SUMMARY: This study is an article review of the studies on whether or not consuming BCAAs (branched chain amino acids) alone was enough to promote muscle growth. Muscle protein is constantly being synthesized and broken down (anabolism, catabolism). Amino acids in blood plasma come from absorption of ingested and then digested proteins by the small intestine or are released by muscles when the body is not absorbing food (post-absorption state). During this period, the rate of catabolism outpaces that of anabolism by 30%. When subjects were given intravenous BCAA, muscle protein synthesis dropped compared to the control (who got saline); but these conclusions are only from 2 studies. A lot of other studies looked at the signals of anabolic metabolism, but not at actual muscle protein synthesis. BCAAs only aided in muscle protein synthesis when it was taken as a supplement to a protein meal.
LESSON COMMENTS: This article is easy to read and understand, plus it gives a good explanation of the process of muscle protein synthesis. Teachers should have an easy time understanding the paper and excerpts can be assigned to students. Topics covered in this paper are: connecting the process of protein synthesis with the digestive system and circulatory system, anabolism and catabolism, endothermic and exothermic reactions, oxidation reactions, and limiting reagents and percent yield.
Wolfe R. R. (2017). Branched-chain amino acids and muscle protein synthesis in humans: myth or reality?. Journal of the International Society of Sports Nutrition, 14, 30. doi:10.1186/s12970-017-0184-9