Can Probiotics Help You Lose Weight?

July 9, 2013— -- Probiotics are so hot right now. Every week bring news of another benefit tied to these tiny bacteria (did you know they can affect the way you think?) which naturally congregate by the millions in your gut and intestines. Recent research has shown probiotics can aid digestion and ward off illness. And a new study, published in the British Journal of Nutrition, links one probiotic strain to fat loss. But can you trust the weight-reduction claims?

First, the science: A team of Japanese researchers split 210 overweight people into three groups. While everyone consumed a daily 7-ounce serving of fermented milk, two of the groups drank milk spiked with varying amounts of a probiotic called Lactobacillus gasseri SBT2055which past research has tied to fat loss. After 12 weeks, people slugging the probiotic milk formulas dropped roughly 8 to 9 percent of their visceral fat—a particularly unhealthy type that builds up around your heart and organs. Both probiotic groups also lost 1 to 3 percent of their belly fat, the study shows. (Check out the 10 best belly fat–blasting foods here!)

Your intestines manage the digestion and absorption of the foods you eat, explains study co-author Yukio Kadooka, a researcher with the Snow Brand Company in Japan. And it's possible the probiotic featured in the study lowers intestinal inflammation and aids digestion, both of which could prevent the buildup of body fat, Kadooka says.

But here's the first problem: The probiotic strain highlighted in this research isn't commercially available in the U.S., Kadooka says. The second problem: Like Kadooka's study, most of the research linking probiotics to weight loss have been conducted (or funded) by companies who sell products containing those same probiotics (including beauty products). Now, that doesn't mean the research isn't valid, says Jeremy Burton, PhD, deputy director of the Canadian Research and Development Centre for Probiotics. "There's nothing wrong with companies investing in studies, but it's better when the study is backed up by independent research," Burton adds.

So far, that independent research is either inconclusive or contradictory. A study published in the International Journal of Obesity found that while some strains of probiotics aid weight loss, others contribute to obesity. (There's even a thing called prebiotics. Here's what those are—and what they mean for your health!) "The research now is premature, and requires more analysis," says that study's co-author, Didier Raoult, MD, PhD, a Marseille, France-based microbiologist.

Your takeaway? Probiotics offer benefits "to be sure," Burton says, and research has supported the digestive-health claims of products like Dannon's Activia yogurt. But the jury's still out on probiotics when it comes to weight loss. "There's definitely a role for probiotics in dieting," Burton adds. "But were still teasing apart all the mechanisms involved." So for now, don't count on a probiotic to replace your treadmill or diet plan. Instead, check out the 25 Best Diet Tips…Ever!