Effects Of Fermentable Fiber And Polyphenol Supplementation On Mood And Cognition During Hypobaric Hypoxia Exposure

Gut microbiota-mediated metabolism of various fermentable fibers and polyphenols produces metabolites that may favorably impact mood and cognition. Whether dietary supplementation with fermentable fibers and polyphenols can mitigate decrements in mood and cognition caused by rapid ascent to high altitudes (HA) is unknown. PURPOSE: To determine the effects fermentable fiber and polyphenol supplementation on mood and cognitive performance following rapid ascent to simulated HA. METHODS: Healthy young adults (n = 13, 21 ± 3 yr) participated in a randomized, double-blind, crossover study consisting of three, 2-wk study phases separated by ≥1 wk. Snack bars providing 15-30 g/d fermentable fibers (oligofructose-enriched inulin, galactooligosaccharide, high amylose corn starch) and 1-2 g gallic acid equivalents/d total phenolics from cocoa seed, green tea leaf, cranberry and blueberry (FP) or matched placebo (PL) were consumed daily during each phase. During the final two days of each phase, participants resided in a hypobaric chamber for 36 hr simulating low altitude (LA; 500 m) or HA (4300 m) to create three experimental conditions: PL + LA, PL + HA, and FP + HA. A computerized cognitive test battery was administered each morning and evening during chamber residence and 48 hr post-chamber to assess mood, risk propensity, spatial memory, grammatical reasoning, and vigilance. RESULTS: Total mood disturbance (PL: p < 0.001, FP: p < 0.001), tension (PL: p = 0.001, FP: p = 0.004) and fatigue (PL: p < 0.001, FP: p < 0.001) were higher and energy (PL: p < 0.001, FP: p = 0.01) and self-control (PL: p = 0.01, FP: p = 0.02) were lower at HA versus LA. Depression (p < 0.001) and anger (p = 0.05) were higher and total risk-propensity score was lower (p = 0.02) during HA with PL, but not with FP, versus PL + LA. Confusion was greater (p = 0.04) and invincibility was lower (p = 0.05) during FP + HA versus PL + LA, but not PL + HA. More vigilance false alarms occurred during PL + LA versus FP + HA (p = 0.003), but not PL + HA. Spatial memory and grammatical reasoning were not affected by HA or FP. CONCLUSION: Mood was impacted to a greater extent than cognition following rapid ascent to simulated HA. Findings do not support favorable effects of the FP blend used on cognition but suggest FP may attenuate increases in depression and anger and declines in risk propensity at HA. Supported by DHP JPC-5 and DEVCOM SC. Opinions are those of the authors and do not reflect those of the U.S. Army or DoD.