Does the consumption of branched chain amino acid supplements positively affect lean body mass or attenuate muscle breakdown in athletes who participate in strength or cardiovascular training?
Branched chain amino acids (BCAA’s) have gained much traction as an ergogenic aid amongst athletes and fitness enthusiast alike for both the anecdotal benefits as well as for the research surrounding its supplementation and efficacy. BCAA’s which consist of three essential amino acids, Leucine, Isoleucine and Valine, have been marketed by varying supplement companies as an anabolic product which can drive muscle protein synthesis levels via oral administration, thus producing anabolic responses on their own (Wolfe, 2017). Claims surrounding this classification of supplement also stem from its ability to attenuate muscle loss during periods of caloric restriction or carbohydrate deprivation amongst strength training athletes (Smith-Ryan & Antonio, 2013).
Concurrent claims have also stated that the consumption of BCAA’s coupled with resistance training and caloric restriction will also yield decreases in fat mass while simultaneously preserving lean body tissue (Jackman, Witward, Philp, Wallis, Baar, & Tipton, 2017). Consumption of protein provides our bodies with amino acids which function as the building blocks for skeletal muscle tissue, thus it is a plausible notion that consuming individual amino acid mixtures in sufficient quantities may elicit ergogenic effects beyond consumption of protein containing foods or supplements alone (Wolfe, 2017). Both aerobic endurance training and anaerobic resistance training at intense levels, can induce a negative net protein balance thus furthering validating the consumption of BCAA’s supplements around intense workout times as a means of shifting the body towards a positive nitrogen balance. While there exists a great deal of research supporting these claims there is an equal amount of research refuting the benefits of BCAA supplementation.
So what does the Literature Say?
A great deal of research is centered on the efficacy of supplementing with branched chain amino acids in an attempt to offset the deleterious effects of caloric restrictions while simultaneously aiming to improve fitness and performance levels, endeavors which are often combined simultaneously by athletes (Dudgeon, Kelley, & Scheett, 2016).
Essential amino acids which include the three branched chain amino acids leucine, isoleucine and valine, are the primary drivers for modulating protein balance and play unique roles in protein synthesis and metabolism, insulin and blood glucose regulation and even neural function (Smith-Ryan & Antonio, 2013). Orally ingested branched chain amino acids rapidly appear in the blood stream following consumption, making them exceptional regulators of muscle protein synthesis (Smith-Ryan & Antonio, 2013). Of the three branched chain amino acids, only leucine was found to be able to stimulate muscle protein synthesis levels independent of isoleucine and valine (Smith-Ryan & Antonio, 2013; Jackman et al., 2017). Despite this fact, consumption of only leucine is not recommended as it will lead to elevations in plasma concentration which oxidizes and decreases plasma concentration levels of the other two BCAA’s, isoleucine and valine (Wolfe, 2017).
Whole body protein synthesis is measured in direct response to protein consumed and the anabolic response is further equated with muscle anabolism (Deutz & Wolfe, 2012). The measurement of both protein synthesis and breakdown is an essential component to determining the magnitude of the anabolic response (Deutz & Wolfe, 2012). As muscle protein synthesis levels surpass catabolism the body ends up in an anabolic state, which if supported by additional protein which supply amino acids, will further drive overall net anabolism via attenuation of catabolism, as opposed to further stimulating protein synthesis (Deutz & Wolfe, 2012). Physiologically, the driving factor behind anabolic responses is the influx of amino acids in the post-absorptive state which exceeds transamination of those amino acids or oxidation rates (Deutz & Wolfe, 2012).
Claims made by researchers as to whether or not branched chain amino acids stimulate muscle protein synthesis are made based off of observations made regarding increased anabolic signaling and activation of regulators in protein synthesis (Wolfe, 2017). According to research conducted in the Journals of the International Society of Sports Nutrition, increased muscle protein synthesis via activation of anabolic signaling pathways are rate limited by the available amount of essential amino acids present, needed to provide the necessary precursors for complete proteins (Wolfe, 2017).
Evidenced Based Recommendations
Post exercise, the duration of muscle protein synthesis is limited by both the signal of the BCAA/EAA leucine, but more importantly the availability of the substrates of the 9 other essential amino acids (Smith-Ryan & Antonio, 2013). Based off of these findings, I believe that the consumption of BCAA’s can benefit individuals participating in high intensity exercise. Each of the studies utilized a different BCAA dose within their method protocols ranging anywhere from 5g to a total of 28g consumed either intra or post training. In order to maximize net anabolism, additional protein should be consumed throughout the day and/or combination of a BCAA/EAA supplement either intra and/or post workout to maximize muscle protein synthesis levels and outpace muscle catabolism. These recommendations are very similar to those I observe in my own practices in which I consume 10g of a BCAA/EAA mixture intra workout, followed by whey/casein mixture post workout providing me with varying amino acid profiles post workout. Additionally, I aim to consume 10-20g mixed in solution to be sipped on over the course of the day with meals and in between meals.
Summary
In conclusion, branched chain amino acids can provide a beneficial aspect to muscle anabolism. Based off of research findings, when taken in consumption with complete proteins and other essential amino acids, BCAA’s will have the strongest effect. EAA’s exist as the rate limiting factor to BCAA consumption in regards to supporting increased muscle protein synthesis rates. Additionally consumption of leucine alone is contraindicated despite its ability to directly stimulate muscle protein synthesis as consumption of this singular amino acid will lead to reduced plasma concentrations of the remaining BCAA’s isoleucine and valine.
Disclaimer
All programs and articles provided are intellectual property of James Shmagranoff. No copies or redistribution of these is allowed without express permission from James Shmagranoff. James Shmagranoff is not a doctor and nothing contained within this article is to be taken as medical advice. Always follow the directions of your medical practitioner.
Sources
Deutz, N.E.P. & Wolfe, R.R. (2012). Is there a maximal anabolic response to protein intake with a meal? Clinical Nutrition, 32(2), 309-313. doi:10.1016/j.clnu.2012.11.018
Dieter, B.P., Schoenfeld, B.J, & Aragon, A.A. (2016). The data do not seem to support a benefit to BCAA supplementation during periods of caloric restriction. Journal of the International Society of Sports Nutrition, 13(21), 1-5. doi: 10.1186/s12970-016-0128-9
Dudgeon, W.D., Kelley, E.P., & Scheett, T.P. (2016). In a single-blind, matched group design: Branched-chain amino acid supplementation and resistance training maintains lean body mass during a caloric restricted diet. Journal of the International Society of Sports Nutrition, 13(1), 1-10. doi:10.1186/s12970-015-0112-9
Smith-Ryan, A.E. & Antonio, J. (2013). Chapter 2: Optimizing protein consumption for body composition. Sports nutrition: Performance enhancing supplements (32-34). Ronkonkoma, NY: Linus Learning
Wolfe, R.R. (2017). Branched-chain amino acids and muscle protein synthesis in humans: Myth or reality? Journal of the International Society of Sports Nutrition, 14(30), 1-7. doi:10.1186/s12970-017-0184-9
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