Probiotics: beneficial bacteria

Up to 500 species of bacteria call your digestive system home (but that’s no reason to panic). While some of these bacteria can cause disease, others actually help fight it. These “friendly” bacteria also help digest food and produce certain vitamins, like vitamin K. There are times when your body needs more of these beneficial bacteria—when taking antibiotics or having diarrhea, which wipe out the bacteria population, for example. They can be supplied in the form of probiotics. These foods and supplements contain live bacterial cultures, and there’s mounting evidence they can help with gastrointestinal and other health concerns.
Food vs. supplements: Yogurt, which often contains Lactobacillus acidophilus or other live cultures, is the best-known probiotic food, but others include miso, kefir, sauerkraut, and kimchi. I believe these foods can be healthful components of a sound diet, but I generally prefer probiotic supplements, which tend to be much more concentrated sources of friendly bacteria.
Health benefits: I often recommend probiotics for digestive problems. Studies suggest they can help prevent and treat many kinds of diarrhea: antibiotic-related, infectious, and traveler’s. They’ve been shown to benefit people with IBS, ulcerative colitis, or Crohn’s by counteracting “unfriendly” bacteria in the colon. I also suggest probiotics to people with sluggish digestion, excessive gas and bloating, fatigue, and allergies. Women with recurrent yeast infections can help prevent them by taking a probiotic supplement. Probiotics can also help prevent and treat urinary tract infections by acting against “bad” bacteria such as E. coli.
Choosing a product: When shopping for a probiotic supplement, look for ones made withLactobacillus GG. This strain has been well studied, survives passage through the strong acid of the stomach, and actually makes it into the intestinal tract where it’s needed.
Tips for using: I recommend taking probiotic supplements with a meal to buffer stomach acids. To prevent antibiotic-related diarrhea, take a probiotic throughout the course of antibiotic treatment and for a few days afterward. It’s best to take the probiotic and the antibiotic a few hours apart to minimize interference between the two. To avoid traveler’s diarrhea, I start taking a probiotic several days before my departure for a developing country and continue until a few days after my return.
Safety: In general, probiotic supplements seem to be extremely safe, and it’s fine to take them indefinitely—on a daily basis or a few times a week—for chronic health concerns.
Here’s what the mayo clinic has to say about it