Branched Chain Amino Acids SupplementationBranched Chain Amino Acids (also known as BCAA's) is a term used to refer to three amino acids that are grouped together due their branched chain nature: Leucine, Isoleucine, and Valine. They make about 35% of the amino acid pool of the muscles.
Leucine appears to be an important player in muscle protein synthesis and preventing muscle protein breakdown, while isoleucine appears to be a fairly potent amino acid to induce glucose uptake into cells. The combination of the two potentially aids muscle cell growth. Valine is under-researched relative to the other two, and the role of valine is not ascertained.
The big problem with BCAA's is lack of scientific literature. The most common problem on the research that has been done is that diet is not controlled. BCAA's, similar to glutamine, are contained in food . So when you have research when 1 group of people is having placebo and 1 group having BCAA's, while diet is not controlled, what type of conclusion can we make? None, except that one group wasn't consuming enough BCAA's from high quality proteins. What tends to happen is the group having BCAA's shows numerous benefits that will depend on the study.All it says is if you're deficient in BCAA's, consuming more BCAA's (in this case, by supplementation), will produce the benefits associated with BCAA's, but that's nothing that we didn't already know. The research that needs to be done is to have both groups consuming adequate amounts of protein and BCAA's, while one group getting additional BCAA's from supplementation and the other one a placebo. From what we know so far, the benefits would most likely be irrelevant, however, until we get proper research, we cannot make assumptions. This makes the claims of supplement companies of improved recovery, improved endurance, muscle building, and so on, completely ridiculous. Especially considering that this product is aimed for bodybuilders and strength athletes. The majority of them is already consuming very high amounts of protein and branched chain amino acids.
Despite this, there's a public that might benefit from BCAA supplementation, and that is people that follow a fairly low diet in BCAAs, whether due to a low amount of dietary protein or a preference toward protein sources with a low BCAA content (for example, a vegetarian diet). However, if you are smart enough with your nutrition, you can get away with eating "incomplete"
(what people call plant-base proteins), and still have no consequences in terms of muscle growth. People think they have terrible amino acid scores or that they're missing completely some of the essential amino acids for growth, and that's simply not true most of the time. If you take a look at the incomplete proteins like beans or rice, you will notice that neither one has a terrible score . The problem is that both of them lack a particular amino acid, but that's why we consider beans and rice to be a complementary protein, because when combined together, the combined amino acid score goes up, they complement each other and they both balance out the one that is lower. So it's just a matter of looking at the amino acids of the foods you're eating and combine them correctly so you can the necessary intake for muscle growth.
Back to the supplementation. If you have a diet low in BCAA’s or just overall dietary protein and you don't want to have the trouble of combining different protein sources to have a full amino acid profile, then supplementing with BCAA’s is acceptable, just remember that BCAA's are extremely expensive. And it's actually not because of the leucine (which seems to be the most important one) , but because of isoleucine and valine. That's why some companies have ridiculous ratios like 8-1-1, due leucine being so cheap.
If you do decide to supplement with BCAA's, the reason of supplement will determine the optimal way to consuming it.
If your goal is to increase glucose uptake into cells, the mixture should favor isoleucine or supplementation of pure Isoleucine should be used. The dosage range of isoleucine is 48-72mg/kg (unless you're obese) regardless of whether isoleucine is used in isolation or whether it is gained via a combination of BCAA supplementation and food.
For the purpose of improving muscle protein synthesis (once again, supplementation is not required if sufficient amino acids are being ingested from food, which most likely are if you're consuming a high-protein diet), a dosage range of leucine supplementation should be in the range of 2-10g.
Valine does not have enough evidence to suggest an optimal dose or even a reason for supplementation.
A good overall BCAA supplemental dose can be 10g of leucine and 10g isoleucine, with no valine, or simply 20g of combined BCAAs with a fairly balanced ratio of leucine to isoleucine.
To sum it up, the BCAA's are leucine, isoleucine and valine, three amino acids that have a branching chemical structure. They play an important role stimulating skeletal muscle growth and protein synthesis, however, if one is consuming a high protein diet, most likely their BCAA's intake is already sufficient, and no additional supplementation is needed.