According to the National Center for Complementary and Integrative Health, a division of the National Institutes of Health (NIH), probiotics—found in yogurt, and other fermented foods, such as kefir and buttermilk, dietary supplements, and even beauty products—are live microorganisms that are intended to have health benefits, when consumed or applied to the body.Most probiotics contain a variety of microorganisms—for instance, Lactobacillus and Bifidobacterium—with certain yeasts like Sacchar...