Prebiotics

Prebiotics are food ingredients that induce the growth or activity of beneficial microorganisms (e.g., bacteria and fungi). The most common example is in the gastrointestinal tract, where prebiotics can alter the composition of organisms in the gut microbiome.

In diet, prebiotics are typically non-digestible fiber compounds that pass undigested through the upper part of the gastrointestinal tract and stimulate the growth or activity of advantageous bacteria that colonize the large bowel by acting as substrate for them. They were first identified and named by Marcel Roberfroid in 1995. As a functional food component, prebiotics, like probiotics, are conceptually intermediate between foods and drugs. Depending on the jurisdiction, they typically receive an intermediate level of regulatory scrutiny, in particular of the health claims made concerning them.

According to one source, "a prebiotic is a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health", possibly involving only two classes of prebiotic compounds: trans-galactooligosaccharide and inulin.

Other dietary fibers also fit the definition of prebiotics, such as resistant starch,pectin,beta-glucans, and xylooligosaccharides. A 2016 review stated that prebiotics are: "food ingredients that help support growth of probiotic bacteria" or "nondigestible substances that act as food for the gut microbiota. Essentially, prebiotics stimulate growth or activity of certain healthy bacteria that live in your body."

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