Fructooligosaccharide (FOS) is a short-chain prebiotic fiber. Onions, bananas, and chicory root contain it naturally. Your small intestine cannot break it down, so it passes whole into the colon. There it feeds helpful bacteria, especially Bifidobacteria strains.
Many people take FOS to support digestion and keep bowel movements regular. Feeding good gut bacteria helps steer the microbiome toward balance. Its fermentation happens more gently than with some other prebiotics, so it often produces less gas.
Mix the powder into water, juice, or soft food once a day. Begin with a small dose and inch upward over a week or two. That slow start cuts down on early stomach upset.
Gas, bloating, and belly cramps can show up at first, particularly with bigger doses. Anyone with irritable bowel syndrome should go slow and watch for reactions.