In the study, from the Université Laval in Quebec and published online in December 2013 by the British Journal of Nutrition, obese men and women followed a 12-week weight-loss diet followed by another 12 weeks of supervised but unrestricted weight maintenance. Half of the 125 subjects took probiotics-two capsules of Lactobacillus rhamnosus daily. Though there were no differences among the men in each group, the women in the probiotics group lost significantly more weight than the placebo group (9.7 pounds versus 5.7 pounds, on average, respectively). What's more, while women on the placebo gained weight back during the maintenance period, those taking the probiotic continued to lose weight-about another 1.8 pounds.
The difference between men and women may have to do with another notable finding: In the gut flora of the women, but not the men, there was a significant decrease of a particular family of bacteria that has been linked in one way or another to obesity by many studies. The relationship is murky at best, but the researchers posit that the reduction of these Lachnospiraceae bacteria may have played a role in the participants' sustained weight loss, including possibly helping to reduce an overabundance of leptin in the blood at the end of 24 weeks. High circulating levels of leptin, a hunger-regulating hormone produced by fat cells, is common among obese individuals.
The research was sponsored by Nestle, which provided the strain of L. rhamnosus that it uses in some of its yogurts in Europe and performed some of the analyses. Lucklily, L. rhamnosus can be found stateside in products such as Nancy's cultured dairy and soy yogurt and drinkable-yogurt-like kefir from Lifeway. The culture is also available as a supplement from a number of brands.
Yogurt with added probiotic cultures is well established as a keystone of health-conscious consumerism. Nutritionists parade it as a breakfast go-to and sour cream substitute. The Greeks are ceding fridge space to Australia's Noosa and the generically advertised "European" Müller (a German venture sold in the U.S. in partnership with Quaker, which has yet to bring its probiotic line overseas). Jamie Lee Curtis used it to stay regular until the start of 2014 when she was bumped as Activia's spokesperson in favor of Reba McEntire, Laila Ali and Travis Stork, M.D., of "Bachelor" and "The Doctors" fame.
- by Amanda Schupak