Originally Posted by AEN
Branch chain amino-acids or just Leucine?
In a previous entry of mine, I reviewed a study that compared the muscle protein stimulus of the essential amino acids (EAA) against a branch chain amino acid formula, that contained an equal amount of leucine compared to the EAA supplement. What that study showed, was that BCAAs could only stimulate protein synthesis for a short time(15-30mins) and then declined rapidly, while the EAA supplement kept protein synthesis stimulated for four hours. In a nutshell, this study and other show the presence of the other EAAs are needed to maintain the rate of muscle protein synthesis, stimulated by leucine.
The next study being reviewed looked at muscle protein synthesis(MPS) in rats and compared the rates brought about by various mixtures of amino-acids and glucose. For simplicities sake, we will just focus on the rates of MPS brought about by the leucine and glucose mixture compared to the BCAA and glucose mixture. The outcome showed there was NO difference in MPS between the two groups, with the researchers stating "the effect of the BCAAs can be attributed entirely to leucine, which had the same effect as the 3 BCAAs together, whereas isoleucine and valine had no effect"
The role of leucine in the regulation of protein metabolism
J Nutr. 2005 Jun;135(6 Suppl):1553S-6S.
This is true, also, you need ALL essential amino acids to complete protein synthesis, the amino acid that even starts protein synthesis, methionine, isn't one of the BCAA's but an EAA. You can actually get into a protein negative if you have a large imbalance of certain amino acids within the body.
Well, there is this theory that if you don't take in ALL the EAA's (which include BCAAs) in a 1:1:1:1 etc ratio, that you actually can come up to a overall protein balance negative. Your body can't make EAAs, only the NEAAs, so that leaves nine amino acids you HAVE to ingest for your body uses. To make your skeletal muscle protein (proteins are classified having ALL 20 amino acids + usually over 50 amino acids lengths long) you still need the other EAAs even if you ingest tons of BCAAs. So if you ingested a ton of BCAA, and your body still needs the other EAAs, you still can't complete protein synthesis, and you sit in a overall protein balance negative till you get those in. So what I do is I add additional L-Tryptophan to my EAA ****tail (I think all on the market are missing the EAA L-Tryptophan) so that I am not missing an individual EAA, cause you need it anyway, your body can't make it.
For now I won't recommend anyone take just a BCAA or incomplete EAA product when all the EAA studies were done with ALL the EAAs, not missing L-Tryptophan like all the EAA products out (that I am aware of).
Essential amino acid - Wikipedia, the free encyclopedia
Originally Posted by Wiki
Therefore, a balance of essential amino acids is necessary for a high degree of net protein utilization
Originally Posted by Wiki
The net protein utilization is profoundly affected by the limiting amino acid content (the essential amino acid found in the smallest quantity in the foodstuff), and somewhat affected by salvage of essential amino acids in the body.