Branched Chain Amino Acids – The Case For Supplementation

Branched Chain Amino Acids (BCAA) have been given a lot of publicity recently as a possible way to boost recovery, performance and size. However, much of the *evidence* for their efficacy comes from the supplement companies who have a vested interest in people buying them given the high price they can charge for them. On Saturday Rachel and I have a big debate about them and, since my friend Pete in Ottawa is waiting my review of them, I figured I’d address both of their concerns with a article.

Branched Chain Amino Acids are the essential amino acids leucine, isoleucine and valine. These three amino acids have aliphatic side-chains that are non-linear. It is estimated that 1/3 of muscle is made up of these amino acids and there is evidence linking them to a variety of processes including protein synthesis. BCAA do not provide energy to the muscles during workouts and as of yet, there is no evidence linking them to any improvements for endurance athlete.

The evidence in favor of BCAA supplementation:

Muscle is 1/3 BCAA. While not evidence per say, the fact that so much of the muscle is made up of BCAA is a good case for consuming more of them. Providing sufficient raw materials for building muscle is a good idea if you want to build muscle because the inverse is true – you will not grow if you do not eat sufficient amounts of protein.

Promoting insulin activity. Insulin is an anabolic hormone because it promotes cell storage and protein synthesis. It also lowers blood cortisol levels; cortisol is released in response to stress in an attempt to liberate sugar from protein. Of all the amino acids, leucine is special because it can promote insulin release in the absence of blood glucose. It is believed that BCAA supplementation will inhibit protein degradation because it increases the release of insulin.

Promoting translation of protein. Translation is the first state of protein synthesis and it is mediated by intercellular insulin and leucine levels. It is believed that BCAA supplementation will promote protein synthesis because it provides the body with leucine with acts as both a trigger for translation and a promoter of insulin release.

My rational for taking BCAA goes something like this – I know that my body enters a catabolic state when I work out. I know that muscle protein is broken down when I’m in this state and therefore my muscles will not grow. The sooner I can rid my body of cortisol, the sooner it will begin to grow again. Insulin decreases cortisol. The first step in protein synthesis is translation which is initiated by leucine and insulin. BCAA supplementation will increase insulin release and initiate protein synthesis. I believe that I will grow more because my body will be less catabolic, more responsive to insulin and have what is needed to initiate the first step of protein synthesis.

I’m not sure if my reasoning holds up in the real world or if I am supplying my body with enough material to advance protein synthesis once the increased levels of insulin and leucine have started translation but I feel comfortable with my understanding of what is going on with this small be key aspect of the puzzle.

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