Prebiotics

Also known as prebiotic, GOS, FOS, fructooligosaccharides.

Last reviewed October 9, 2026 · Jump to references

What is Prebiotics?

In plain words

Prebiotics are substances, often types of fiber, that feed helpful microbes in the gut. Your body does not fully digest these fibers, so gut microbes break them down and make substances that can support the gut lining. Researchers study prebiotics for bowel regularity, gut health, and effects on metabolism. Benefits vary by the type of prebiotic, and some can cause gas or bloating.

Technical definition

Prebiotics are substrates selectively utilized by host microorganisms that confer a health benefit; common examples include nondigestible carbohydrates such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS). Rather than acting through a single receptor, these compounds support microbial metabolism and fermentation in the gut, producing metabolites such as short-chain fatty acids that influence intestinal function. Many prebiotics are used as food or supplement ingredients, with regulatory classification varying by ingredient and jurisdiction.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.