animal protein

What Kind Of Protein Is Best For Strength?

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What Kind Of Protein Is Best For You?

Author: Dr. Stephen Chaney 

Sport DrinkEvery bodybuilder “knows” that whey is the best protein for building strong muscles. After all, it:

  • Is absorbed more rapidly than some other proteins.
  • Contains all nine essential amino acids.
  • Is naturally rich in leucine, a branched chain amino acid that stimulates increased muscle mass.

However, as someone who is not a vegan but who follows the vegan literature, I frequently come across testimonials from bodybuilders and elite athletes who say they get all the strength and muscle mass they need from plant proteins.

I’ve always assumed they must have dietitians designing the perfect plant protein diet for them. But a recent study surprised me. It challenged that assumption.

Before I talk about this study, let me change our focus. Most of us will never be bodybuilders or elite athletes, but all of us face a common challenge. We all tend to lose muscle mass as we age, something referred to as sarcopenia. I have discussed this in a previous issue of “Health Tips From the Professor”.

Simply put, sarcopenia results in:

  • Loss of muscle strength. Even the simple act of picking up a grandchild or a bag of groceries can become problematic.
  • Increased risk of falls and fractures.
  • Lower quality of life.

Sarcopenia is a major health issue for those of us in our golden years. If you are younger, it is a concern for your parents or grandparents. Sarcopenia is a health issue that affects everyone.

In my previous article I discussed the role of adequate protein intake and exercise in preventing age-related sarcopenia. But I did not discuss what kind of protein was best for preventing muscle loss, and the frailty that comes with it, as we age.

The article (EA Struijk et al, Journal of Cachexia, Sarcopenia and Muscle, 13: 1752-1761, 2022) I will discuss today suggests that plant protein is best for preventing frailty in women as they age. It’s a surprising conclusion, so join me as I evaluate this study.

How Was This Study Done?

Clinical StudyThe data for this study came from the Nurses Health Study which started in 1976 with 121,700 women nurses and is still ongoing. This study followed 85, 871 female nurses for an average of 22 years starting when they were 60.

Food frequency questionnaires were administered to the participants in the study every four years starting in 1980. The questionnaires were used to calculate:

  • Total calories consumed.
  • Percent of calories from protein, carbohydrate, and fat.
  • Percent of calories from different kinds of protein.
  • The overall quality of the diet.
  • Saturated fat, polyunsaturated fat, cholesterol, and alcohol intake.

For this study the investigators used the cumulative average values from all questionnaires completed by participants in the study from age 60 until the onset of frailty.

Frailty was assessed every four years starting in 1992 using something called the FRAIL scale. The FRAIL scale defines frailty based on five self-reported criteria: fatigue, low strength, reduced aerobic capacity, having 5 or more chronic illnesses, and recent significant unintentional weight loss.

  • It is important to note that strength is only one of the five criteria used to identify frailty, although decreased muscle mass can contribute to lack of energy and reduced aerobic activity.
  • It is also worth pointing out that multiple studies have shown that primarily plant-based diets are associated with a decrease in chronic diseases.

I will come back to both of these points when I discuss the results of this study.

What Kind Of Protein Is Best For Strength? 

I will start with the “big picture” results from this study and then cover some of the important details.

Average intake of:

  • Total protein was 18.3% of calories consumed.
  • Animal protein was 13.3% of calories consumed.
  • Plant protein was 5.0% of calories consumed.
  • Dairy protein was 3.8% of calories consumed.

When protein intake was divided into quintiles (5 equal parts) and women consuming the most protein were compared to those consuming the least protein for an average of 22 years:

  • Those consuming the most total protein had a 7% increased risk of developing frailty.
  • Those consuming the most animal protein had a 7% increased risk of developing frailty. (It is perhaps not surprising that the results were essentially the same for total and animal protein since animal protein was 73% of the total protein consumed by women in this study.)
  • Those consuming the most plant protein had a 14% decreased risk of developing frailty.
  • Consumption of dairy protein did not affect frailty.

Substituting as little as 5% of calories of plant protein for:

  • Dairy protein decreased the risk of developing frailty by 32%.
  • Animal protein decreased the risk of developing frailty by 38%.
  • Non-dairy animal protein (meat, fish, and eggs) decreased the risk of developing frailty by 42%.

In addition, substituting as little as 5% of calories of dairy protein for non-dairy animal protein decreased the risk of developing frailty by 14%.

But, as I said above, the frailty scale used in this study included the criteria of developing 5 or more chronic illnesses, and long-term consumption of plant protein is known to reduce the risk of developing chronic illnesses. So, it is important to break the study down into its component parts. When that was done the statistically significant results were:

  • Those consuming the most total protein had a 7% increased risk of low strength and a 25% increased risk of developing 5 or more chronic diseases.
  • Those consuming the most animal protein had a 9% increased risk of low strength and a 35% increased risk of developing 5 or more chronic diseases.
  • Those consuming the most plant protein had an 18% decreased risk of low strength. (It is interesting to note that plant protein consumption did not have a statistically significant effect on the development of chronic diseases in this study. That suggests that the “protective” effect of plant protein may simply be due to the absence of animal protein from the diet.)
  • Consumption of dairy protein did not affect any of the frailty criteria.

Finally, prevention of strength loss due to age-related sarcopenia is known to require exercise as well as adequate protein intake.

So, it was somewhat surprising that no difference in the association between protein intake and frailty was seen in women with high physical activity compared with those with lower physical activity levels. However, this may be because the range in activity level between the women in this study was relatively small. There didn’t appear to be a significant number of “gym rats” among the women in this study.

What Kind Of Protein Is Best For You?

Questioning WomanOne take-away from this study is clear. If you are a woman and want to minimize sarcopenia (loss of muscle mass and strength as you age), plant protein is an excellent choice.

  • A variety of plant proteins is best, so you get all the essential amino acids.
  • You don’t need to become a vegan. This study showed that replacing as little as 5% of your calories from animal protein with plant protein can have a significant benefit. Any healthy primarily plant-based diet will do.
  • This study enrolled only women aged 60 or above, so we don’t know whether the results apply to men or to younger women.

We don’t know why plant protein is better than animal protein at preventing age-related sarcopenia.

  • It could be because primarily plant-based diets are anti-inflammatory, and inflammation plays a role in sarcopenia.
  • Or it could be because primarily plant-based diets reduced the risk of chronic diseases, and chronic diseases can lead to loss of strength.

To be clear, this is a study that focuses on the type of protein that is best for long-term health and strength as we age. This is not a study of the best protein for increasing muscle mass following a workout.

  • Multiple studies show that whey protein can be a good post-workout choice.
  • However, other studies show that plant protein can also be a good post-workout choice if extra leucine is added to make it equivalent to whey protein in terms of leucine content.

The Bottom Line

You have probably heard that it is all downhill after age 30. But it doesn’t have to be.

One of the downhill slopes we all face is something called sarcopenia (age-related muscle loss). The resulting loss of strength and agility can severely impact our quality of life in our golden years.

We can prevent sarcopenia with the combination of a high protein diet and resistance training (weight bearing exercise).

But what kind of protein is best? In this issue of “Health Tips From the Professor” I review a large, well-designed study that suggests plant protein is the best choice for women if they wish to reduce age-related muscle loss and the weakness that comes with it.

For more details about the study and what it means for you, read the article above.

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

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My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

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About The Author

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Our Gut Bacteria Are What We Eat

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We Grow What We Eat

Author: Dr. Stephen Chaney

BacteriaThe subtitle of this week’s “Health Tips From the Professor” is “We Grow What We Eat”.

No, this is not about each of us starting a backyard garden and literally growing what we eat – although that would probably be a good idea for most of us. I’m actually talking about the bacteria that we “grow” in our intestine.

Most of you probably already know about the concept of “good” and “bad” intestinal bacteria.

Evidence suggests that the “bad” bacteria and yeast in our intestine can cause all sorts of adverse health effects:

  • There is mounting evidence that they can compromise our immune system.
  • There is also evidence that they can create a “leaky gut” (you can think of this as knocking holes in our intestinal wall that allow partially digested foods to enter the circulation where they can trigger inflammation and auto-immune responses).
  • There is some evidence that they can affect brain function and our moods.
  • They appear to convert the foods that we eat into cancer causing chemicals which can be absorbed into the bloodstream.
  • Studies in mice even suggest that they can make us fat.

The list goes on and on…

The “good bacteria” are thought to crowd out the “bad” bacteria and prevent many of the health problems they cause.

In case you’re thinking that it seems a bit far-fetched to think that our intestinal bacteria could affect our health, let me remind you that we have about 100 trillion bacteria in our intestine compared to about 10 trillion cells in our body. They outnumber us 10 to 1.

For years we have thought of “bad” bacteria and yeast as originating from undercooked, spoiled or poorly washed foods that we eat and the “good” bacteria as originating from foods like yogurt and probiotic supplements.

But most of us have not thought that the kinds of foods we choose to eat on a daily basis can affect the kinds of bacteria we “grow” in our intestine – until now. You’ve heard for years that “We are what we eat”. Well it now appears that we also “grow what we eat”. I’m referring to a recent study by G. D. Wu et al (Science, 334: 105-108, 2011).

Our Gut Bacteria Are What We Eat

I’m going to get a bit technical here (Don’t worry. There won’t be a quiz). Scientists refer to the population of bacteria in our intestines as our “microbiome”. Previous studies have shown that people from all over the world tend to have one of two distinct microbiomes (populations of bacteria) in their intestines – Bacteroides or Prevotella. [Again, don’t let the specialized scientific terminology scare you. These are just the names scientists have given to these two distinctive populations of intestinal bacteria].

What this study showed was that people who habitually consumed high-fat/low-fiber diets (diets containing predominantly animal protein and saturated fats) tended to have the Bacteroides bacteria in their intestine, while people who habitually consumed low-fat/high-fiber diets (diets that are primarily plant based and are high in carbohydrate and low in meat and dairy) tended to have the Prevotella bacteria in their intestine. And surprisingly this appears to be independent of sex, weight and nationality.

Is This Important?

The research defining these two distinct microbiomes (populations of intestinal bacteria) and showing that they are influenced by what we eat is very new. At this point in time we know relatively little about the health benefits and risks associated with the Bacteroides and Prevotella microbiomes.

For example:

  • Most of the studies on the health effects of “bad intestinal bacteria” were based on the identification of one or two “bad bacteria” in the gut – not on the hundreds of bacterial species found in the Bacteroides microbiome. So we can’t say for sure that the Bacteriodes microbiome found in people with diets high in animal protein and saturated fats will cause the same health problems as the “bad bacteria”. Nor do we know for sure how important a role the Bacteriodes microbiome plays in the health consequences of consuming that kind of diet.
  • Similarly, many of studies on the health benefits of “good intestinal bacteria” have been based on probiotic supplements containing one or two bacterial species – not the hundreds of bacterial species found in the Prevotella microbiome. So we can’t really say if probiotics or even the Prevotella microbiome will convey the same health benefits seen in populations who consume vegetarian diets.

However, now that do we know that we “grow what we eat” there are numerous studies ongoing to define the benefits and risks associated with each type of bacterial population.

For example, I shared a study with you recently which shows that the intestinal bacteria in people who eat a lot of animal protein convert carnitine (which is also found in meat) to a compound called TMAO, which may increase the risk of heart attacks, and that the conversion of carnitine to TMAO does not occur in people who consume a vegetarian diet ( see “Does Carnitine Increase Heart Disease Risk”)

Stay tuned! I’ll keep you updated as more information becomes available.

The Bottom Line:

Most of the studies I report on are ones that you can act on right away. This one is different. This study introduces a whole new concept – one that raises as many questions as it answers. This makes us ask those “what if” questions.

1)     Previous studies have shown that most people have one of two different kinds of microbiomes (populations of bacteria) in their intestines. This study showed that diets high in animal protein and fat favored one kind of intestinal microbiome, while diets low in fat and high in fiber from fruits & vegetables favored another type of intestinal microbiome.

2)     With a few exceptions we don’t know yet how important a role these intestinal microbiomes play in determining the health consequences of different diets. However, because our intestinal bacteria outnumber the cells in our body by 10:1, it is tempting to ask “What if?”

3)     We also don’t yet know the extent to which probiotics (either from foods or supplements) can overcome the effects of a bad diet on our intestinal microbiome, but it is tempting to ask “What if?”

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 High Protein Diets Cause Cancer?

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How Much Protein Should We Eat?

Author: Dr. Stephen Chaney

Animal Protein FoodsThe recent headlines suggesting that high protein diets may cause cancer, diabetes and premature death in middle aged Americans are downright scary. You are probably asking yourself:

  • “Is this new information?”
  • “Does this apply to me?”
  • “Should I radically change what I eat?”

In this issue of “Health Tips From the Professor” I will address each of these questions.

Do High Protein Diets Cause Cancer?

The study in question (Levine et al., Cell Metabolism, 19: 407-417, 2014) suggested that high protein diets were associated with increased risk of cancer, diabetes and premature death in Americans in the 50-65 age range. I will touch on all three of these observations, but it is the increased risk of cancer that generated the most headlines – and the most concern (The consequences of diabetes take years to manifest, and death seem to be a more distant concern for most people. Cancer is immediate and personal).

The study looked at 6,381 adults aged 50 and older (average age 65) from the NHANES III data base. (NHANES is a comprehensive database collected by the Centers for Disease Control and Prevention that consists of surveys and physical examinations and is designed to be representative of the health and nutritional status of the US population.)

The data collected consisted of a single diet questionnaire conducted when the subjects were enrolled in the study. Based on the diet questionnaire the authors of the study divided the group into those with low protein intake (<10% of calories), those with moderate protein intake (10-19% of calories) and those with high protein intake (>20% of calories). Overall death and mortality from various diseases over the next 18 years was obtained by linking the NHANES data with the National Death Index.

Based on preliminary data suggesting that the age of the population might influence the results (I won’t go into details here) the authors of the study decided to subdivide the dataset into people aged 50-65 and people over 65. When they did that, they came to the following conclusions:

1)     In the 50-65 age group diets high in animal protein were associated with a:

  • 45% increase in overall mortality
  • 4-fold increase in cancer death risk
  • 4-fold increase in diabetes death risk.

Diets with moderate protein intake were associated with intermediate increases in risk. Surprisingly, there was no increase in cardiovascular disease risk.

Protein Shakes2)     When they looked at people in the 50-65 age group consuming diets high in vegetable protein:

  • the increased overall mortality and increased in cancer mortality disappeared
  • the increased diabetes mortality was still seen.

3)     In the 65+ age group high protein diets were associated with a:

  • 28% decrease in overall mortality
  • 60% decrease in cancer mortality.

The increased risk of diabetes related deaths was still observed. The authors did not distinguish between animal and vegetable protein in the over 65 age group.

All of that may seem to be a bit too complicated. At the risk of gross oversimplification I would summarize their message as follows:

  • Diets high in animal protein may be bad for you if you are in the 50-65 age range, but might actually be good for you if you are over 65.
  • Diets high in vegetable protein appear to be good for anyone over age 50 (The study didn’t look at younger age groups).

Is This New Information?

Let’s start by assuming that the conclusions of the authors are correct (more about that below).

When you boil their message down to its simplest components, the information isn’t particularly novel.

  • The idea that vegetable proteins may be better for you than animal proteins has been around for decades. There are a number of studies suggesting that diets high in animal protein increase the risk of cancer, heart disease, diabetes and overall death – although it is still not clear whether it is the animal protein itself or some other characteristic of populations consuming mostly animal protein that is the culprit.
  • Evidence has been accumulating over the past decade or so that protein needs increase as we age, so it is not surprising that this study found high protein diets to be beneficial for those of us over age 65.

What Do Other Experts Say?

ScientistSince this study has been released it has been roundly criticized by other experts in the field. Let me sum up their four main criticisms and add one of my own.

1)     The protein intake data were based on a single dietary survey taken at the beginning of an 18 year study. The authors stated that a single dietary survey has been shown to be a pretty accurate indicator of what an individual is eating at the time of the survey. However, it is problematic to assume that everyone’s diet remained the same over an 18 year period.

2)     The choice of less than 10% of calories from protein is also problematic. According to the Institute of Medicine standards anything below 10% is defined as inadequate protein intake, which can have long term health consequences of its own.

More importantly, only 7% of the population being studied (437 individuals) fell into this group. This is the baseline group (or put another way, the denominator for all of the comparisons). The conclusions of this study were based on comparing the other two groups to this baseline, and there were too few individuals in this group to be confident that the baseline is accurate.

This does not necessarily invalidate the study, but it does decrease confidence in the size of the reported effect – so forget the reported numbers like 45% increase in mortality and 4-fold increase in cancer deaths. They probably aren’t accurate.

3)     The number of people in this study who died from diabetes was exceedingly small (68 total) and most of them already had diabetes when the study began. The experts concluded that the numbers were simply too low to draw any conclusions about protein intake and diabetes related deaths, and I agree with them.

4)     While the study controlled for fat intake and carbohydrate intake, it did not control for weight. That is a huge omission. Overweight is associated with increased risk of cancer, diabetes and death, and vegetarians tend to weigh less than non-vegetarians.

5)     I would add that there are many other differences between vegetarians and non- vegetarians that could account for most of the differences reported between diets high in animal and vegetable protein. For example:

  • Vegetarians tend to be more health conscious and thus they tend to exercise more, consume more fiber, consume more fruits and vegetables, consume less fried food, and consume less processed and convenience foods – all of which are associated with decreased risk of cancer, diabetes and death.

The Bottom Line:

This is not a particularly strong study. Nor is it particularly novel. In fact, when you strip away the scary headlines and focus on what the data really show, the conclusions aren’t that different from what nutrition experts have been saying for years.

1)     This study suggests that if you are in the 50-65 age range, diets high in animal protein may not be good for you (this study focused on increased risk of cancer death and overall mortality. Other studies have suggested that diets high in animal protein may increase the risk of cardiovascular death).

This is not a new idea. These data are consistent with a number of other studies. However, none of these studies adequately assess whether the increased risk is from the animal protein alone or from other characteristics of populations that consume a lot of animal protein.

2)     This study also suggests that diets high in vegetable protein do not increase either cancer risk or all cause mortality. That’s also not new information. We’ve known for years that people who consume primarily vegetable protein appear to be healthier. Once again, it is not clear whether it is the vegetable protein itself that is beneficial or whether the benefit is due to other characteristics of populations who consume a lot of vegetable protein.

3)     Does that mean that you need to become a vegetarian? It probably reflects my personal bias, but I am reminded of a Woody Allen Quote: “Vegetarians don’t live longer. It just seems that way”. I am also encouraged by studies suggesting that most of the health benefits of vegetarianism can be achieved by diets that consist of around 50% vegetable protein.

I would never discourage anyone from becoming a vegetarian, but if you aren’t ready for that, I would highly recommend that you aim for at least 50% vegetable protein in your diet.

4)     Finally, this study suggests that a high protein diet is beneficial for people over 65. This is also not a completely novel idea. It is consistent with a lot of recent research.

My advice to those of you who, like me, are over 65 is to pay attention to high protein foods and make sure that they are an important part of your diet. I’m not suggesting that you go for the double bacon cheeseburger just because you are over 65. I would still aim for a significant percentage of vegetable protein as a part of a healthy diet at any age.

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.

Health Tips From The Professor