The study reviewed 21 randomized controlled clinical trials up to December 2023, and explored whether probiotics could truly enhance aspects of human cognition and whether those effects varied by age. This research examined outcomes including memory, processing speed, executive function, verbal ability, and spatial skills, combining results through standardized mean difference (SMD) and confidence interval analysis.
The most strong benefits were observed among participants in later life. Probiotics significantly boosted overall cognitive performance (SMD = 0.40), information processing speed (SMD = 0.37), memory (SMD = 0.51), and spatial ability (SMD = 0.35). All improvements were statistically significant, with memory showing the strongest effect. These results suggest probiotics may play a valuable role in supporting aging brains, particularly when taken consistently for around 12 weeks at a daily dose of 2 × 10¹⁰ colony-forming units (CFU).
In early life, probiotics appeared to support executive function like skills tied to attention, problem-solving, and planning. The analysis found a modest but significant benefit (SMD = 0.30), pointing to potential developmental advantages.
For younger populations, effects were less broad but still noteworthy. The trials showed improvements mainly in verbal ability (SMD = 0.43), hinting that probiotics may subtly enhance language-related skills in this age group.
While probiotics have long been associated with gut health, this study strengthens the idea of a “gut-brain axis”—the communication link between digestive health and brain function. Also, the findings highlight that probiotics do not act as a one-size-fits-all supplement. Their cognitive effects appear to be age-dependent, which offers targeted benefits at different life stages.
For older adults, probiotics may hold promise as a non-invasive, natural strategy to maintain memory and processing speed, both of which tend to decline with age. For children, early support of executive function could aid in learning and development. Meanwhile, young adults may experience boosts in verbal performance, though broader benefits in this group remain less clear.
Overall, this research adds to a growing body of evidence linking probiotics to brain health. With aging populations worldwide and rising concern over cognitive decline, these findings could guide future recommendations for probiotic use.
Source:
Guo, H., Liang, Y., Qin, X., Luo, Q., Gong, X., & Gao, Q. (2025). Effects of probiotics on cognitive function across the human lifespan: a meta-analysis. European Journal of Clinical Nutrition, 1–16. https://doi.org/10.1038/s41430-025-01660-8
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