Written by James Grage
If you were to ask your average gym enthusiast to name one of the most popular categories of supplements, undoubtedly many would say BCAA’s, or the Branched Chain Amino Acids Leucine, Valine and Isoleucine - and they would be right. According to a recent study by Industry Research Biz, last year’s global sales of BCAAs exceeded $250 million, and is expected to grow to more than $330 million over the next 5 years.
BCAAs have been around for a long time but they really started to gain popularity in 2009 after some studies suggested that BCAA’s could help build lean muscle mass, increase strength, reduce protein breakdown and maybe even reduce body fat. In light of that information, you would have been crazy not to take BCAAs. For me personally, I knew some of the researchers that first published these studies on BCAAs, so of course I was quick to support them and early on I was an advocate for the benefits of BCAA supplementation. At that same time I was one of the founders of a very large Sports Nutrition company which was among the first to market a BCAA product. It turned out to be a massively popular product for us, as well as for several other big brands, so of course other brands quickly followed suit. Fast forward to today and try finding a Sports Supplement company that doesn’t have a BCAA product in their lineup. It makes sense though, if a product really works and has great science to support it, then of course it’s going to have longevity...BUT that begs the question: Now, more than a decade later, does the science still support some of these original claims of BCAA supplementation?
So let’s talk about some of the science that makes BCAAs appealing. For starters, one-third of our skeletal muscle protein is made up of BCAA’s, so it seems logical to think that by consuming more BCAAs it might result in more muscle. This is partially true. Throughout the day our body is in a constant state of muscle protein breakdown versus muscle protein synthesis (MPS). If we are looking to build muscle then the rate at which muscle protein synthesis occurs must outpace muscle protein breakdown and we are literally trying to “build up” more proteins in the muscle. This is the point where BCAAs come in. In older research it was suggested that BCAAs, and in particular the amino acid Leucine, are a trigger for stimulating muscle protein synthesis. Now current research supports the fact that Leucine can and does act as a trigger if you will, for turning on muscle protein synthesis.
Now here’s a very important distinction that needs to be made. There is a difference between triggering muscle protein synthesis, or flipping the on-switch, versus sustained muscle protein synthesis resulting in muscle anabolism (building muscle). Think of turning on a battery powered light. The switch may turn the light on, but how long the light stays on is going to be limited by the amount of energy stored in the battery. Maybe an obscure example, but it’s a similar concept with muscle protein synthesis. In order for Muscle Protein Synthesis to actually occur (and be sustained) all of the Essential Amino Acids need to be present. If any one of those essential amino acids are not present - protein synthesis does not occur. Now, quick side note, technically all 20 amino acids need to be present for MPS to occur, but our body is able to synthesize all of the non-essential amino acids, leaving only the EAAs as a dietary requirement. So, to recap, BCAAs, or in particular Leucine, may stimulate muscle protein synthesis but the presence of all of the Essential Amino Acids (EAAs) are going to determine the rate of protein synthesis.
So, what’s the verdict? Can BCAAs help with Muscle Protein Synthesis? Yes, on one condition: All of the other EAAs must be present. To do this you’re going to have to take the BCAAs with either a protein (food or supplement) or an EAA (Essential Amino Acid) supplement, which contains all 9 essential amino acids (including the 3 BCAAs). Now this leads to the question, why take BCAAs by themselves if you can take an EAA supplement and get everything you need for Muscle Protein Synthesis and muscle anabolism?
Now there are other purported benefits of BCAA supplementation including reducing fatigue, replenishment of glycogen stores post-workout and potentially minimizing net protein breakdown during aerobic exercise, but that’s all for another article. In the meantime, is it worth taking BCAA supplements? Well, that’s for each individual to evaluate on their own. There’s certainly no harm in taking them, and if you’re combining them with proper protein or EAA intake then it’s possible that there’s an added benefit. There’s been studies done with subjects taking 5 grams of BCAA with 6.25grams of whey protein which resulted in similar muscle protein synthesis as 25 grams of whey protein. Does that mean that 5 grams of BCAAs taken with 25 grams of whey protein will yield 4 x’s the protein synthesis? Unfortunately no. Research proposes that muscle protein synthesis may be maximized at 25 grams of protein, furthermore only 3-4 grams of leucine is needed to maximally stimulate MPS. Considering that 25% of a quality protein is BCAAs, that would yield more than 6 grams of BCAAs and 3 grams of Leucine. Takeaway? Get at least 25grams of high quality complete protein and you’re probably getting all the BCAAs you need to maximally stimulate MPS.
In a future article we can dive into more information on how BCAAs may serve a role in helping prevent muscle breakdown during strenuous exercise, as well as potentially supporting muscle protein synthesis between meals. Till next time.