Gut Microbiome Support

The gut microbiome influences far more than digestion. Fermentation of fibre produces short-chain fatty acids — principally butyrate, propionate and acetate — that fuel colonocytes, strengthen the intestinal barrier, induce regulatory T cells and modulate systemic inflammation. Butyrate alone supplies most of the energy used by the colonic epithelium. Diversity is the single most consistent marker of a healthy microbiome across studies. Reduced diversity is associated with inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease and depression, though causality runs in both directions and remains partly unresolved. The American Gut Project found that people eating more than thirty different plant species weekly had markedly greater microbial diversity than those eating fewer than ten — a more powerful lever than any supplement currently available. Supplements have a supporting role. Specific probiotic strains have strain-specific evidence for particular endpoints, prebiotic fibres such as inulin, GOS and partially hydrolysed guar gum feed existing beneficial populations, and psyllium supports the barrier while being only lightly fermented. Testing is largely unhelpful outside research: consumer microbiome sequencing cannot yet generate reliable individual recommendations.

{"avoid": "Unnecessary antibiotics, chronic high alcohol intake, and diets built on ultra-processed food", "timeline": "Composition shifts within days of dietary change; stable diversity gains take weeks to months", "foundation": "Eat 30+ distinct plant species weekly and 30-40 g fibre daily", "prebiotics": "Introduce inulin, GOS or partially hydrolysed guar gum gradually from 2-3 g to 5-10 g/day", "polyphenols": "Berries, green tea, cocoa, olive oil and coffee feed beneficial taxa", "fermented_foods": "2-3 servings daily of kefir, live yoghurt, sauerkraut, kimchi or miso — shown in trial to raise diversity and lower inflammatory markers", "resistant_starch": "Cooked and cooled potato, rice, legumes and green banana"}

• •Maximise plant food variety rather than quantity of any one fibre
• •Include fermented foods daily — the Stanford trial showed diversity gains and reduced inflammatory markers
• •Exercise regularly, which independently increases microbial diversity
• •Protect sleep, since circadian disruption alters microbial composition
• •Manage stress, given bidirectional gut-brain axis signalling
• •Avoid unnecessary antibiotics and acid-suppressing drugs where possible
• •Limit alcohol, which reduces diversity and increases permeability
• •Spend time outdoors and with pets, both associated with greater diversity