In a recent study, giving school aged children probiotics decreased their chances of getting the flu. Yet another reason to add to the list of how probiotics can help us. The majority of your immune system cells hang out in your gut, and as a Naturopathic Doctor I was taught that many many heath problems can be traced to problems there. If your GI tract is not healthy it is a big drain on your system, and more difficult for you to digest and absorb the nutrition you need. A very important part of the integrity and health of your GI comes from the bacteria which live there, and their populations in both number and variety are easily shifted by our modern lives. Any gastrointestinal illness can disrupt this ecosystem, as can food choices, stress, and of course antibiotics. Traditional cultures had unique cultured foods, which were eaten regularly to replenish this gut ecosystem including sauerkraut, kim chi, and yogurt, to name a few. These are still excellent sources of lactobaccilis, and other bacteria to help keep our guts and therefore our bodies healthy. I recommend eating them regularly, preferably home made versions. If leaving a jar of cabbage out on your counter to ferment doesn't work for you, you are in luck, because thanks to modern technology we can manufacture billions of these guys and put them in a pill. Not all probiotic supplements are the same though. For the freshest, most potent supplements talk to someone like me who can order probiotics shipped on ice from highly respected manufacturers, and even choose a selection of bacteria best suited to your needs. Many grocery store brands, though not as potent, are helpful. In general refrigerated probiotics are likely to be more potent, and check expiration dates for a fresh bottle. For more information on the study click here.