Not all bacteria are unfriendly. Some, like probiotics, are good for us: they coat our digestive tracts and may ward off yeast infections, stomach upsets and allergies.
The University of Michigan's Dr. Gary Huffnagle, author of "The Probiotics Revolution," says most adults don't get enough of them: "Your intestinal environment is shaped by what you eat, and foods high in refined sugar and antibiotics can kill off those good microbes." To help those good bugs flourish, eat probiotic-rich foods like yogurt, kimchi, pickles, miso soup and aged cheese. Or try supplements. For supplement reviews: consumerlabs.com/results/probiotics.asp.