Do Branched-Chain Amino Acids Help You Build Muscle? by Jerry Brainum 8/21

 

While it's no secret that you need to ingest protein to help develop larger muscles, what is really needed are the elemental building blocks of protein known as amino acids. The body uses 22 of these amino acids, but only nine are deemed essential. What that means is that these particular amino acids cannot be synthesized in the body, but must be ingested from food sources. The other amino acids are called "non-essential" because they can be synthesized in the body from other amino acids. In terms of building muscle, only the nine essential amino acids are required and they must all be present at the same time for the full expression of muscle protein synthesis (MPS), the cornerstone of muscular hypertrophy or growth. Some amino acids are termed "conditionally essential" because the body cannot produce them in sufficient amounts under certain conditions, such as high stress. Examples include arginine, glutamine, and taurine. But from a bodybuilding perspective, the most controversial and popular amino acids are easily the branched-chain amino acids (BCAA).

The BCAA consist of three essential amino acids: leucine, isoleucine, and valine. They are often termed "muscle amino acids" because unlike other amino acids, the metabolism of the BCAA largely occurs in muscle. Indeed, 35% of the amino acids found in muscle are BCAA.  Of all the essential amino acids (EAA) the BCAA are the ones most involved in muscle building and maintenance. One of the BCAA, leucine, is considered the primary "trigger" for initiating MPS. It does that by blunting the activity of a substance that blocks the activation of the Mammalian Target of Rapamycin or mTOR. The significance of mTOR is that it plays a pivotal role in kick-starting the entire anabolic sequence of events that results in increased muscular hypertrophy. And since BCAA are intimately involved with mTOR activation, especially leucine, it's not hard to understand why BCAA is so valued by bodybuilders and athletes.

But there are also many controversies involved with BCAA. The main one is whether there is any need to ingest separate BCAA supplements since most high-quality protein foods are rich in BCAA content. Whey protein alone contains 16% BCAA, which makes ingesting a separate BCAA supplement with whey tantamount to selling sand to Saudi Arabia. Just one chicken leg provides 5,160 milligrams of leucine, which is more than is found in typical BCAA food supplements and at a fraction of the cost. But the research about BCAA in relation to training and muscle gains is paradoxical, with some studies showing definite benefits from extra BCAA supplements, and others suggesting that the supplements are just a waste of money.

One study initially appeared to offer proof that BCAA does offer definite muscle-building effects. This study featured 10 trained young men, average age, 20, who ingested either 5.6 grams of BCAA or placebo following a weight workout. The results of the study showed . . .