Fructooligosaccharides

About

What it is and where it shows up.

Fructooligosaccharides (FOS) are short-chain, non-digestible carbohydrates composed of fructose units linked to a sucrose terminal glucose, occurring naturally in plants and breast milk. They are added to functional foods, infant formula, and dietary supplements as prebiotic dietary fibers to selectively stimulate the growth of beneficial gut bacteria such as bifidobacteria.

Safety summary

The regulatory and scientific consensus.

FOS is broadly considered safe with no formal Acceptable Daily Intake (ADI) established; the US FDA has granted GRAS status for use up to 20 g/day in adults and up to 4.2 g/day in infants under one year. High intakes may cause gastrointestinal discomfort including bloating, flatulence, and osmotic diarrhea due to rapid colonic fermentation. Individuals with irritable bowel syndrome (IBS) or FODMAP sensitivity are particularly susceptible to adverse gastrointestinal effects.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
EFSA (European Food Safety Authority) (European Union)	Approved	FOS does not carry a designated E number and is not regulated as a food additive under Regulation (EC) No 1333/2008; it is permitted as a food ingredient and dietary fiber. EFSA's NDA Panel evaluated health claims for FOS under Regulation (EC) No 1924/2006 (EFSA Journal 2011;9(4):2023 and 2016). No formal ADI has been established.source
FSSAI (Food Safety and Standards Authority of India) (India)	Approved	Permitted in infant formula under FSS (Infant Formula) Regulations (Version II, Jan 2024); FOS content must not exceed 0.8 g/100 ml. When combined with galacto-oligosaccharides (GOS), the prescribed ratio is 90:10 (GOS:FOS). Also recognized as a permissible prebiotic under FSS (Health Supplements, Nutraceuticals, Food for Special Dietary Use) Regulations.source
FDA (Food and Drug Administration) (United States)	Approved	GRAS status first established under GRN 44; scFOS permitted up to 20 g/day for the general population and up to 4.2 g/day for infants under one year, excluding use in meat, poultry, and standalone infant formula. Status subsequently reaffirmed across multiple GRAS Notices: GRN 605 (2017), GRN 623, and GRN 1006 (2021).source

Who should approach with care

Whose guidance would steer them away.

Ibs — FOS is a fermentable oligosaccharide (FODMAP) that undergoes rapid colonic fermentation, which may trigger or worsen bloating, gas, cramping, and diarrhea in individuals with irritable bowel syndrome.

Ibd — Rapid colonic fermentation of FOS may exacerbate gastrointestinal symptoms and mucosal irritation during active flares of inflammatory bowel disease.

Infants — FSSAI and FDA both impose strict dose limits for FOS in infant nutrition (≤0.8 g/100 ml per FSSAI; ≤4.2 g/day per FDA GRN 44); excess intake in infants may cause osmotic diarrhea and GI discomfort.

Research citations

The sources behind this verdict.

1FSSAI. Food Safety and Standards (Infant Formula, Follow-up Formula, and Infant Foods) Regulations — Version II, 2024. fssai.gov.in
2FSSAI. Food Safety and Standards (Food for Infant Nutrition) Regulations – Compendium Version II, 2024. fssai.gov.in
3PubMed. Gastrointestinal Tolerance of Short-Chain Fructo-Oligosaccharides from Sugar Beet: An Observational, Connected, Dose-Ranging Study in Healthy Volunteers, 2022. pmc.ncbi.nlm.nih.gov
4PubMed. Fructooligosaccharides: From Breast Milk Components to Potential Supplements. A Systematic Review, 2022. pmc.ncbi.nlm.nih.gov
5FDA. GRAS Notice 1006: Short-chain fructooligosaccharides, 2021. fda.gov
6FDA. GRAS Notice 990 – Short-chain Fructooligosaccharides for Use in Infant Formula, 2021. fda.gov

Independently researched10 citations