Ten times as many bacteria as human cells live in your body, according to a 2012 "Scientific American" report. Not all types of bacteria are harmful. Some types, called probiotics, help keep you from getting sick, at least partially due to limiting the spread of harmful bacteria. Some foods contain probiotics naturally and others have added probiotics.
Probiotics versus Prebiotics
You can increase your healthy bacteria levels by consuming either probiotics or prebiotics. Prebiotics are carbohydrates that aren't digestible, which probiotics use as food. Increasing the amount of prebiotics you consume can help you increase the amount of healthy bacteria in your digestive tract. This may help lower your risk for diarrhea, colon cancer, digestive problems, constipation and even the common cold.
You probably already eat some foods that contain probiotics. Check the label of your yogurt to see if it contains live active cultures, which means it contains probiotics. Other foods to increase your probiotic intake include sour cream, kefir, buttermilk, cottage cheese, pickles made with brine instead of vinegar, sauerkraut, kimchi, pickled ginger, wine, microbrew beer, kombucha, shoyu, tamari soy sauce and fermented soybeans called natto, tempeh and miso.
If you aren't a fan of any of the fermented foods that contain probiotics, try eating more of the foods that contain prebiotics. Fermented dairy products like yogurt contain prebiotics as well as probiotics, but any foods that contain the dietary fibers inulin or oligofructose contain prebiotics. These foods include artichokes, bananas, garlic, honey, onions and whole grains, especially whole wheat.
Many products don't contain enough probiotics on their own to benefit health. You need at least 1 billion colony-forming units for beneficial effects, according to University of Kentucky Extension. Yogurts with live active cultures should contain about 100 million colony-forming units per gram. It's best to get your probiotics from foods rather than supplements, since the foods provide a variety of different probiotics as well as vitamins and minerals that aren't found in supplements.
Based in Massachusetts, Jessica Bruso has been writing since 2008. She holds a master of science degree in food policy and applied nutrition and a bachelor of arts degree in international relations, both from Tufts University.