Achieving a daily threshold of 25 to 35 grams of diverse dietary fibre from whole foods — including soluble beta-glucan from oats, resistant starch from legumes, and mucilage from seeds — fuels anaerobic colonic fermentation.

Commensal bacteria convert these prebiotic substrates into short-chain fatty acids (acetate, propionate, and butyrate). Butyrate serves as the primary energy substrate for colonocytes, fortifying gut barrier tight junctions and reducing systemic low-grade endotoxemia.