Prebiotic foods

Prebiotics feed helpful microbes in your gut. Most are fibers, but not every fiber is a prebiotic.

Updated November 10, 2026

What counts as a prebiotic

Scientists define a prebiotic as something your gut microbes use selectively, in a way that benefits your health. The established ones are inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS), lactulose, some kinds of resistant starch, and human milk oligosaccharides, found in breast milk.

Foods with prebiotics

Chicory root, Jerusalem artichokes, garlic, onions, leeks and bananas have inulin. Cooked beans and lentils, and potatoes that were cooked and cooled, have resistant starch. Most foods have only low levels, though.

Not every fiber is a prebiotic

Most prebiotics are fibers, but not all fibers are prebiotics. To count, a fiber has to be used selectively by your gut microbes, with a health benefit.

Prebiotics and probiotics

Probiotics are live microbes that benefit your health when you get enough of them. Prebiotics are food for the helpful microbes already in your gut.

Too much prebiotic can cause some gas or bloating.

Questions

What are the best prebiotic foods?

Chicory root and Jerusalem artichokes have the most inulin, then garlic, leeks and onions. Cooked and cooled potatoes add resistant starch.

Is all fiber prebiotic?

No. Most prebiotics are fibers, but many fibers aren’t prebiotics.

What’s the difference between prebiotics and probiotics?

Probiotics are live microbes that benefit your health when you get enough of them. Prebiotics feed the helpful microbes already in your gut.

Can prebiotics cause gas?

Yes, too much can cause some gas or bloating. In one study of healthy young adults, up to 10 g a day of inulin was well tolerated.

Sources

General information, not medical advice. If you have a health condition or take medicines, ask your doctor before adding a fiber supplement.