The study found that mice that were given four to nine weeks of a course of probiotics had a significant increase in bacteria that produce butyrate, a short chain fatty acid that in turn stimulates the release of an appetite-suppressing hormone, glucagon-like peptide (GLP-1) from cells lining the intestine, said Sushil Rane, PhD, one of the study’s lead researchers. This reduced their risk for obesity in a number of ways, Dr. Rane said. The mice ate less food, gained less weight, had smaller fat cells and less fat stored on their bodies, lower blood sugar levels and improved insulin tolerance, compared to the mice that did not get probiotics. They also produced fewer inflammatory biochemicals, called cytokines, that can promote obesity-related illness. “All in all, just about all the ….things measured were beneficial for the mice getting the probiotic,” Dr. Rane said. Benefits were seen both in mice who were bred to be genetically obese (leptin-deficient) and in normal mice made obese by a high-fat diet.  Of course, people often don’t react the same as mice, so until similar studies are done in humans, there is no way to say whether they will have the same benefits, Dr. Rane said. Still, probiotics are generally considered safe and are helpful for other conditions, such as antibiotic-induced diarrhea. If you’re interested in trying this for yourself, he suggests discussing the study with your doctor and deciding together if a course of probiotics it is worth a try.   The probiotic used in the study, VSL#3, is available over-the-counter and by prescription as an FDA-approved drug. A normal dose (one packet) contains 450 billion live, freeze-dried bacteria, a mix of eight strains: Bifidobacterium breve, B. longum, B. infantis, Lactobacullus acidophilus, L. plantarum, L. parcasasei, L. bulgaricus, and Streptococcus thermophiles. (It is also available in double strength.)  Researchers also tested eight other probioitcs before settling on VSL#3. “I’m not saying the others didn’t work, but we found VSL#3 was the most effective and has a history of reproducible studies,” he said.  More from Prevention: Can Probiotics Help You Lose Weight?