Brain Function Affected by Change in Gut Bacteria

At ULCA, researchers conducted a study that tested women who regularly consumed yogurt containing beneficial bacteria called probiotics, to see if they had any alteration in brain function compared to women who did not consume the probiotics in yogurt. The study showed that the women who regularly ate yogurt had an alteration in both a resting state and emotional recognition brain function.

Researchers speculated that by changing the bacteria’s environment in the gut, brain functionality could be augmented. The study was small, consisting of only 36 healthy women of ages 18-55. The women were divided into three groups: one group was given yogurt with probiotics twice a day for four weeks, one group was given a look-alike yogurt with no probiotics, and the third group did not have any yogurt. Comparing MRI scans taken before and after the study, researchers found that women who consumed the probiotic yogurt saw a decrease in insula, which processes and integrates body sensations, as well as in the somatosensory cortex during emotional-recognition testing. These women also saw a decrease in widespread engagement of the brain to deal with emotion, cognition, and sensory-related tasks.  The women who did not eat the probiotic yogurt had increased levels of brain network activity, spread out across more area. Furthermore, during the resting brain scan, women consuming probiotics had a higher connectivity of the brainstem to cognition, while the women not eating any yogurt saw increase of emotional and sensational connection to the brainstem.  The women eating the look-alike yogurt fit between the two extremes.  Researchers were astounded to find the various effects on the brain due to consumption of probiotics, such as the change in sensations as well as processes of emotional responses. The linkage of signals between the intestines and the brain will lead scientists to explore new routes of research.  These innovative news possibilities include changes in diet to test for varying levels of brain response and functionality.


1) Kirsten Tillisch, Jennifer Labus, Lisa Kilpatrick, Zhiguo Jiang, Jean Stains, Bahar Ebrat, Denis Guyonnet, Sophie Legrain-Raspaud, Beatrice Trotin, Bruce Naliboff, Emeran A. Mayer. Consumption of Fermented Milk Product with Probiotic Modulates Brain Activity. Gastroenterology, 2013; DOI: 10.1053/j.gastro.2013.02.043

2) University of California, Los Angeles (UCLA), Health Sciences (2013, May 28).

Changing gut bacteria through diet affects brain function. ScienceDaily. Retrieved May 29, 2013, from

By Lauren Horne

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