What to eat to improve the microbiome?

The microbiome diet emphasizes whole, minimally processed foods that nourish beneficial microbes and support microbial diversity. Dietary choices shape which bacterial species thrive, influence production of short-chain fatty acids (SCFAs) like butyrate, and affect gut barrier integrity, immune signaling, and even mood. Below is an evidence-based overview of food groups that consistently support a resilient gut ecosystem.

Core food groups that benefit the microbiome

Prebiotic-rich fibers: Foods high in fermentable fibers feed resident bacteria and drive SCFA production. Examples include oats, barley, apples (pectin), bananas (inulin), onions, garlic, leeks, asparagus, and Jerusalem artichokes. Gradually increasing fiber intake to the recommended 25–35 g/day helps minimize discomfort while boosting substrate for butyrate-producing taxa.

Ancient grains and whole grains: Quinoa, millet, farro, barley, and steel-cut oats retain bran and resistant starches that function as prebiotic substrates. Barley and oats contain beta-glucans, soluble fibers associated with increased Bifidobacteria and improved metabolic markers.

Legumes: Lentils, chickpeas, and beans supply soluble and insoluble fibers plus polyphenols that favor diverse microbial communities and support SCFA generation. Regular legume consumption is linked to higher microbial richness on stool-based microbiome analyses.

Fermented foods and probiotics: Sauerkraut, kimchi, kefir, yogurt with live cultures, tempeh, and miso deliver live microbes (Lactobacillus, Bifidobacterium and others) that can transiently colonize or modulate resident ecology. Combining fermented foods with prebiotic fibers enhances their beneficial effects.

Fruits, vegetables and polyphenol sources: Berries, leafy greens, cruciferous vegetables, artichokes, and colorful produce supply diverse fibers and polyphenols that select for beneficial microbes. Polyphenol-rich foods (e.g., berries, green tea, dark chocolate in moderation) are metabolized by gut bacteria into bioactive compounds that influence host physiology.

Practical considerations and testing

Diversity matters: Eating a wide variety of plant foods across the week supports microbial diversity more effectively than repetitive menus. Rotate grains, legumes, vegetables, and fermented options to expose the microbiome to different substrates.

Start slowly: Increase fiber and fermented foods gradually to reduce gas or bloating; maintain adequate hydration. For lactose intolerance or dairy avoidance, plant-based fermented products (coconut or almond yogurts with live cultures) can be alternatives.

Monitoring changes: Stool-based microbiome testing can identify low diversity, overgrowth, or gaps in beneficial strains and help guide food-focused strategies. For an introduction to diet-focused guidance, see what to eat to improve your microbiome. For direct test services, information about gut microbiome testing may clarify which dietary adjustments are most relevant to measurable results.

Contextual resources: If acute illness affects tolerance, consult guidance on foods to avoid during a stomach bug. To learn more about clinical signs, review descriptions of symptoms of an unhealthy gut flora and an external summary of common indicators at What are the symptoms of an unhealthy gut flora.

Summary: A microbiome-supporting diet centers on varied plant fibers, fermented foods, whole grains and legumes, with gradual changes and attention to tolerance. These choices provide substrates and live microbes that foster diversity, SCFA production, and improved gut resilience—outcomes that can be tracked and refined through evidence-informed testing and clinical guidance.