Can probiotics improve cognitive function?

A recently published meta-analysis (essentially an analysis of multiple clinical studies) attempted to answer an important question: Can probiotics help older adults think better?

Key Research Findings
The analysis found that probiotics significantly improved cognitive performance compared to a placebo in older adults already experiencing memory and thinking difficulties. Study participants were between 60 and 82 years old, with many having cognitive impairment related to Alzheimer’s disease.

The research examined various probiotic formulations, primarily containing Lactobacilli and Bifidobacteria strains. Treatment periods ranged from 4 to 52 weeks, though 12-week interventions were most common across the studies.

Why? Understanding the Gut-Brain Connection
The relationship between gut bacteria and brain function becomes increasingly important with age. Older adults typically have less diverse gut microbiota than younger people, and those in long-term care facilities show even greater reductions in bacterial diversity compared to those living independently.

Probiotics may support cognitive health through several biological mechanisms. They can reduce inflammation throughout the body, improve blood sugar regulation, and decrease oxidative stress; these are all factors that contribute to brain aging and cognitive decline. Chronic inflammation and poor glucose control have been consistently linked to increased dementia risk.

Animal research has provided additional understanding of how gut bacteria influence brain function. Studies show that probiotics can reduce stress responses and increase levels of GABA, a neurotransmitter that promotes calmness and mental clarity. Some research also suggests that certain probiotics can increase brain levels of DHA, an omega-3 fatty acid essential for proper brain function.

Two surprising results
I was particularly interested in two takeaways from the study. First, single-strain probiotics actually seemed to work better than multi-strain probiotics for improving cognitive function. Second, the best benefits appeared in situations where participants took probiotics for 12 weeks or less.

To be honest, I’m at a loss for words about these two conclusions, except that I was surprised by both of them.

Conclusion
Current evidence suggests that probiotics may offer cognitive benefits specifically for older adults who already have memory or thinking problems. The supplements may be particularly helpful for those with more significant cognitive difficulties.

Probiotics are generally considered safe with minimal side effects and have many benefits beyond just improved cognition. For those reasons, we can heartedly recommend them. We look forward to seeing further high-quality studies that will help determine the best probiotic strains, optimal dosages, and treatment duration for cognitive health.

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