Gut-microbiota-targeted diets modulate human immune status

Diet modulates the gut microbiome, which in turn can impact the immune system. Here, we determined how two microbiota-targeted dietary interventions, plant-based fiber and fermented foods, influence the human microbiome and immune system in healthy adults. Using a 17-week randomized, prospective study (n = 18/arm) combined with -omics measurements of microbiome and host, including extensive immune profiling, we found diet-specific effects. The high-fiber diet increased microbiome-encoded glycan-degrading carbohydrate active enzymes (CAZymes) despite stable microbial community diversity. Although cytokine response score (primary outcome) was unchanged, three distinct immunological trajectories in high-fiber consumers corresponded to baselinemicrobiota diversity. Alternatively, the high-fermented-food diet steadily increased microbiota diversity and decreased inflammatory markers. The data highlight how coupling dietary interventions to deep and longitudinal immune and microbiome profiling can provide individualized and populationwide insight. Fermented foods may be valuable in countering the decreased microbiome diversity and increased inflammation pervasive in industrialized society.

Automated summary

This study investigated the effects of plant-based fiber and fermented foods on the human microbiome and immune system, finding that a high-fiber diet increased glycan-degrading carbohydrate active enzymes while a high-fermented-food diet increased microbiome diversity and decreased inflammatory markers. The data suggest that coupling dietary interventions with immune and microbiome profiling can provide personalized and populationwide insights, with fermented foods potentially valuable in countering decreased microbiome diversity and increased inflammation in industrialized societies.