"Now that were deep into the cold and flu season its safe to assume that germs are hiding pretty much everywhere  the keypad at the grocery store checkout the handrail on the bus the air around that miserablelooking coworker. Avoiding germs entirely would require something like solitary confinement or a headtotoe application of Purell. As an alternative many people try to do what they can to strengthen their immune systems. Vitamin C is old news and echinacea and other herbs havent really panned out. But theres a livelier option probiotic supplements that supposedly fortify the immune system. Each capsule of Ultimate Flora Advanced Immunity from ReNew Life Formulas Inc. of Clearwater Fla. contains  billion cultures of the yeast Saccharomyces boulardii. Users are instructed to take two capsules a day with a light meal. A bottle of  capsules sold at Whole Foods and many other health food stores costs about . A capsule of Probiotic Immunity from New Chapter Inc. based in Brattleboro Vt. contains  billion each of  different organisms including Streptococcus salivarius subsp. thermophilus and Lactobacillus acidophilus two species of bacteria often found in yogurt. Other ingredients include herbs such as cumin ginger and spinach. Users are instructed to take two capsules each day preferably one in the morning and one in the evening on an empty stomach. You can buy a bottle of  capsules for about  at many health food stores. The claims The website for Ultimate Flora Advanced Immunity says that it provides seasonal immune support and enhances respiratory health and immunity. Put together the statements seem to imply the product improves immunity against seasonal respiratory infections. But senior vice president of marketing Brian Colin says that the company cannot legally claim to prevent or treat any disease including the cold and flu. Instead he says that Ultimate Flora Advanced Immunity can promote overall immune health. The website for Probiotic Immunity says that the product helps promote optimal digestive and immune system function. A brochure provided by the company said that the supplement offers live probiotics for optimal immune health. As with Ultimate Flora Advanced Immunity users are left to themselves to speculate exactly which illnesses their newly optimal immune system might be fighting off. The bottom line It may seem odd but theres no doubt that a capsule full of live yeast or bacteria could help stimulate the immune system and potentially ward off illness says Paul Forsythe a respiratory specialist and assistant professor of medicine at McMaster University in Hamilton Ontario. But as Forsythe noted in an April  issue of the journal Chest most of the research on probiotics has been conducted in mice and the realworld immunity benefits for humans are uncertain. Companies are taking evidence from animal studies and stretching their claims he says. Still Forsythe sees some room for hope that the right probiotic could make the cold and flu season a little less miserable. There is some evidence that certain strains of probiotics can reduce the severity and duration of a cold. A September  Cochrane Review of  studies found weak evidence that probiotics could help prevent the common cold and other upper respiratory infections in infants children and younger adults. And an April  study in the European Journal of Clinical Nutrition found a Lactobacillus probiotic seemed to improve the immune systems response following a flu vaccination. Dr. Sonia Michail a pediatric gastroenterologist at Childrens Hospital Los Angeles says the basic idea behind socalled immunityboosting probiotics makes sense. As she explains the gut is a major front in the immune systems war against pathogens and the immune cells there must respond to the resident bacteria. If helpful bacteria can activate immune cells in the gut the disease fighters will spread throughout the body. But according to Michail studies suggest that for unknown reasons only some people  perhaps as few as  in   could hope to avoid a cold by taking probiotics. And she adds the evidence for even this modest benefit is far from robust. Forsythe says that probiotics are generally safe and might be worth a try if only for the extra peace of mind. He adds that if he were going to try a product hed choose one with only a single strain. One other thing I wouldnt waste my money on anything expensive he says. healthlatimes.com mailtohealthlatimes.com Read more at latimes.comskeptic."