Probiotics May Help Improve Cognitive Function in People with Impairment, Study Finds
May 2025 — Henan University, China
A systematic review and meta-analysis led by researchers at Henan University suggests that probiotic supplements may improve cognitive function in people with cognitive impairment, especially when taken in the short term. The findings, published in PLOS ONE, add to growing evidence that the gut-brain connection plays a meaningful role in brain health.
The study, conducted by Miaomiao Ma and colleagues from the College of Nursing and Health at Henan University, reviewed data from 10 randomized controlled trials involving a total of 778 participants with cognitive impairment. Researchers found that taking probiotics—especially single-strain supplements for 12 weeks or less—was associated with measurable cognitive improvements.
Cognitive Boost Linked to Gut Health
The team analyzed data from clinical trials across China, Japan, and Iran, where participants with mild cognitive impairment or Alzheimer’s disease were given probiotics or placebo treatments. The cognitive function of participants was measured using standard tools such as the Mini-Mental State Examination (MMSE) and the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-cog).
Results showed that participants who received probiotics scored significantly better on cognitive tests, particularly when the MMSE was used. Those taking single-species probiotics saw the greatest benefits, while multi-species combinations were linked to more modest gains.
Short-Term Use Showed the Most Benefit
One of the key findings was the effect of duration: interventions lasting 12 weeks or less had a greater impact on cognition than those extending beyond that timeframe. Researchers suggest that probiotics may work best in the short term, though more long-term studies are needed.
The Gut-Brain Axis
The authors point to the gut-brain axis—the bidirectional link between the digestive tract and the central nervous system—as a likely mechanism. Probiotics are thought to:
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Reduce inflammation and oxidative stress
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Influence neurotransmitter levels like serotonin and GABA
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Improve gut barrier integrity, possibly protecting brain function
The team also noted that some probiotics have shown promise in reducing symptoms of anxiety and depression, which are often linked with cognitive decline.
Limitations and Next Steps
While the findings are promising, the researchers acknowledge limitations:
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The included studies were small and varied in quality
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Some used different cognitive assessment tools, which may have influenced outcomes
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Dosage and delivery methods (e.g., capsules vs. probiotic drinks) were inconsistent
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The long-term safety and effectiveness remain uncertain
Still, the meta-analysis adds momentum to the idea that targeting the microbiome could support brain health—particularly for people in early stages of cognitive decline.
A Potential Adjunct, Not a Replacement
The authors caution that probiotics are not a cure or replacement for current treatments, but they may serve as an adjunctive strategy for slowing cognitive decline. More studies are needed to determine the ideal strains, doses, and timing for maximum benefit.
