OK, pregnant women may not crave bacteria like they do kosher dills and Heath Bar crunch, but taking probiotics may lower the risk of allergies for their offspring according to a new analysis of past studies. The research, noted on Reuters, is published online in the journal Pediatrics.
"Based on our findings, probiotics have a protective effect against allergies, but we still have things to learn before we can give general advice to the public," researcher Erick Forno of Children's Hospital of Pittsburgh, told Reuters.
Forno's team analyzed the results of 25 trials of supplements given during pregnancy or within the first year of a child's life. All of the studies compared mothers and babies randomly assigned to take probiotics with those given placebo supplements. Participants were given probiotic doses daily, and in some cases more than daily, for a few months to a year. The trials tracked whether kids later tested positive for common allergies like peanut or pollen. They also indicated if the kids wheezed or showed signs of asthma based on a questionnaire given to parents.
Babies who were exposed to probiotics in the womb and received supplements after birth had a 12 percent lower risk of allergies in the following months and years than kids who didn't. They didn't, however, have a lower risk of asthma.
Forno told Reuters that the new findings may help bolster the so-called hygiene hypothesis. "As nations have become more industrialized and developed, they have also become cleaner, and therefore our exposure to microbes early in life has decreased, and this has decreased infections," he said. The hygiene hypothesis posits that the cleaner environment may have led to an increase in allergies and asthma. (A cleaner environment also leads to less instances of food-born illness. But in case you do suffer from salmonella, probiotics may help with that as well.)
"The theory is that such exposures in early life helped our immune system to learn how to ‘self regulate' and recognize what to fight and what not to," he said. "Our hope is that with the results from our study, researchers will move on from trying to determine ‘if' probiotics help prevent allergies, and into ‘how' or what the best approach may be."