Probiotics Affect on the Brain

Probiotics have been shown to “affect the brain activity linked to emotion and sensation”, says a recent study [1] from UCLA.

The previously proposed relationship between the gut flora profile and mood has been postulated based on preliminary data in rodents, preclinical data in humans, and a recent report in IBS patients. This study is the first in clinical settings to demonstrate the probiotic’s effect on GUT-BRAIN COMMUNICATIONS in HUMANS.

The study involved 36 healthy women with no GI or psychiatric symptoms. They were randomly assigned into 3 groups, each group given either 1) probiotic yogurt 2) yogurt with NO probiotic (heat-treated) or 3) no intervention for 4 weeks. The probiotics included in the study were Bifidobacterium lactis, Streptococcus thermophiles, and Lactobacillus bulgaricus.

Participants underwent functional magnetic resonance imaging (fMRI) before and after the intervention, to measure resting brain activity, as well as brain’s response to emotional-faces-attention tasks. The results showed that the long-term probiotic intake was associated with reduction in task-related response involving the affective, viscerosensory, and somatosensory cortices in the brain (49% cross-covariance; P =.004).

The gut-brain axis has been a rather well-recognized concept amongst peers in naturopathic medicine; however, there had not been much clinical research done to establish and support this connection.

This study opens up a path for future research to further elucidate the mechanisms of action in probiotics’ beneficial effects in patients with IBS or abnormal pain and stress responses associated with dysbiosis.

[1] Tillisch K, Labus J, Kilpatrick L, Jiang Z, Stains J, Ebrat B, Guyonnet D, Legrain-Raspaud S, Trotin B, Naliboff B, Mayer EA. Consumption of Fermented Milk Product with Probiotic Modulates Brain Activity. Gastroenterology. 2013 Mar 5. pii: S0016-5085(13)00292-8. doi: 10.1053/j.gastro.2013.02.043.