Effect of leucine supplementation on loss of lean body mass during prolonged hypoxic exposure: A double-blind randomized study

Trekkers exposed to prolonged hypobaric hypoxia commonly experience weight loss, especially loss of lean body mass (LBM). Evidence indicates that protein supplementation, specifically leucine, potentially attenuates loss of LBM in a catabolic state. This study investigated if leucine supplementation would prevent the loss of LBM during prolonged hypoxia. 18 trekkers (M=10 and F=8; age: 47.2 ± 11.5; range: 28-70y), completed a 13-day trek in Nepal from Lukla (2180m) to Everest Base Camp (5364m) with a mean altitude of 4140m. Participants consumed a 7.0g leucine supplement or an isocaloric, isonitrogenous placebo twice daily prior to meals. Body composition, body weight, and circumferences of bicep, thigh, and calf were taken pre- and post-trek. The participants from both treatments experienced significant loss of LBM and weight loss after 13 days at altitudes above 2810m (P< 0.05). However, there was no difference in loss of LBM (leucine -1.2 ± 1.6% placebo -2.1 ± 1.5%), body weight (leucine -2.2 ± 1.5%; placebo -2.3 ± 2.0%), or circumferences between the groups. Overall, our results indicate that under the conditions of this study, leucine did not significantly reduce LBM loss during 13 days of altitude-induced hypoxia. This study was funded by Glanbia Nutritionals.