Distinct modulatory effects of high-fiber and fermented-food diets on gut microbiota, immune function, transit time, and sleep quality in a citizen science randomized controlled trial
Abstract
A randomized, placebo-controlled citizen science-based dietary intervention was conducted among 147 healthy adults to evaluate the effects of 8-week high dietary fiber (HDF) and high fermented food (HFF) diets on gut microbiota, immune function, gut transit time, well-being, and sleep quality. The HDF group significantly increased fiber intake ({Delta}10.3 g/1000 kcal/day) following high dietary fiber recipes with addition of dried chicory root, while the HFF group increased fermented food consumption (+6.3 portions/day), including a fermentation-derived liquid supplement. At the 21-week follow-up, modest improvements in fiber and fermented intake were sustained, compared to baseline. Microbial diversity significantly increased within the HFF and control groups, especially in HFF participants over 50 (p = 0.04). Compared to CG, HFF showed no difference in microbial diversity, whereas the HDF group showed a significant decrease. The HDF intervention enhanced butyrogenic potential by increasing Anaerostipes, Faecalibacterium, and Bifidobacterium spp., and significantly reduced gastrointestinal transit time (p = 0.01). The intake of high fiber improved and sustained sleep quality (p = 0.03). The HFF intervention significantly increased blood immune markers including CD5, CD6 and CD8A (T-cell activation), IL-18R1 (inflammatory signaling) and SIRT2, a longevity-associated deacetylase (Q < 0.05), and induced a modest shift in the gut microbiota of participants over 50 years toward…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 147 participants or records.
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