"Good," or probiotic, bacteria reside in our gastrointestinal tract along with a host of their nasty cousins. It is believed that eating probiotics - foods that contains probiotic bacteria - will help to increase the population of good bacteria and ward-off disease and infection. Probiotics include yogurt, kefir, buttermilk, kim chi, and miso soup.
Bacteria that live in our GI tract use partially digested food to grow. Prebiotics are foods that nourish good bacteria in the intestine and allow them to survive and multiply. Prebiotics include chicory, onions, garlic, artichokes, bananas, and asparagus.
Nutritional supplements comprised of probiotic bacteria and prebiotic sugars. Synbiotics work to both add good bacteria to the GI tract and encourage the growth of the good bacteria already in residence. Synbiotics are not found naturally in foods, but are added to products such as Activia Light yogurt.