Daily probiotic supplementation may support the treatment of depression in older adults. This is suggested by a small but carefully conducted clinical pilot study published on June 17, 2026, in the Journal of the American Geriatrics Society (DOI: 10.1111/jgs.70530).
The twelve-week, placebo-controlled, double-blind study included 58 adults aged 60 and over with moderate depression. All participants continued their usual antidepressant medication. One half additionally received approximately six billion colony-forming units daily of the bacterial strains Lactobacillus helveticus and Bifidobacterium longum, while the other half received a placebo.
Both groups showed improvement over the course of the study. However, the probiotic group demonstrated a statistically significantly greater reduction in symptoms of depression and anxiety. Additionally, their blood levels of the neurotransmitter BDNF (Brain-Derived Neurotrophic Factor), which is important for nerve cell health and provides a mechanistic clue to the gut-brain axis, increased.
The probiotic did not significantly improve quality of life—likely because the number of participants was too small for this outcome. Researchers led by Dr. Saibal Das and Dr. Abhinaba Ghosh from India are now planning a larger follow-up study to confirm these results. They emphasize that probiotics should complement, not replace, standard therapy. The findings are promising but preliminary.
