Effects of fermentable fiber and polyphenol supplementation on mood and cognition in adults during hypobaric hypoxia exposure

This study investigated the effects of fermentable fiber and polyphenol supplementation on mood and cognition following rapid ascent to simulated 4300 m. Healthy adults (n = 13, 21 ± 3 years) participated in a randomized, placebo-controlled crossover study consisting of three, 2-week phases separated by ≥1 week. Food products containing the fiber and polyphenol supplement or placebo were consumed during each phase. During the final 2 days of each phase, participants resided in a hypobaric chamber for 36 h simulating low (500 m) or high (4300 m) altitude, creating three conditions: placebo-500 m, placebo-4300 m, and supplement-4300 m. A computerized cognitive test battery was administered each morning, evening, and ~36 h post-chamber residence to assess mood and cognition. Total mood disturbance, tension, fatigue, and depression were higher, and total risk-propensity score, energy, self-control, and invincibility were lower at 4300 m versus 500 m independent of supplementation. Relative to placebo-500 m, anger was higher during placebo-4300 m, but not supplement-4300 m, whereas confusion was greater during supplement-4300 m but not placebo-4300 m. More vigilance false alarms occurred during 500 m versus 4300 m independent of supplementation. Although short supplementation and washout periods may have limited observable effects, findings do not support favorable effects of this fiber and polyphenol supplement on cognition but suggest the supplement may attenuate hypobaric hypoxia-induced increases in anger.