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 Protein Supplement Timing Matter?

Posted May 15, 2018 by Dr. Steve Chaney

How Do You Gain Muscle Mass & Lose Fat Mass?

Author: Dr. Stephen Chaney

 

protein supplement timingMost of what you read about protein supplements on the internet is wrong. That is because most published studies on protein supplements:

  • Are very small
  • Are not double blinded.
    • Both the subjects and the investigators knew who got the protein supplement.
  • Are done by individual companies with their product.
    • You have no idea which ingredients are in their product are responsible for the effects they report.
    • You have no idea how their product compares with other protein products.
    • There is no standardization with respect to the amount or type of protein or the addition of non-protein ingredients.

Because of these limitations there is a lot of misleading information on the benefits of protein supplements timing and maximal benefit. Let’s start by looking at why people use protein supplements. Let’s also look at what is generally accepted as true with respect to the best supplement timing.

There are 4 major reasons people consume protein supplements:

  • Enhance the muscle gain associated with resistance training: In this case, protein supplements are customarily consumed concurrently with the workout.
  • Preserve muscle and accelerate fat loss while on a weight loss diet: In this case, protein supplements are customarily consumed with meals or as meal replacements.
  • Provide a healthier protein source. In this case, protein supplements are customarily consumed with meals in place of meat protein.
  • Prevent muscle loss associated with aging or illness. There is no customary pattern associated with this use of protein supplements.

How good are the data supporting the customary timing of protein supplementation? The answer is: Not very good. The timing is based on a collection of weak studies which do not always agree with each other.

The current study  (J.L. Hudson et al, Nutrition Reviews, 76: 461-468, 2018 ) was designed to fill this void in our knowledge. It is a meta-analysis that compares all reasonably good studies that have looked at the effect of protein supplement timing on weight gain or loss, lean muscle mass gain, fat loss, and the ratio of lean muscle mass to fat mass.

How Was The Study Done?

The authors started by doing a literature search of all studies that met the following criteria:

  • The study was a randomized control trial with parallel design. This means that study contained a control group. It does not mean that the investigators or subjects were blinded with respect to which subjects used a protein supplement and which did not.
  • The subjects were engaged in resistance training.
  • The study lasted 6 weeks or longer.
  • Reliable methods were used to measure body composition (lean muscle mass and fat mass).
  • The subjects were healthy and at least 19 years old.
  • There was no restriction on the food the subjects consumed.

The authors started with 2074 published studies and ended up with 34 that met all their criteria. They then separated the studies into two groups – those in which the protein supplements were used with meals and those in which the protein supplements were used between meals.

Both groups were diverse.

  • Group 1 included subjects who consumed their protein supplement with their meal and those who consumed their protein supplement as a meal replacement.
  • Group 2 included subjects who consumed their protein supplement concurrent with exercise (usually immediately after exercise) and those who consumed their protein supplement at a fixed time of day not associated with exercise.

Does Protein Supplement Timing Matter?

 

protein supplement timing workoutsBecause the individual studies were very diverse in the way they were designed, the authors could not calculate a reliable estimate of how much lean muscle mass was increased or fat mass was decreased. Instead, they calculated the percentage of studies showing an increase in lean muscle mass or a decrease in fat mass.

When the authors compared protein supplements consumed with meals versus protein supplements consumed between meals:

  • Weight gain was observed in 56% of the studies of protein supplementation with meals compared to 72% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • An increase in lean muscle mass was observed in 94% of the studies of protein supplementation with meals compared to 90% of the studies of protein supplementation between meals. In other words, timing of protein supplementation did not matter with respect to increase in muscle mass.
  • A loss of fat mass was observed in 87% of the studies of protein supplementation with meals compared to 59% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • An increase in the ratio of lean muscle mass to fat mass was observed in 100% of the studies of protein supplementation with meals compared to 87% of the studies of protein supplementation between meals. In short, protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean muscle mass to fat mass.

The following seem to suggest protein supplement timing matters:

The authors pointed out that their findings were consistent with previous studies showing that when protein supplements are consumed with a meal they displace some of the calories that otherwise would have been consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors stated that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

The others concluded: “Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean [muscle] mass.”

What Are The Limitations Of The Study?

Meta-analyses such as this one, are only as good as the studies included in the meta-analysis. Unfortunately, most sports nutrition studies are very weak studies. Thus, this meta-analysis is a perfect example of the “Garbage In: Garbage Out (GI:GO)” phenomenon.

For example, let’s start by looking at what the term “protein supplement” meant.

  • Because the studies were done by individual companies with their product, the protein supplements in this meta-analysis:
    • Included whey, casein, soy, bovine colostrum, rice or combinations of protein sources.
    • Were isolates, concentrates, or hydrolysates.
    • Contained various additions like creatine, amino acids, and carbohydrate.
  • As I discuss in my book, Slaying the Food Myths, previous studies have shown that optimal protein and leucine levels are needed to maximize the increase in muscle mass and decrease in fat mass associated with resistance exercise. However, neither protein nor leucine levels were standardized in the protein supplements included in this meta-analysis.
  • Previous studies have shown that protein supplements that have little effect on blood sugar levels (have a low glycemic index) are more likely to curb appetite. However, glycemic index was not standardized for the protein supplements included in this meta-analysis.

protein supplement timing workout peopleIn short, the conclusions of this study might be true for some protein supplements, but not for others. We have no way of knowing.

We also need to consider the composition of the two groups.

  • Protein supplements used as meal replacements are more likely to decrease weight and fat mass than protein supplements consumed with meals. Yet, both were included in group 1.
  • Some studies suggest that protein supplements consumed concurrent with resistance exercise are more likely to increase muscle mass than protein supplements consumed another time of day. Yet, both are included in group 2. We also have no idea whether the meals with protein supplements in group 1 were consumed shortly after exercise or at an entirely different time of day.

This was the most glaring weakness of the study because it was completely avoidable. The authors could have grouped the studies into categories that made more sense.

In other words, there are multiple weaknesses that limit the predictive power of this study.

What Can We Learn From This Study?

Despite its many limitations, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, most of us are using protein supplements to lose weight or to increase our lean mass to fat mass ratio. Simply put, we are either trying to lean out (shape up) or lose weight. And, we want to lose that weight primarily by getting rid of excess fat. For us, calories do matter. With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

 

The Bottom Line:

 

A recent study looked at the optimal timing of protein supplements consumed by subjects who were engaged in resistance exercise. Specifically, the study compared protein supplements consumed with meals versus protein supplements consumed between meals on weight, lean muscle mass, fat mass, and the ratio of lean muscle mass to fat mass. The study reported:

  • Protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • Timing of protein supplementation did not matter with respect to increase in muscle mass.
  • Protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • Protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean mass to fat mass.

The authors pointed out that their findings were consistent with previous studies showing that when a protein supplement was consumed with a meal it displaces some of the calories that would have been otherwise consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors said that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

As discussed in the article above, the study has major weaknesses. However, despite its many weaknesses, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, for those of us who are using protein supplements to lose weight or to increase our lean mass to fat mass ratio, calories do matter.  With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

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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