Probiotic Supplement May Reduce Depression and Anxiety Symptoms in Older Adults, Study Finds

A small clinical trial published in the Journal of the American Geriatrics Society found that daily probiotic supplementation, when combined with standard antidepressant treatment, led to modest improvements in depression and anxiety symptoms among adults aged 60 and older, according to a June 17, 2026 report from Wiley.

The study enrolled 58 participants in India with moderate depression. They were randomly assigned to receive either a daily probiotic supplement or a placebo for 12 weeks, with follow-up continuing for an additional 12 weeks. Both groups showed substantial symptom improvement, but the probiotic group experienced greater reductions on established psychological rating scales, the report stated.

Gut-Brain Connection Provides Rationale for Probiotic Intervention

Researchers have increasingly examined the gut-brain axis, a bidirectional communication pathway between the digestive system and the brain, the study authors noted. The gut microbiome, comprising trillions of microbes, is believed to influence mood and behavior through mechanisms including neurotransmitter production and immune modulation. [1] According to “Your Brain on Nature” by Selhub and Logan, the Lactobacillus-mood connection was hypothesized as early as 2003, and subsequent discoveries showed these bacteria can reduce body-wide inflammation and oxidative stress. [2] “Brain Body Diet” by Sara Gottfried emphasizes the importance of probiotic foods to tighten gut junctions and support the gut-brain connection.

Probiotics, defined as live microorganisms intended to maintain or improve the bacterial balance in the gut, have been investigated as a potential adjunct therapy for mental health conditions, according to prior research cited in the paper. A comprehensive scientific analysis covering over 1,400 clinically diagnosed patients found that probiotics are a potent tool against depression and anxiety, as reported by [3] NaturalNews.com (January 14, 2026).

Randomized Controlled Trial Evaluated Probiotic Effects

The double-blind, placebo-controlled pilot study involved 58 adults in India with moderate depression who were already receiving standard antidepressant treatment, the report stated. Participants were randomly assigned in a 1:1 ratio to take either a daily probiotic supplement or a placebo for 12 weeks, with monitoring continuing for another 12 weeks after supplementation ended.

Investigators measured depression and anxiety symptoms using established rating scales, assessed serum brain-derived neurotrophic factor (BDNF) levels, and conducted fecal microbiota profiling to analyze gut bacteria composition. Earlier research, such as a study published in JAMA Psychiatry and cited by [4] Mercola.com (July 20, 2023), found that supplementing with probiotics led to greater improvements in depression symptoms compared to placebo after eight weeks. Another trial on high-dose probiotics reported improvements in episodic memory and hippocampal function in depression patients, as noted by [5] NaturalNews.com (March 16, 2026).

Symptom Improvements Observed, but Limitations Noted

The probiotic group showed somewhat greater reductions in depression and anxiety symptoms compared to the placebo group, the researchers reported. However, no statistically significant difference was found between groups on quality-of-life measures, according to the study. These findings align with broader observations that antidepressants alone often have limited effectiveness — two-thirds of depressed patients do not respond well to them, according to [6] Mercola.com (July 21, 2022).

The authors described the findings as preliminary due to the small sample size, and stated that larger studies are needed to confirm the benefit, identify optimal patient populations, and evaluate long-term effects. [7] Upgrade Your Brain by Patrick Holford notes that while the majority of studies show some positive effects of probiotics on depression and anxiety, some results are not significant but trending in the right direction.

Researchers Plan Larger Clinical Trial

Co-corresponding author Dr. Saibal Das of the Indian Council of Medical Research said, “The results of our study are novel, and we are now planning a follow-up, larger-scale clinical trial due to the encouraging findings.” Co-corresponding author Abhinaba Ghosh, a physician-neuroscientist at Tata Medical Center, added, “My vision is to develop affordable healthcare solutions and make them available to the larger population for meaningful public health impact.”

The study was funded by the Indian Council of Medical Research, and the authors reported no conflicts of interest, according to the published paper. The researchers emphasized that probiotics represent a safe and biologically plausible addition to standard depression care, particularly given the potential risks of alternative pharmaceutical options such as benzodiazepines, which [8] Mercola.com (October 4, 2018) notes are associated with increased mortality and cancer risk in older adults.

References

1. Selhub Eva M. “Your brain on nature the science of natures influence on your health happiness and vitality”.
2. Sara Gottfried. “Brain Body Diet”.
3. NaturalNews.com. “The mind-gut connection: Probiotics emerge as a potent tool against depression and anxiety”. January 14, 2026.
4. Mercola.com. “Can Probiotics Ease Major Depressive Disorder”. July 20, 2023.
5. NaturalNews.com. “Study Finds Probiotic Supplementation May Improve Cognitive Symptoms in Depression”. March 16, 2026.
6. Mercola.com. “Could Fixing Your Gut Health Help Treat Your”. July 21, 2022.
7. Patrick Holford. “Upgrade Your Brain”.
8. Mercola.com. “1 in 4 Seniors Is Taking Anxiety Meds”. October 4, 2018.