether magnesium intake is optimal.

That’s because most doctors and nutrition experts still think of nutrients as “magic bullets.” I cover holistic supplementation in detail in my book “Slaying The Supplement Myths.”  Other examples that make a case for holistic supplementation that I cover in my book include:

  • A study showing that omega-3 fatty acids and B vitamins may work together to prevent cognitive decline. Unfortunately, most studies looking at the effect of B vitamins on cognitive decline have not considered omega-3 status and vice versa. No wonder those studies have produced inconsistent results.
  • Studies looking at the effect of calcium supplementation on loss of bone density in the elderly have often failed to include vitamin D, magnesium, and other nutrients that are needed for building healthy bone. They have also failed to include exercise, which is essential for building healthy bone. No wonder some of those studies have failed to find an effect of calcium supplementation on bone density.
  • A study reported that selenium and vitamin E by themselves might increase prostate cancer risk. Those were the headlines you might have seen. The same study showed Vitamin E and selenium together did not increase prostate cancer risk. Somehow that part of the study was never mentioned.
  • A study reported that high levels of individual B vitamins increased mortality slightly. Those were the headlines you might have seen. The same study showed that when the same B vitamins were combined in a B complex supplement, mortality decreased. Somehow that observation never made the headlines.
  • A 20-year study reported that a holistic approach to supplementation produced significantly better health outcomes.

In summary, vitamins and minerals interact with each other to produce health benefits in our bodies. Some of those interactions we know about. Others we are still learning about. When we take high doses of individual vitamins and minerals, we create potential problems.

  • We may not get the full benefit of the vitamin or mineral we are taking because some other important nutrient(s) may be missing from our diet.
  • Even worse, high doses of one vitamin or mineral may interfere with the absorption or enhance the excretion of another vitamin or mineral. That can create deficiencies.

The same principles apply to our diet. I mentioned earlier that whole grains and legumes are among the best dietary sources of magnesium. Eliminating those two foods from the diet increases our risk of becoming magnesium deficient. And, that’s just the tip of the iceberg. Any time you eliminate foods or food groups from the diet, you run the risk of creating deficiencies of nutrients, phytonutrients, specific types of fiber, and the healthy gut bacteria that use that fiber as their preferred food source.

The Bottom Line

 

A recent study suggests that optimal magnesium status may be important for optimizing 25-hydroxyvitamin D status. This is one of many examples showing that a holistic approach to supplementation is superior to a “magic bullet” approach where you take individual nutrients to solve individual problems. For example, in the case of magnesium and vitamin D:

  • If you asked most nutrition experts and supplement manufacturers whether it is important to provide magnesium along with vitamin D, their answer would likely be “No.”  Even if they are focused on bone health, they would be more likely to recommend calcium along with vitamin D than magnesium along with vitamin D.
  • If your doctor has tested your 25-hydroxyvitamin D levels and recommended a vitamin D supplement, chances are he or she did not also recommend that you optimize your magnesium status.
  • Clinical studies investigating the benefits of vitamin D supplementation never ask whether magnesium intake is optimal. That may be why so many of those studies have failed to find any benefit of vitamin D supplementation.

I cover holistic supplementation in detail in my book “Slaying The Supplement Myths” and provide several other examples where a holistic approach to supplementation is superior to taking individual supplements.

In summary, vitamins and minerals interact with each other to produce health benefits in our bodies. Some of those interactions we know about. Others we are still learning about. Whenever we take high doses of individual vitamins and minerals, we create potential problems.

  • We may not get the full benefit of the vitamin or mineral we are taking because some other important nutrient(s) may be missing from our diet.
  • Even worse, high doses of one vitamin or mineral may interfere with the absorption or enhance the excretion of another vitamin or mineral. That can create deficiencies.

The same principles apply to what we eat. For example, whole grains and legumes are among the best dietary sources of magnesium. Eliminating those two foods from the diet increases our risk of becoming magnesium deficient. And, that’s just the tip of the iceberg. Any time you eliminate foods or food groups from the diet, you run the risk of creating deficiencies.

For more details about the current study and what it means to you read the article above.

 

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

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