How Much Protein Do Post-Menopausal Women Need?

March 19, 2024 by Dr. Steve Chaney

Does The Design Of The Protein Supplement Matter?

Author: Dr. Stephen Chaney

You’ve probably heard the saying, “It’s all downhill after 30”. That’s a particularly gloomy way of looking at it, but Father Time does take a toll on our body. I’m going to focus on age-related loss of muscle mass today, a physiological process called sarcopenia.

There are three factors that influence the rate at which we lose muscle mass as we age:

1) Our physiology changes. Our bodies break down our protein stores more rapidly and we have a harder time utilizing the protein in our diet to replenish those protein stores.

2) We become less active. In some cases, this reflects physical disabilities, but all too often it is because we are not giving weight-bearing exercises the proper priority in our busy lives.

3) Our diets become inadequate. The major driver of this phenomenon is loss of appetite which results in decreased caloric intake. However, physical disability, isolation, and insufficient income also contribute.

Sarcopenia in turn 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.

Obviously, 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.

But what can be done to prevent sarcopenia? We can’t change our physiology, but we can change our activity level and our diet. Weight-bearing exercise tugs on our muscle fibers. That stimulates those fibers to incorporate protein into new muscle cells. It is no wonder that weight-bearing exercise is recommended for preventing sarcopenia.

What about diet? Are older adults getting enough protein in their diet to benefit from weight-bearing exercise? I have shared studies showing that older adults need more protein and higher levels of the amino acid leucine to benefit from their workouts.

But those studies were done with men. There have been no studies comparing younger and older women until now.

In this article, I discuss a recent study (CF McKenna et al, Journal of Applied Physiology, Feb 22, 2024 doi.org/10.1152/applphysiol.00886.2023) that asks how much protein is needed to stimulate muscle protein synthesis following a workout in post-menopausal women and compares it to the protein needs of younger women.

How Was The Study Done?

The investigators enrolled 16 post-menopausal women who were part of a much larger study investigating exercise and nutritional regimens that preserve and/or enhance muscle mass in women.

The women in this study were on average 60 years old with a BMI of 26 (overweight). They had no heart disease, dietary restrictions, and did not take any supplements that could affect protein metabolism.

They were compared to a cohort of pre-menopausal women (average age = 24, BMI = 25 (borderline overweight)) recruited from the same large study. The experimental protocol was the same for the pre-menopausal and post-menopausal cohorts.

The study design was what is called a parallel-group design. Simply put, one leg was exercised using a leg extension machine, while the other leg was rested. The rested leg served as the control for each participant in the study.

Participants were tested ahead of time to determine the “one-repetition maximum” (1RM) weight for complete leg extension for each participant.

On the day of the experiment participants arrived in the laboratory after an overnight fast. One iv line was inserted, and a labeled amino acid was infused into the bloodstream, so the investigators could measure new protein synthesis at any time during the 4-hour experiment. Another iv line was inserted, so the investigators could withdraw blood samples.

At the beginning of the experiment, each participant was given either a whey protein drink (whey protein isolate fortified with vitamins C, B1, B2, B3, folate, B6, and B12 and minerals calcium, magnesium, iron, zinc, and potassium) or water. They then performed a bout of single-leg extensions starting with a warm-up of 2 sets of repetitions at 30% 1RM followed by 3 sets of 12 repetitions at 65% 1RM with 90 seconds of rest provided between sets.

Immediately following exercise, muscle biopsies were collected from both legs (t=0). Muscles biopsies were also collected at 120 and 240 minutes after exercise. Blood samples were collected continually during the experiment.

Muscle tissue was isolated from each biopsy, and something called myofibrillar protein synthesis (protein synthesis in muscle fibers) was determined based on the amount of labeled amino acid incorporated into muscle protein. The amount of protein synthesis due to exercise was determined by subtracting the incorporation of labeled amino acid in muscle fibers in the rested leg from that in the exercised leg.

What Is Leucine?

Leucine is an essential amino acid. It is present in all dietary proteins, but it is more abundant in whey and soy protein than in some vegetable proteins.

Leucine is also one of three branched-chain amino acids (valine and isoleucine are the other two). If you are familiar with the weightlifting and body-building world, you will know that branched-chain amino acids are thought to be important for muscle gain. However:

It turns out that leucine is the only branched chain amino acid that stimulates muscle protein synthesis (Am J Physiol Endocrinol Metab 291: E381-E387, 2006). And protein is what gives muscles their strength and their bulk.

The other branched chain amino acids appear to play a supporting role in the quantities that occur naturally in most proteins. And adding extra valine and isoleucine to a protein supplement appears to reduce the effectiveness of leucine at stimulating muscle gain (Am J Physiol Endocrinol Metab 291: E381-E387, 2006).

What Have Previous Studies Shown?

With respect the amount of protein needed to optimize muscle gain after workouts, previous studies have shown that:

The optimal protein intake for maximizing muscle gain post workout is 15-20 gm for young men (Katsanos et al, Am J Clin Nutr 82: 1065-1073, 2005; Moore et al, Am J Clin Nutr, 89: 161-168, 2009) and 20-25 gm for older men (Symons et al, Am J Clin Nutr 86: 451-456, 2007).

More protein isn’t necessarily better. The effect of protein intake on post workout muscle gain maxes out at around 25 gm for young men and 30 gm for older men (Symons et al, J Am Diet Assoc 109: 1582-1586, 2009).

Whey protein is the best choice for enhancing muscle gain immediately after a workout. Other protein sources (soy, casein, chicken) are better choices for sustaining muscle gain over the next few hours.

A previous study by the authors of the present study showed that 15 gm of whey protein was sufficient to stimulate muscle protein synthesis in young women (average age 20). Thus, young women and young men both appear to benefit from 15 gm of protein after a workout.

How Much Protein Do Post-Menopausal Women Need?

This is a complex study, so let’s just start with the big takeaway from the study:

The same whey protein supplement that increased muscle mass in younger women failed to stimulate “cumulative muscle protein synthesis” [net increase in muscle mass] in post-menopausal women. (This was measured by determining net accumulation of labeled amino acids into the muscle fibers of the exercised leg compared to the rested leg.)

With that out of the way, we can focus on some less important findings:

There was a short-term (0-2h) transient increase in muscle protein synthesis following exercise with and without the whey protein supplement, but the result was not cumulative. In other words, the transient protein synthesis did not result in an increase in muscle mass.

There was a long-term (2-4h) transient increase in muscle protein synthesis following exercise for the group taking the whey protein supplement, but, again, the result was not cumulative. It did not result in a net increase in muscle mass.

In the group taking the whey protein supplement there was a transient increase in both insulin and leucine in the blood between 2 and 4 hours. Either or both could have driven the transient increase in protein synthesis observed during that same times.

In the words of the authors, “Ingestion of 15 gm whey protein failed to stimulate [net] myofibrillar (muscle) protein synthesis in post-menopausal women. While resistance exercise with and without feeding stimulate late (2-4 h) and early (0-2h) increases in myofibrillar protein synthesis, further exercise and nutritional manipulations may be necessary to robustly stimulate the skeletal muscle adaptive response to exercise.”

They went on to say that increased exercise intensity and/or increased protein intake may be necessary for post-menopausal women to maintain or increase muscle mass.

What Does This Study Mean For Post-Menopausal Women?

I should start by acknowledging that this was a small study, as are most studies in this field of research. In part this reflects the expense of these experiments and the lack of major government support. But it also reflects the difficulty in recruiting subjects for this kind of experiment. They are hooked up to two iv’s for over four hours and have three muscle biopsies removed from each leg during that time. That’s a pretty invasive experimental protocol.

With this limitation in mind, the biggest takeaway from this study is that post-menopausal women need more protein to build muscle mass than younger women. Young women, just like young men, can build muscle mass with as little as 15 gm of protein post-workout.

Unfortunately, this study did not determine how much protein post-menopausal women need to build muscle mass post-workout. And that is a critical question, because women typically have less muscle mass than men when sarcopenia starts to set in. Resistance (weight-bearing) exercise and adequate protein intake are key to preventing the debilitating effects of sarcopenia in post-menopausal women.

In their conclusion, the authors said that “…further exercise and nutritional manipulations may be necessary [to optimize the post-workout gain in muscle mass for post-menopausal women].”

From an exercise standpoint, the authors speculated that higher intensity exercise may be needed to increase muscle mass in post-menopausal women. However, the exercise protocol they used was based on public health recommendations for resistance training for older adults. A more rigorous exercise protocol might not be suitable for many post-menopausal women.

From a nutritional standpoint, they noted that a previous study had shown that 35 gm of protein post-workout was sufficient to build muscle mass in post-menopausal women. However, they considered 35 gm of protein to be a dangerously high intake for a single serving of protein for post-menopausal women. I concur.

In summary, we know that 15 gm of protein post-workout is too little for postmenopausal women, and while 35 gm of protein is sufficient, it is probably too much. Until further studies are performed in post-menopausal women, I would recommend the 20-25 gm of protein shown to support post-workout muscle gain in older men.

But it is not just the amount of protein that is important. The design of the protein supplement also matters.

Does The Design Of The Protein Supplement Matter?

While the amount of protein in a post-workout supplement is important, the design of the protein supplement also matters. While there are lots of crazy claims on the internet, there are two natural ways to maximize the effect of a protein supplement on muscle mass. Insulin and the amino acid leucine both drive muscle protein synthesis and help maximize post-workout muscle gain.

Recent research has shown that 2-3 gm of leucine (2 gm for young men; 3 gm for older men) is sufficient to maximize post workout muscle gain if protein levels are adequate (Am J Physiol Endocrinol Metab 291: E381-E387, 2006). We don’t know the corresponding leucine requirements for women, so we will need to assume they are similar.

- A 15-gram serving of whey protein isolate only provides 1.4 gm of leucine, far below what is likely to be needed to drive post-workout muscle gain in post-menopausal women.

- If you are a man over 50 or a post-menopausal woman, you should look for a post-workout protein supplement containing added leucine. And even younger adults will get “more bang for your buck” by choosing protein supplements with added leucine.

The insulin response is maximized when the carbohydrate to protein ratio is around 2.5 to 1. The manuscript did not list carbohydrates among the ingredients used in the whey protein supplement used in this study. But if it is like many whey protein supplements nowadays, it probably contained little or no carbohydrate.

- Although less popular in today’s low carbohydrate world, post-workout supplements with a high carbohydrate to protein ratio are also effective in maximizing post-workout muscle gain.

The Bottom Line

Sarcopenia (age-related muscle loss) is a major concern for older Americans. Sarcopenia can result 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 can be prevented by a combination of resistance exercise and adequate amounts of protein following the workout.

We know that older men require more protein than young men in a post-workout supplement designed to help them maximize the muscle gain associated with resistance exercise. But similar experiments had not been performed with women until now.

In the article above I share a study that shows that post-menopausal women need more protein than young women in a post-workout supplement. But the study did not determine how much protein they need.

I also discuss the amount of protein post-menopausal women likely need in a post-workout supplement, and how that protein supplement could be designed to maximize muscle gain and prevent sarcopenia.

For more information on this study and my recommendations 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.

Do Collagen Supplements Build Muscle?

August 24, 2021 by Dr. Steve Chaney

Could Collagen Supplements Make You Leaner?

Author: Dr. Stephen Chaney

Collagen supplements have been considered “vanity products”. Their largest market is people who want to have younger, more beautiful skin. And for many people, collagen delivers on this promise.

However, collagen plays many other roles in the body. It also helps rebuild tendons and ligaments. Many people take collagen supplements to reduce joint pain.

But could collagen supplements coupled with resistance training also build muscle and reduce fat? If so, that would be huge.

A recent study (D Zdzieblik et at, British Journal of Nutrition, 114: 1237-1245, 2015) suggested collagen supplements may do just that. This study showed that a collagen supplement plus resistance training increased lean muscle mass and decreased fat mass in elderly men (average age = 72).

If this finding is duplicated in future studies, it has significant health implications. Both men and women in their 70s lose muscle mass at a rapid rate (a process called sarcopenia). Anything that slows or reverses this process has the potential to extend high quality life and prolong their golden years.

But what about younger adults? Could a collagen supplement plus resistance training also help them build muscle and lose fat? This study (D Zdzieblik et at, International Journal of Environmental Research and Public Health, 18: 4837-4855, 2021) was designed to answer that question.

It was a randomized, placebo-controlled study comparing 15 g of collagen peptides with 15 g of whey protein, and a placebo (silicon dioxide).

How Was This Study Done?

The study recruited 120 middle-aged (average age = 50), overweight (average BMI = 30) men who were untrained (<60 minutes of exercise per week over the previous year). [In other words, the study recruited middle-aged couch-potatoes.]

The participants were asked to fill out a three-day diet analysis at the beginning and end of the 12-week study with the assistance of a nutritionist.

Average caloric intake was 2,600 calories/day.

Average protein intake was 104 grams/day. That is 30% higher than the recommended protein intake for men of that age and weight.

The macronutrient content of the diet was 16% protein, 37% fat, and 43% carbohydrate.

These values were not significantly different between groups and did not change during the study.

All participants participated in a one-hour training program three times per week. The training began with a 10-minute cardio exercise to warm up. That was followed by a three-set program consisting of horizontal leg presses (both legs), reverse crunches, lat-pull exercise, sit-ups, and chest presses with 1 to 2 min rest periods between sets. The intensity of exercise was gradually increased over the 12-week study.

The participants were randomly divided into three groups. After each workout they were given sachets containing 15 g of collagen peptides, 15 g of whey isolate, or 15 g of silicon dioxide (placebo). They were instructed to dissolve the powder in 8 ounces of water and drink it within one hour of the workout. They were also given the same sachets and instructed to take them at the same time of day for the days they were not working out.

Finally, the participants were instructed not to change their diet or physical activity apart from the intake of the powder in the sachets they were given and the one-hour training sessions.

Do Collagen Supplements Build Muscle?

All three groups had statistically significant:

Increases in percent lean muscle mass.

Decreases in percent fat mass.

Increases in leg muscle strength.

No surprises here. If you take a group of middle-aged couch-potatoes and put them in a strength training program, you will see increases in lean muscle mass, decreases in fat mass, and increases in muscle strength.

The real question was what was the effect of the collagen and whey protein supplements? This is where the results got really interesting.

The collagen peptide supplement gave a significantly greater increase in lean muscle mass and decrease in fat mass than the placebo. The increase in leg muscle strength was also greater than the placebo, but this difference was not statistically significant.

The whey protein supplement also increased lean muscle mass and decreased fat mass compared to the placebo, but these differences were not statistically different.

In other words, at the doses used in this study (see next section for discussion), the collagen supplement worked better than the whey protein supplement. Here is the actual data from the study:

Increase in percent lean muscle mass: collagen supplement = 7.4%, whey protein supplement = 5.8%. placebo = 5.0%.

Decrease in percent fat mass: collagen supplement = 15%, whey protein supplement = 11.5%, placebo = 10%.

In the words of the authors, “In conclusion, collagen peptide supplementation combined with resistance training was associated with a significantly greater increase in fat free mass and a decrease in fat mass compared with placebo. Resistance training combined with whey protein also had a positive impact on body composition, but the respective effects were more pronounced following the collagen peptide administration.”

Could Collagen Supplements Make You Leaner?

This study leaves lots of questions. Let me handle the main ones here.

What Are The Strengths and Weaknesses Of The Study?

The strengths are obvious. This was a well-design, randomized, placebo-controlled clinical trial, which is the gold standard for determining the efficacy of a treatment.

The weaknesses are also obvious. This was a very small clinical study. There is one previous study that showed the same benefit of collagen in an older age group. However, both studies were published by the same group of scientists. And these scientists were funded by the manufacturer of the collagen product used in the study. More and larger studies performed by other laboratories are needed to confirm this finding.

How Do Resistance Exercise, Whey Protein, And Collagen Stimulate Muscle Growth?

Muscle growth is stimulated by a regulatory pathway called mTOR that (among other things) regulates protein synthesis in muscle cells. For the purposes of this article, I will discuss 3 mechanisms for activating mTOR and increasing muscle protein synthesis.

#1: Resistance exercise (weight training) activates mTOR. That should come as no surprise. The main reason people do weight training is to increase strength and muscle mass. mTOR is the pathway that makes this possible.

#2: Whey protein is rich in the essential amino acid leucine, and leucine also stimulates the mTOR pathway.

Leucine is one of three branched chain amino acids. While all three branched chain amino acids have been traditionally credited with stimulating muscle protein synthesis, recent research has shown that only leucine is needed. The other two branched chain amino acids just play a supportive role. You only need enough of the them to make a complete protein.

While whey protein gets all the attention in the sports world, any complete protein with high levels of leucine has the same effect.

The effect of leucine and resistance training on the mTOR pathway are additive. That is why whey and other leucine-rich proteins enhance the effect of resistance exercise on both muscle mass and strength.

#3: Collagen does not contain enough leucine to activate the mTOR pathway. However, the authors have proposed another mechanism to account for collagen activation of the mTOR pathway.

Most proteins we eat are digested to their individual amino acids before they are absorbed. However, collagen is rich in an unusual amino acid called hydroxyproline that makes collagen resistant to our digestive enzymes.

Thus, collagen is not digested to individual amino acids, but to small peptides that are absorbed from our intestine.

One of these breakdown products, a dipeptide composed of glycine and hydroxyproline, has been shown to stimulate the mTOR pathway.

While this mechanism has not been proven, collagen does appear to enhance the effect of resistance exercise on both muscle mass and strength.

Collagen Only Has 8 Essential Amino Acids. How Could It Stimulate The Synthesis Of Muscle Protein, Which Requires 9 Essential Amino Acids?

The answer is simple. The people in this study were consuming 30% more than the recommended amount of protein in their diet in addition to the collagen supplement. They already had all the essential amino acids needed to synthesize muscle protein. The collagen supplement simply stimulated the rate of muscle protein synthesis by activating the mTOR pathway.

However, there are situations in which the 9^th essential amino acid could become important for muscle protein synthesis. Here are two examples

Vegans and strict vegetarians might not be getting enough protein in their diet. As I pointed out in a previous article vegan “experts” know how to get enough protein from their diet, but many vegan “novices” do not.

Older Americans are also at risk. They need extra protein in their diet to prevent sarcopenia (muscle loss) as they age. And some of them are on restrictive diets, either because of the latest fad or because of loss of income and/or mobility.

Why Did The Collagen Supplement Work Better Than Whey Protein In This Experiment?

Again, the answer is simple. Both collagen and leucine-rich proteins like whey enhance muscle protein synthesis by activating the mTOR pathway (see above). This study used the same amount of protein (15 g/day) for both collagen supplement and the whey protein supplement.

While 15 g/day appears to be optimal for the collagen supplement, the authors pointed out that previous studies suggest that the optimal dose for whey protein is closer to 20 g/day for middle-aged men.

So, I would ignore the apparent difference in effectiveness of the collagen and whey protein supplements.

The important conclusion is that both collagen and leucine-rich proteins like whey enhance the effect of resistance exercise on lean muscle mass to a similar extent. But they appear to do so by slightly different mechanisms.

What Does This Mean For You?

This study is intriguing. It suggests that collagen may have some tricks up its sleeve we didn’t know about.

It may do more than give you a healthy, youthful looking skin.

It may do more than help with achy joints.

Coupled with resistance exercise it may also help you increase muscle mass and reduce fat mass. It may make you leaner.

The Bottom Line

Collagen supplements have been considered “vanity products”. Their largest market is people who want to have younger, more beautiful skin. And for many people, collagen delivers on this promise.

However, collagen plays many other roles in the body. It also helps rebuild tendons and ligaments. Many people take collagen supplements to reduce joint pain.

But collagen may have other tricks up its sleeve. A recent study suggests that collagen supplements may enhance the effect of resistance exercise on increased muscle mass and reduced fat mass. It may make you leaner.

The study also concluded that both collagen and whey protein enhance the effect of resistance exercise on lean muscle mass to a similar extent. But they appear to do so by slightly different mechanisms.

Let me be clear. I am not recommending you take a collagen supplement to help you build muscle mass. I consider these results as preliminary, and we have good evidence that leucine-rich proteins plus resistance exercise helps build muscle mass.

However, if you are taking a collagen supplement for another reason and are working out, this could be an unexpected benefit.

For more details about this study and how collagen supplements may increase muscle mass, 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.

Does Leucine Trigger Muscle Growth?

January 28, 2014 by Dr. Steve Chaney

What Does The Perfect Post-Workout Protein Shake Look Like?

Author: Dr. Stephen Chaney

If you work out on a regular basis and read any of the “muscle magazines”, you’ve seen the ads. “Explode Your Muscles.” “Double Your Gains.” They all claim to have the perfect post-workout protein shake, backed by science. They all sound so tempting, but you know that some of them have to be scams.

I told you about some of the sports supplements to avoid in a previous “Health Tips From the Professor”. In this issue, I’m going to ask “What does the perfect post-workout protein shake look like?”

For years athletes have been using protein beverages containing branched chain amino acids after their workouts to maximize muscle gain and recovery. There was some science behind that practice, but the major questions were unanswered. Nobody really knew:

How much protein is optimal?

What kind of protein is optimal?

What amount of branched chain amino acids is optimal?

Are some branched chain amino acids more important than others?

Does the optimal amount of branched chain amino acids depend on the amount of protein?

As a consequence, after workout protein supplements were all over the map in terms of protein source, protein amount, branched amino acid amount and type of branched chain amino acids. Fortunately, recent research has clarified many of these questions.

How Much And What Kind Of Protein Do You Need?

Recent research has shown that the optimal protein intake for maximizing muscle gain post workout is 15-20 gm for young adults (Katsanos et al, Am J Clin Nutr 82: 1065-1073, 2005; Moore et al, Am J Clin Nutr, 89: 161-168, 2009) and 20-25 gm for older adults (Symons et al, Am J Clin Nutr 86: 451-456, 2007).

More protein isn’t necessarily better. The effect of protein intake on post workout muscle gain maxes out at around 25 gm for young adults and 30 gm for older adults (Symons et al, J Am Diet Assoc 109: 1582-1586, 2009).

Whey protein is the best choice for enhancing muscle gain immediately after a workout. Other protein sources (soy, casein, chicken) are better choices for sustaining muscle gain over the next few hours.

Does Leucine Trigger Muscle Growth?

It turns out that leucine is the only branched chain amino acid that actually stimulates muscle protein synthesis (Am J Physiol Endocrinol Metab 291: E381-E387, 2006). And protein is what gives muscles their strength and their bulk.

Recent research has shown that 2-3 gm of leucine (2 gm for young adults; 3 gm for older adults) is sufficient to maximize post workout muscle gain if protein levels are adequate (Am J Physiol Endocrinol Metab 291: E381-E387, 2006).

Unanswered Questions About Optimizing Muscle Gain Post-Workout

Do the other branched chain amino acids play a supporting role, or is leucine alone sufficient to drive post-workout muscle gain?

Can leucine still help maximize post-workout muscle gain if protein intake is inadequate? If so, how much leucine is needed?

Does Leucine Enhancement Improve Low Protein Shakes?

A recent study (Churchward-Venne et al, Am J Clin Nutr, 99: 276-286, 2014) seems to answer those two questions. The authors compared the effect of 5 protein-amino acid combinations on muscle protein synthesis in 40 young men (~21 years old) following unilateral knee-extensor resistance exercise. The protein shakes contained:

25 gm of whey protein, which naturally contains 3 gm of leucine (high protein)

6.25 gm of whey protein, which naturally contains 0.76 gm of leucine (low protein)

6.25 gm of whey protein with 3 gm of leucine (low protein, low leucine)

6.25 gm of whey protein with 5 gm of leucine (low protein, high leucine)

6.25 gm of whey protein with 5 gm of leucine + added isoleucine and valine (the other branched chain amino acids). (low protein, branched chain amino acids).

The results were clear cut:

The high protein shake (25 gm of protein) was far superior to the low protein shake (6.25 gm of protein) at enhancing post workout protein synthesis. This is consistent with numerous other published clinical reports.

Adding 3 gm of leucine to the low protein shake had no effect on post-workout protein synthesis, but 5 gm of added leucine made the low protein shake just as effective as the high protein shake at supporting post-workout protein synthesis.

In short, leucine can improve the effectiveness of a low protein shake, but you need more leucine than if you chose the high protein shake to begin with.

Adding extra branched chain amino acids actually suppressed the effectiveness of leucine at enhancing post-workout protein synthesis. These data suggest:

Leucine probably is the major amino acid responsible for the muscle gain reported in many of the previous studies with branched chain amino acids.

If the other branched chain amino acids play a supporting role in the muscle gain, the quantities that occur naturally in the protein are probably enough. Adding more may actually reduce the effectiveness of leucine at stimulating muscle gain.

While this is a single study, it is consist with numerous other recent clinical studies. It simply helps clarify whether leucine can increase the effectiveness of a low protein supplement. It also clarifies the role of branched chain amino acids.

Also, while this study focused on protein synthesis, numerous other studies have shown that optimizing post-workout protein and leucine intake results in greater muscle gain (for example, Westcott et al., Fitness Management, May 2008)

The Bottom Line

Research on post-workout nutrition to optimize muscle gain from the workouts has come a long way in recent years. It is now actually possible to make rational choices about the best protein supplements and foods to support your workouts.

If you are a young adult (17-30), you should aim for 15-20 gm of protein and about 2 gm of leucine after your workout.

If you are an older adult (50+), you should aim for 20-25 gm of protein and 3 gm of leucine after your workout.

If you are in between you are on your own. Studies haven’t yet been done in your age group, but it’s reasonable to assume that you should aim for somewhere between the extremes.

If you are getting the recommended amounts of whey protein, the leucine level will also be optimal. If you are using other protein sources you may want to choose ones with added leucine.

The research cited above shows that you can make a low protein supplement effective by adding lots of leucine, but that’s going to require artificial flavors and sweeteners to cover up the taste of that much leucine. I would recommend choosing one that provided adequate protein to begin with.

While the research in this area is still somewhat fluid, I would avoid protein supplements with added branched chain amino acids other than leucine. If the paper I cited above is correct you probably get all of the other branched chain amino acids you need from your protein and adding more may actually interfere with the effect of leucine on muscle gain.

I’d pretty much forget all the other “magic ingredients” in post-workout supplements. If you’re a novice there is some evidence that arginine and HMB may be of benefit, but if you have been working out for more than 6 months, the evidence is mixed at best. As for the rest, the clinical studies are all over the map. There’s no convincing evidence that they work.

Whey protein is the best choice for enhancing muscle gain immediately after your workout. Soy and casein are better choices for sustaining muscle gain over the next few hours. If you’re looking at meat protein, chicken is a particularly good choice. Four ounces of chicken will provide the protein and leucine you need to sustain muscle gain for several hours.

Even if you are not working out, recent research on dietary protein and leucine has important implications for your health. In a recent “Health Tips From the Professor” I shared research showing that optimizing protein and leucine intake helps to increase muscle retention and maximize fat loss when you are losing weight.

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.