Functional food or medicinal food is any fresh or processed food that provides a health-promoting and/or disease-preventing property beyond the basic nutritional function of supplying nutrients.
In general, functional foods are either inherently functional or enhanced with health-promoting ingredients like "omega-3-enriched" products. Fermented foods with live cultures are often also considered to be functional foods with probiotic benefits.
The term was first used in Japan in the 1980s, where there is a government approval process for functional foods, called Foods for Specified Health Use (FOSHU).