Gut Health and Memory: Twin Study Reveals Benefits of Protein and Prebiotic Supplements for Over 60s

A recent study conducted on twins indicates that daily intake of protein and prebiotic supplements may enhance memory test scores in individuals aged 60 and above. Published in 2024, these findings are particularly noteworthy as the visual memory and learning test used in the study is also employed to detect early indicators of Alzheimer's disease.

The double-blind trial evaluated two specific plant-fiber prebiotics: inulin, a dietary fiber, and fructooligosaccharide (FOS), a plant carbohydrate. Prebiotics are non-digestible substances known to stimulate beneficial gut microbes.

Study Design and Key Findings

Researchers at King's College London enrolled 36 pairs of twins, all aged 60 or older, for the study. In a controlled design, one twin from each pair received a daily prebiotic mixed with protein powder, while the other received a placebo powder.

After three months, the twins who received either inulin or FOS generally achieved higher scores on a cognitive test.

The Gut-Brain Connection Explored

The daily fiber supplements were associated with subtle yet significant changes in the participants' gut microbiome. A notable increase in beneficial Bifidobacterium was observed in individuals taking inulin or FOS. Previous research on mice suggests that Bifidobacterium may play a crucial role in reducing cognitive deficits by positively influencing gut-brain connections.

Expert Insights and Future Prospects

Mary Ni Lochlainn, a geriatric medicine researcher at King's College London, commented on the positive implications of the findings.

The observed changes within 12 weeks show promise for improving brain health and memory in the aging population.

She added that understanding the gut-brain axis could provide new methods for healthier longevity.

The study leveraged King's College London's status as home to the UK's largest adult twin registry, making twin studies valuable for distinguishing genetic and environmental effects on health. This approach complements previous research on rodents, which indicates that high-fiber supplements such as inulin and FOS can support the colon's microbiome, fostering the growth of beneficial bacteria. Some of these bacteria have been linked to improved cognitive function in both mice and humans. While the relationship between the gut and the brain is a growing area of research, the exact mechanisms are not yet fully understood.

An Affordable and Accessible Intervention

The KCL twin study suggests that dietary interventions may be a promising avenue for addressing cognitive decline, complementing existing research on nutrients that may slow its progression. Claire Steves, a geriatrician at KCL, emphasized the practical advantages of this approach. She noted that these plant fibers are affordable and widely available, potentially benefiting a broad demographic.

Steves also added that future research would focus on evaluating the sustained effects over longer periods and in larger populations.

Nuances and Next Steps

While the prebiotics appeared to enhance aspects of cognitive function, such as memory and processing times, the study did not observe significant physical benefits, including improvements in muscle loss. The participant cohort was predominantly female; researchers adjusted for sex differences but acknowledged potential selection bias.

This research contributes to the understanding that cognitive decline may involve external factors beyond the brain. The study was published in Nature Communications.