EP-07 Metabolism and Nutrition
Branched Chain Amino Acid Supplementation Drives Metabolomic Shifts Downstream Of Serotonin In Endurance Runners
Peach, Jesse T.; Funk, Dakota; Frothingham, Lizzi; Colleen, McMilin R.; Bothner, Brian; Miles, Mary P. FACSM
Montana State University, Bozeman, MT. (Sponsor: Dr. Mary Miles, FACSM)
Elevated serum serotonin concentrations have been linked to exercise and are postulated to influence central fatigue. Serotonin is synthesized in the brain from tryptophan, which crosses the blood-brain barrier via the LAT1 transporter. Branched chain amino acids (BCAA) also use the LAT1 transporter, and increased BCAA concentrations limit tryptophan transport and serotonin production. The downstream effects of serotonin dysregulation are not well understood and the specific metabolites promoting serotonin induced central fatigue are unknown.
PURPOSE: Determine the effects of BCAA on serotonin production and uncover the downstream metabolomic processes regulated by serotonin in endurance runners.
METHODS: Endurance runners participating in at least five hours of endurance training per week (n = 10) participated in this double-blind, randomized crossover study. VO2max and treadmill pace at 65% VO2max were determined during an initial visit. In two subsequent visits participants received either a drink containing 11 g of BCAA or a flavor matched control in randomized order. Participants then ran on a treadmill at their predetermined moderate intensity pace for one hour. Blood samples were taken before and after exercise and analyzed via LCMS.
RESULTS: A paired t-test indicated that serotonin was lower (p < 0.05) after consumption of BCAA at pre-exercise but not post-exercise. An untargeted analysis of the LCMS data revealed four metabolites linked to BCAA supplementation and serotonin metabolism elevated after exercise in the BCAA compared to placebo condition, including leucine and valine from the BCAA beverage along with the metabolites octopamine and ornithine.
CONCLUSION: BCAA supplementation led to an initial decrease in serotonin in endurance runners relative to placebo supplementation. However, after exercising this variation dissipated. Supplementation of BCAA also increased the metabolites octopamine and ornithine, which can be metabolically regulated by serotonin-dependent mechanisms, are members of pathways modulating energy production and fatigue, and provide viable links between serotonin concentration and central fatigue. Supported by the Kreighbaum Endowment and Montana State University Research Enhancement FundsCopyright © 2021 by the American College of Sports Medicine