Probiotic add-on shows modest mental health benefit in older adults
A small trial in India found seniors taking probiotics with antidepressants had slightly larger gains in depression and anxiety symptoms than placebo recipients.
By Priya Raghavan · Science Reporter
3 min read
A daily probiotic supplement was linked to modest extra improvement in depression and anxiety symptoms among older adults already taking antidepressants, according to research published in the Journal of the American Geriatrics Society. The findings add early clinical evidence to research on how gut bacteria may affect mental health, though the study was small and its authors said larger trials are needed.
Wiley, which released details of the study, said the pilot trial included 58 adults in India who were at least 60 years old and had moderate depression. All participants continued standard antidepressant care during the study.
Researchers randomly assigned participants in equal numbers to receive either a probiotic supplement or an inactive placebo each day for 12 weeks. The team then followed the participants for another 12 weeks to assess whether any changes persisted.
How the trial measured change
The investigators used established rating scales for depression and anxiety to compare outcomes between the two groups, according to Wiley. They also measured serum brain-derived neurotrophic factor, or BDNF, a protein involved in nerve cell growth, maintenance and survival that is often studied in mental health research.
The study also examined participants’ gut bacteria through fecal microbiota profiling. That method allows researchers to study the mix of microbes living in the digestive tract.
Both the placebo group and the probiotic group improved during the trial, Wiley said. Participants who received probiotics had somewhat greater reductions in depression and anxiety symptoms than those who received placebo, but the researchers did not find clear added improvement in overall quality of life.
Gut-brain research context
The trial fits into a growing area of research on the gut-brain connection. Scientists use that term to describe links between the digestive system, the microbes that live there and brain function.
Probiotics are live microorganisms used to support a healthier balance of gut bacteria. Researchers have been testing whether they can complement standard treatment for conditions including depression and anxiety, but the evidence remains developing.
The journal reference describes the work as a randomized, double-blind, placebo-controlled, multi-center pilot trial. Its title identifies the study population as geriatric patients with moderate unipolar depression.
Because the study enrolled a limited number of participants, the results should be treated as preliminary. The trial does not establish which patients would be most likely to benefit, how large the effect might be in a broader population or whether the same results would appear in larger studies.
Dr. Saibal Das of the Indian Council of Medical Research — National Institute for Research in Bacterial Infections in Kolkata, a co-corresponding author, said the team is planning a larger clinical trial because of the encouraging results.
Co-corresponding author Abhinaba Ghosh of Tata Medical Center in Kolkata said his goal is to develop affordable health care approaches that can reach more people and have public health value.
This story draws on original reporting from ScienceDaily.