Mood disturbance, but not overall diet quality, is associated with fecal microbiome diversity in free-living adults

ObjectivesTo investigate the gut-brain axis, we explored the relationships among mood disturbance (MD), diet quality (DQ), and fecal microbiota in free-living adults.MethodsA cross-sectional analysis was conducted with data from 75 healthy adults enrolled in two studies. Anthropometrics, 16s rRNA gene sequencing of fecal microbes, DQ as assessed by Healthy Eating Index-2015 (HEI), and MD determined by Profile of Mood States (POMS) were included. Alpha-diversity and DQ differences were explored between low (n = 37) and high MD (n = 38) groups. Spearman correlations were used to investigate relationships between alpha-diversity, DQ, and POMS subscales. Moderation analysis explored the effect of HEI score on the relationship between MD and alpha-diversity.ResultsParticipants were mostly white (67%), 54.5 years old (+/- 11.8), and overweight (28.5 +/- 6.5 kg/m(2)). Shannon and Simpson indices indicate higher alpha-diversity in participants with low MD compared to high MD (p = 0.004 and p = 0.008, respectively). Simpson and Shannon indices were correlated with subscale of anger (rho = -0.303, p = 0.011; rho = -0.265, p = 0.027, respectively)and total MD (rho = -0.404, p = 0.001; rho = -0.357, p = 0.002, respectively). Refined grains were associated with fatigue and tension subscales (rho = 0.428, p < 0.001; rho = 0.302, p = 0.014, respectively). DQ did not significantly moderate the relationship between alpha-diversity and mood disturbance (F(7, 53) = 2.00, p = 0.072, R-2 = 0.209). Shannon index was a significant predictor of MD (b = -4.39, t(53) = -2.55, p = 0.014), but total HEI score and the interaction (Shannon index*HEI score) were not significant.DiscussionGreater bacterial diversity was associated with lower MD, and DQ was associated with various mood state subscales in this sample of adults.

Automated summary

This study examines the gut-brain axis and its connections to mood disturbance, diet quality, and fecal microbiota in free-living adults. The findings suggest that individuals with lower mood disturbance have higher bacterial diversity in their gut, and diet quality is associated with different mood states.