Warning over probiotics

A new study suggests that the muchvaunted health benefits of probiotics may in fact be negligible, and that in some cases the supplements could even be harmful. People ingest these live bacteria and yeasts—usually taken as supplements or in foods such as yogurt or kefir—in the belief that they can top up the “good” bacteria in their gut, reports LiveScience.com. Having a well-cultured “microbiome” has been linked with several health benefits, including reduced heart disease risk and improvements in mental health. But in one of the first studies to sample bacterial mix in the gut, rather than in excrement, researchers in Israel found that most people’s guts were in fact resistant to probiotics. In a separate study, the same team discovered that taking the supplement while on antibiotics could potentially exacerbate metabolic issues such as diabetes and obesity. Because antibiotics can kill off the natural mix of bacteria in the gut, the microbes from probiotic supplements can rapidly take over, delaying the return of the natural gut biome. Co-author Eran Elinav, from Israel’s Weizmann Institute of Science, says the findings call into doubt “the current dogma that probiotics are harmless and benefit everyone.”