Reference entry
FOS (Fructooligosaccharides)
Plain-English definitions of microbiome research vocabulary — the terms you'll see across articles, testing services, and probiotic claims.
Glossary context
Defined
in the site-wide microbiome glossary
Definition
Short-chain prebiotics found naturally in onions, garlic, bananas, and asparagus. Like inulin, FOS selectively promotes the growth of beneficial bacteria, particularly Bifidobacterium species.
Related terms
Prebiotic
Non-digestible food components (typically dietary fibres) that selectively stimulate the growth or activity of beneficial gut bacteria. Common examples include inulin, FOS, and GOS.
Inulin
A naturally occurring prebiotic fibre found in chicory root, garlic, onions, leeks, and artichokes. It selectively feeds beneficial Bifidobacterium species and is one of the most studied and widely used prebiotic supplements.