BCAA's
Research Summary: BCAA's ability to prevent immunosuppression in endurance athletes has been fairly consistent. However, the data indicating BCAA's ability to prevent muscle catabolism in non-acute trials is scarce. The following study showed positive results that I'd like to see replicated: Mourier and colleagues ecamined the effect of BCAA on the body composition and exercise performance in 25 elite wrestlers. The 19 day study compared 3 hypocaloric diets: a high protein, low protein and high BCAA diet. The latter diet was superior to the others for weight and fat loss. Contrary to what their basic physiological role might lead us to assume, BCAA has failed at showing benefit as an exercise performance enhancer across various treatment protocols (oral, infusion, with/without carbohydrate). In a recent 10 week trial, Kerksick's team observed a whey/casein blend to be superior over BCAA/whey/glutamine mix for improving strength and body composition. This trial needed better control of energy balance, but it still points to the possibility of isolated BCAA receiving undue hype. Additional BCAA supplementation on top of a pre-existing high protein intake is likely unnecessary, since many common foods (dairy, meats, even peanuts) and animal-derived protein supplements already contain a high concentration of BCAA (whey contains roughly 25% BCAA).
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Glutamine
Research Summary: Glutamine may also play a role in improving immune response and promoting glycogen storage. However, these possibilities have been challenged recently by studies demonstrating that glatamine was not the link to immune response, nor did it promote muscle glycogen storage better than wheat hydrolysate or whey hydrolysate. Glutamine does not appear to be effective for muscle or strength gain in healthy subjects beyond placebo under eucaloric or hypercaloric donditions. Rosene and colleagues observed glutamine's ability to maintain nitrogen balance under hypocaloric conditions. However, these results were not replicated in a more recent well controlled trial by Finn's team, where high-dose glutamine (0.35/kg) was ineffective at preserving lean mass during hypocaloric conditions.
