‘Compelling’ Evidence for Probiotics in Treatment of Depression

March 21, 2017
Probiotics for depression

Two recent studies support a role for probiotics in the treatment of depression symptoms.

A review and meta-analysis published in the Annals of General Psychiatry found that in the bulk of the 10 studies analyzed, probiotics reduced all measures of depressive symptoms. The strain of probiotic, dosing, and treatment duration, however, varied widely across the studies.

“The evidence for probiotics alleviating depressive symptoms is compelling,” researchers concluded, “but additional double-blind randomized control trials in clinical populations are warranted to further assess efficacy.”

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Meanwhile, in a study published in Scientific Reports, researchers observed that the gut microbiome of mice subjected to chronic stress had reduced levels of the probiotic bacteria Lactobacillus. With Lactobacillus loss, they found, depression symptoms emerged. But when they added Lactobacillus to the animals’ food, they returned almost to normal.

“A single strain of Lactobacillus," said lead researcher Alban Gaultier, PhD, of the University of Virginia School of Medicine in Charlottesville, “is able to influence mood.”

Dr. Gaultier and colleagues determined the drop in Lactobacillus in the gut raised the level in the blood of the metabolite kynurenine, which has been shown to drive depression. They next plan to study the effects of Lactobacillus in humans with depression.

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“The big hope for this kind of research is that we won't need to bother with complex drugs and side effects when we can just play with the microbiome,” said Dr. Gaultier. “It would be magical just to change your diet, to change the bacteria you take, and fix your health—and your mood.”

 —Jolynn Tumolo


Marin IA, Goertz JE, Ren T, et al. Microbiota alteration is associated with the development of stress-induced despair behavior. Scientific Reports. 2017 March 7;7:43859.

Wallace CJ, Miley R. The effects of probiotics on depressive symptoms in humans: a systematic review. Annals of General Psychiatry. 2017 February 20;16:14.

Probiotic found in yogurt can reverse depression symptoms in mice, UVA finds [press release]. Charlottesville, VA: UVA Health System; March 7, 2017.