The effect of BCAA supplementation upon the immune response of triathletes

Introduction: Intense long-duration exercise could lead to immune suppressi on through a decrease in the circulating level of plasma glutamine. The dec rease in plasma glutamine concentration as a consequence of intense long-du ration exercise was reversed, in some cases, by supplementing the dirt of t he athletes with branched-chain amino acids (BCAA). To better address this question, we have evaluated some blood parameters (lymphocyte proliferation , the level of plasma cytokines, plasma glutamine concentration, and in vit ro production of cytokines by peripheral blood lymphocytes) before and afte r the Sao Paulo international Triathlon, as well as the incidence of sympto ms of infections between the groups. Methods: Twelve elite male triathletes of mean age 25.5 +/- 3.2 yr (ranging from 21.4 to 30.1 yr), weighing 74.16 +/- 3.9 kg, swam 1.5 km, cycled 40 km, and ran 10 km (Olympic triathlon) i n the Sao Paulo international Triathlon held in April 1997 and April 1998. in both events, six athletes received BCAA and the others, placebo. Results : Athletes from the BCAA group (BG) presented the same levels of plasma glu tamine, before and after the trial, whereas those from the placebo group sh owed a reduction of 22.8% in plasma glutamine concentration after the compe tition. Changes in the proliferative response of peripheral blood lymphocyt es were accompanied by a reduction in IL-1 production after exercise (22.2% ), which was reversed by BCAA supplementation (20.3%), without changes in I L-2 production. Discussion: The data obtained show that BCAA supplementatio n can reverse the reduction in serum glutamine concentration observed after prolonged intense exercise such as an Olympic triathlon. The decrease in p lasma glutamine concentration is paralleled by an increased incidence of sy mptoms of infections that results in augmented proliferative response of ly mphocytes cultivated in the absence of mitogens. The prevention of the lowe ring of plasma glutamine concentration allows an increased response of lymp hocytes to ConA and LPS, as well as an increased production of IL-1 and 2. TNF-alpha, and IFN-gamma possibly Linked to the lower incidence of symptoms of infection (33.84%) reported by the supplemented athletes.