Can Probiotics Make You Smarter? Maybe, If You're A Mouse

Probiotics have been sexy on the health food scene for a while now — there's an entire scientific association at work studying them, and mainstream publications recommend dietary sources of probiotics to readers. Anyone familiar with the evils of the "standard American diet" knows that eating lots of refined carbs and meat but little fiber will destroy your digestion. Replacing the "healthy bacteria" in the gut with probiotic supplements can help to restore digestive health. But can probiotics do even more? A British researcher has recently claimed that a yogurt-derived probiotic may improve cognitive function.

John Cryan, a neuroscientist at University College Cork, previously found that mice given probiotic Lactobacillus rhamnosus were less anxious than control group mice. Now, the researcher reports "We have unpublished data showing that probiotics can enhance learning in animal models":

His team tested the effects of two strains of bacteria, finding that one improved cognition in mice. His team is now embarking on human trials, to see if healthy volunteers can have their cognitive abilities enhanced or modulated by tweaking the gut microbiome.

Don't get too excited, though. This research, unpublished as it is, has not yet been reviewed by Cryan's peers in the scientific community to assess the quality of his still-unknown methods, data, and conclusions. It's even unclear what "cognitive function" means in this case — did the mice navigate a maze, play a game, or what? And, even if the studies were done perfectly and analyzed accurately, mice studies remain quite limited. A UCLA gut-brain researcher and friend of Cryan's cautions:

There is currently no evidence whatsoever, in humans or in animals, that gut bacteria can enhance brain function," Mayer says. "I know [Cryan] well, but I feel he's gone way overboard with his speculation based on a few mice studies.

It is well-established, though, that eating a healthy diet in general will improve your cognitive function. In particular, a Mediterranean diet rich in "oily fish, red wine, raw nuts, fresh vegetables, olive oil, herbs, and garlic" may reduce your risk of dementia. Yogurt is a good choice for adding naturally-occurring probiotics to your diet, but keep sugar content down by adding your own fruit (or you risk defeating the whole purpose, doing more harm to your gut bacteria than good).