A probiotic is a microbial dietary supplement that beneficially affects the intestinal tract. Prebiotics are indigestible food ingredients and what they essentially do is selectively stimulate the growth and/or activity of one or a number of bacteria in the colon. In other words we can say that prebiotics induce change in intestinal flora (bacteria). Commonly, probiotics are used to prepare fermented dairy products such as yogurt and other freeze-dried cultures. Researches are now trying to incorporate probiotics in fermented vegetable and meat products. These dietary supplements can help a lot by immunity enhancement and alleviation of lactose intolerance (intolerance to milk).
Though these studies are yet inadequate, they do suggest that that probiotics could even help in reducing the risk of rotavirus-induced diarrhea, and colon cancer.
Evaluations continue to determine how these can be used as functional food ingredients.