It's one of the most familiar sources of probiotics -- "good" bacteria that keep a healthy balance in your gut. Studies suggest that probiotics can help ease lactose intolerance. They also may help tame gas, diarrhea, and other tummy troubles. You can pay extra for brands with certain probiotics, but any that have "live and active cultures" may help.

Choose the unpasteurized kind. The pasteurizing process, which is used to treat most supermarket brands, kills active, good bacteria. Sauerkraut and the similar but spicy Korean dish kimchi are also loaded with immune-boosting vitamins that can help ward off infection.

A popular breakfast food in Japan, this fermented soybean paste can get your system moving. Probiotic-filled miso is often used to make a salty soup that's low in calories and high in B vitamins and protective antioxidants.

They’re good for your digestion, but not all probiotics can survive the journey through your stomach and intestines. Research finds that strains in fermented soft cheeses, like Gouda, are hardy enough to make it.

According to legend, shepherds in the Caucasus Mountains, which divide southeastern Europe from Asia, discovered the milk they carried tended to ferment into a bubbly beverage. Thick, creamy, and tangy like yogurt, kefir has its own strains of probiotic bacteria, plus a few helpful yeast varieties.

The next time you make a sandwich, pay attention to what's holding your cold cuts and cheese. San Francisco's famous sourdough bread packs a prebiotic that may help digestion.

One of the easiest ways to get probiotics is to use this kind of milk, which has been fermented with bacteria. You may see it labeled as sweet acidophilus milk. Buttermilk, too, is rich in probiotics.

When looking to pickles for probiotics, choose naturally fermented kinds, where vinegar wasn't used in the pickling process. A sea salt and water solution feeds the growth of good bacteria, and it may make sour pickles help with your digestion.

Made from a base of fermented soybeans, this Indonesian patty makes a type of natural antibiotic that fights certain bacteria. Tempeh is also high in protein. People often describe its flavor as smoky, nutty, and similar to a mushroom. You can marinate it and use it in meals in place of meat.

Probiotics aren’t only in foods. They also come in capsule, tablet, powder, and liquid forms. Although these supplements don't provide the nutrition that foods can offer, they're easy to use. If you think they might work for you, talk to your doctor first. If you're ill or have immune system problems, you may want to be cautious about taking probiotics.

While probiotic foods have live bacteria, prebiotic foods feed the good bacteria that already live in your gut. You can find prebiotics in things like asparagus, Jerusalem artichokes, bananas, oatmeal, red wine, honey, maple syrup, and legumes. Try prebiotic foods on their own, or pair them with probiotic foods to add a boost.