Fructooligosaccharides
SweetenersCAS: 308066-66-2
This is what the ingredient is.
Fructooligosaccharides (FOS) are prebiotic fibers that selectively feed beneficial gut bacteria.
Here is why it shows up on the label.
Used as prebiotic fiber and mild sweetener. Added to yogurt, nutrition bars, and supplements.
Here is what food agencies say.
The FDA lists it as Generally Recognized as Safe. recognized as dietary fiber. It is permitted in many countries worldwide.
Here is what research has found.
Strong evidence for prebiotic effects. Supports bifidobacteria growth. May improve mineral absorption.
Here are a few things worth knowing.
May cause gas, bloating, and GI discomfort, especially initially. Start with small amounts.
Sources
- FDA GRAS Notice
- EFSA Scientific Opinion
- Journal of Nutrition
How to read this page
We publish plain facts about this ingredient so a label is easier to read. This is not medical advice, and it is not a recommendation to buy, avoid, or use anything. For a personal health question, talk with a clinician who knows your history.
v1.0Updated 9/12/2026