BCAAs: an important supplement to take for muscle building or expensive flavored water?
If you’re in a nutrition store like the Vitamin Shoppe or GNC you’ll see packed shelves of containers of BCAAs (branched chain amino acids) touting that it will help you with muscle protein synthesis post-workout. But does the literature actually prove this? Or are supplement companies just taking our money? I recently read an article in the Journal of the International Society of Sports Nutrition looking at just that. So I just thought I’d give a brief synopsis of the paper to save you some reading time J
A little background first…amino acids are the building blocks of protein. There are 20 amino acids, 9 of which are essential amino acids. Three of these EAAs are BCAAs (leucine, isoleucine, and valine). It was thought that BCAAs may have a special way of stimulating muscle protein synthesis (MPS) thus promoting muscle building, or anabolism. This thought was due to a few findings in rat studies. However, MPS is not the same process in humans as it is in rats. So those studies alone do not provide evidence that BCAAs will in fact stimulate MPS in humans.
This paper then went into breaking down known theories of muscle protein synthesis as well as studies recently done on BCAA consumption to determine whether evidence shows that BCAA consumption leads to more MPS or not. Without going into too much “sciency” detail, the paper explains that well-known theories reported in the literature show it is theoretically impossible for consumption of only BCAAs to create an anabolic state. In a post-absorptive state, muscle protein breakdown exceeds muscle protein synthesis, and you need all 9 EAAs, instead of just the 3 EAAs in BCAAs. (This is true even if they do improve efficiency of recycling of EAAs from muscle protein breakdown to muscle protein synthesis because this efficiency would translate into such a small amount that results would be negligible).
As far as recent studies done on the human consumption of BCAAs, no studies have found any evidence showing improvement in MPS. They looked at Louard et al which showed the balance between muscle protein synthesis and breakdown remained negative, meaning that the catabolic state persisted and an anabolic state was not produced with intravenous infusion of BCAAs. Another study by these same authors found the same result in a chronic elevation of BCAAs. In fact, the studies found decreases in MPS after ingestion of BCAAs.
So, in conclusion, unless you’re in the market for expensive flavored water, I would save your money for your rent or mortgage payment and get your amino acids from your protein in food. I’ve included the link from this paper below if you’d like more detail about the science behind this!