In this review, Luke, Owner and Head Personal Trainer of Shift to Strength, expresses the company’s current position on BCAA, or Branch Chain Amino Acid supplementation. The supplement will be critically reviewed to help answer the following questions:
What are BCAAs, how are they different from other amino acids, and what is their role in skeletal muscle repair?
Are they worth supplementing?
Who should be taking them?
It is the Position of Shift to Strength that Branch Chain Amino Acid (BCAA) supplementation, in the vast majority of cases, is not necessary to supplement for optimal results. Instead, the total amount of high-quality protein sources consumed should be emphasized. This is because consuming a high protein diet of ~1.6g/kg/day offsets the need to consume BCAAs as essential amino acid profiles become proficient at this point to maximize results (1,2,3).
What are BCAAs, how are they different from other amino acids and what is their role in skeletal muscle repair?
BCAAs are three amino acids that, along with the other six Essential Amino Acids, or EAAs, are not created by the body and, therefore, must be consumed by dietary or supplemental means.
This is in contrast to non-essential amino acids, which the body can create internally. Both essential and non-essential amino acids make up the protein macronutrient in varying degrees, depending on the specific source. For example, a “complete” protein includes all essential amino acids, including BCAAs:
All animal proteins: meat, poultry, fish, eggs and dairy
In contrast, an “incomplete” source of protein does not include all essential amino acids and, therefore, it becomes more important to combine different sources to meet your body’s protein needs:
Why is this important in the context of BCAA supplementation? Recall that branch chain amino acids are three specific essential amino acids found in varying degrees in the above foods. The question is if they are already found in whole foods, why supplement them?
Branch chain amino acids have been studied since the 1980’s when it was first observed that three specific amino acids, leucine, isoleucine and valine, were found to break down in skeletal muscle as opposed to the liver with the other essential amino acids (2). This led researchers to hypothesize that the branch chain amino acids play a predominant role in muscle growth and repair.
Since then, multiple lines of evidence support that when BCAAs are supplemented in a diet, they outperform controls (2,3). More specifically, it appears that leucine is the most important amino acid for muscle growth and repair. Several studies have shown that adding leucine to a protein led to greater muscle growth and repair than without (1,2,3,4,5,6).
Are they worth supplementing?
At first glance, it may seem like supplementing BCAAs is well worth it. The current literature supports the notion that branch-chain amino acids play a significant role in muscle growth, so why not supplement them to maximize muscle growth and recovery?
It’s the company’s position that although it is true that BCAAs are the prime amino acids responsible for muscle growth and repair, when protein content is consistently held between groups, the benefits of BCAAs disappear; therefore, BCAA supplementation is not required when a high-protein diet is consumed (1,5,6). The company makes this position stand based on the following evidence.
Firstly, most studies looking at the effectiveness of BCAAs compare the supplement to a placebo. In these studies, the investigations aimed to see the isolated effects the supplement had on the body. A better real-world analysis of the supplement’s effectiveness would be to compare BCAAs directly to protein powder, a similar protein source or control for protein in the diet. Churchward-Venne and colleges did just that.
In their study, 40 participants consumed varying degrees of BCAA with protein powder before a workout. Specifically, the group who consumed 6.5g of protein and BCAA had the same increase in muscle repair vs. 25g of whey protein powder.
This study illustrates that a traditional protein powder performs similarly to BCAAs; therefore, no additional benefits are derived from BCAAs (3). This is the first of three studies in this review to demonstrate that the total amount of protein consumed is more important than supplementing BCAAs.
The second study comes from an applied nutritional investigation comparing a high-protein diet to one that relied on BCAA supplementation to maintain skeletal muscle in patients with gastrointestinal cancer. This cross-sectional study compared two diets, a low-protein diet supplemented with BCAA and a high-protein diet with no supplementation, with an effort to preserve lean mass.
The results of this study indicate that total protein consumption is superior to conserving lean body muscle mass lost than supplementing with isolated BCAAs (6). What can be inferred from this study is that a net positive protein balance (the process that muscle growth exceeds muscle breakdown) derived from a high protein diet is fundamentally essential to the maintenance of muscle and overshadows the effects of BCAAs when this nutrition status is achieved (1,2,3,4,5,6).
The final study in the journal of sports medicine and physical fitness is unique because it not only compared BCAA supplementation to non-supplementation in subjects but also monitored the dietary whole BCAA sources found in whole foods. The results indicate that subjects were already consuming the recommended dietary intake of branch-chain amino acids through dietary analysis, with the recommended amount accounting for 0.64g/kg/day.
For context, a 70 kg (154 lbs) male would need ~45g of BCAA, which, if we recall, is found in any complete protein source in large quantities, as well as some incomplete protein sources.
Who should be taking them?
Like most topics, there is often a for and against argument, and both sides must be critically analyzed to get the whole picture. In the case of BCAA supplementation, proponents of the supplement state the enhanced recovery post-exercise versus controls.
Although this is correct mainly on the acute hormonal level, the real question is, to what extent do these findings have real-world applicability to the general population? There are only very few circumstances when BCAA supplementation would be advised in addition to a high-quality diet:
The individual is in an aggressive calorie deficit of ~1000 kcal and needs additional amino acid supplementation due to the lack of calories.
The individual is vegan and could benefit from BCAAs to meet the full spectrum of their amino acid profiles.
The individual is elderly and frail, and additional measures to preserve lean mass and recovery from resistance strength training may be required.
In summary, a critical, unbiased review in conjunction with real-world applicability to the general population has led Shift to Strength to not recommend Branch Chain Amino Acid (BCAA) supplementation in the vast majority of cases. Instead, emphasizing high-quality and complete protein sources should be the de-facto option for most individuals looking to maximize their results.
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Coombes, J. S., & McNaughton, L. S. (2000). Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. Journal of sports medicine and physical fitness, 40(3), 240.
Negro, M., Giardina, S., Marzani, B., & Marzatico, F. (2008). Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system: Journal of Sports Medicine and Physical Fitness, 48(3), 347.
Churchward-Venne TA, Breen L, Di Donato DM, Hector AJ, Mitchell CJ, Moore DR, Stellingwerff T, Breuille D, Offord EA, Baker SK, Phillips SM. Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial. Am J Clin Nutr. 2014;99(2):276–86. https://doi.org/10.3945/ajcn.113.068775.
Reidy PT, Rasmussen BB. Role of ingested amino acids and protein in promoting resistance exercise-induced muscle protein anabolism. Journal of nutrition. 2016;146:155–183. American Society for Nutrition. https://doi. org/10.3945/jn.114.203208.
Hamarsland, H., Nordengen, A. L., Nyvik Aas, S., Holte, K., Garthe, I., Paulsen, G., ... & Raastad, T. (2017). Native whey protein with high levels of leucine results in similar post-exercise muscular anabolic responses as regular whey protein: a randomized controlled trial. Journal of the International Society of Sports Nutrition, 14(1), 43.
Soares, J. D., Siqueira, J. M., Oliveira, I. C., Laviano, A., & Pimentel, G. D. (2020). A high-protein diet, not isolated BCAA, is associated with skeletal muscle mass index in patients with gastrointestinal cancer. Nutrition, 72, 110698.