The real deal or expensive pee?
Branched chain amino acids, commonly known as BCAAs, are a really popular supplement and one that we're asked about a lot at The Fit Clinic. They come in tablets, powder and even fizzy drinks in every flavour under the sun. It seems like everyone recommends them. But are they actually any use?
BCAAs are a group of three essential amino acids - Leucine, isoleucine and valine. Amino acids are the building blocks of protein. Leucine is a particularly important amino acid as it acts as a trigger to initiate muscle protein synthesis (MPS) ie. The process which results in muscle building tissue. Research has shown that 2.5g of leucine is required to maximally stimulate MPS. The idea behind taking BCAAs is that they activate MPS, while preventing muscle protein breakdown, even when you’re training, going about your day and not eating. Sounds pretty magical right? Who doesn’t want to build more muscle?
The issue is that all high quality protein sources such as meat, fish, eggs, poultry, dairy and whey protein already contain BCAAs in high enough quantities to stimulate MPS. A good rule of thumb is to aim for 25g of high quality protein per meal to guarantee your 2.5 of leucine and maximal muscle protein synthesis. The main benefit of choosing wholefood protein sources over BCAA supplements is that they also contain all the other amino acids needed to build muscle, which BCAAs do not. Food based protein sources also contain many other important vitamins and minerals such as iron, calcium and zinc to name a few - Again BCAAs fall down in this department as they don’t have much other nutritional value than providing small amounts of protein.
The final issue with BCAAs is that they’re really expensive!
So what does the research say? A lot of research has been conducted into BCAA supplementation and their effects on MPS. BCAA supplementation has been shown to increase MPS to similar effects as other protein sources such as whey protein. However, when MPS was watched over the hours following either BCAA or whey protein supplementation, MPS following BCAA ingestion declined rapidly whereas MPS from whey protein was still elevated up to 5 hours post consumption. The results suggest that whey is the whey to go!
So, is there a situation where they might be useful? In the vast majority of cases, BCAA supplementation isn’t going to have any real benefit. One situation where they might be useful is in a vegan diet. Plant based sources of protein are known to contain lower amounts of essential amino acids, especially leucine. As already discussed, leucine acts as a light switch for turning on MPS. Plant b