What is the evidence that probiotic supplementation can affect mood and mental well-being?

Psychobiotics are live bacteria (probiotics) or other products (prebiotics) that when ingested confer mental health benefits through interactions with commensal gut bacteria” (Dinan et al., 2013; Foster, 2017; Sarkar et al., 2016). The potential of “psychobiotics” as interventions in psychiatry is of great interest. Evidence to support a beneficial effect of probiotics on mental health is accumulating, including a small body of work in healthy individuals and clinical populations related to mental health. A summary of these studies is found in Table 1.  Keep an eye on this research domain—there are a lot of studies in the pipeline that will help turn the hype into hope.

Dinan, T.G., Stanton, C., Cryan, J.F., 2013. Psychobiotics: a novel class of psychotropic. Biol Psychiatry 74, 720-726.

Foster, J.A., 2017. Targeting the Microbiome for Mental Health: Hype or Hope? Biol Psychiatry 82, 456-457.

Sarkar, A., Lehto, S.M., Harty, S., Dinan, T.G., Cryan, J.F., Burnet, P.W., 2016. Psychobiotics and the Manipulation of Bacteria-Gut-Brain Signals. Trends Neurosci 39, 763-781.