What Are Branched Chain Amino Acids

August 9, 2013

Branched Chain Amino Acids can be found in pre-workout supplements and are often recommend to be taken during a workout to decrease fatigue and manage energy levels.
Branched Chain Amino Acids (BCAAs) is a term used to refer to three amino acids that are grouped together due to having branched chains in their structure; these are Leucine, Isoleucine, and Valine.

Of these three amino acids, leucine is important in muscle protein synthesis and for preventing muscle protein breakdown while isoleucine appears to be a fairly potent amino acid that improves cellular glucose uptake; the combination of the leucine and isoleucine aids in muscle cell growth. Valine is under-researched relative to the other two, and its’ role in a BCAA supplement is not fully known.

When a diet is low in BCAAs overall (low dietary protein or vegetarian diet) then BCAA supplementation is able to promote muscle protein synthesis and aid in muscle growth over time. Since this is not reliably seen in those with a protein sufficient diet (1-1.5g/kg or higher) it is likely that dietary protein sources contain sufficient amounts of BCAAs

One use for BCAA supplementation is to manage fatigue, as supplying BCAAs is thought to prevent a serum decline in BCAAs that occurs during exercise which then leads to increased levels of fatigue. However this antifatigue effect may only apply to novice athletes (as studies in trained athletes fail to find a significant anti-fatigue effect).

Overall, aside from the possible anti-fatigue effect BCAAs are highly important compounds to ingest on a daily basis but supplementation is not required if the diet is sufficient in BCAAs. If dietary protein intake is insufficient due to different diets or due to health conditions, BCAA supplements can fill the requirement.


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