What’s good for the gut in older adults may also be good for their brains. A groundbreaking twin study found that daily protein and prebiotic supplementation improved memory performance in people over 60.
The results of this study, published early last year, are thought-provoking, especially considering that the same visual memory and learning tests have been used to detect early signs of Alzheimer’s disease.
This double-blind study involved two inexpensive, plant-based fiber prebiotics that are available in pharmacies around the world.
Prebiotics are non-digestible substances that help stimulate intestinal microflora. One type of such supplement is inulin, a fructan-based dietary fiber. Another is fructooligosaccharides (FOS), plant-based carbohydrates commonly used as a natural low-calorie sweetener.
To test the effects of these supplements on the aging brain, researchers from King’s College London recruited 36 pairs of twins aged 60 and over.
Each pair of twins was randomly divided into two groups: one group took a protein powder containing prebiotics daily, and the other group took a protein powder containing a placebo daily.
Three months later, on cognitive tests, the twins who were unaware of the inulin or fructooligosaccharide intake tended to perform better.
Furthermore, daily dietary fiber intake was associated with minor changes in the gut microbiota of twins. For example, twins taking inulin or fructooligosaccharides had higher numbers of beneficial bifidobacteria.
Studies in mice have shown that bifidobacteria may reduce cognitive impairment by modulating connections between the gut and the brain.
”We’re thrilled to see these changes in just 12 weeks. This has significant implications for improving brain health and memory in older adults,” said Mary N. Lockley, a geriatrics researcher at King’s College London, when the study results were published in March 2024.
”Unlocking the secrets of the gut-brain axis could enable people to live healthier, longer lives.”
King’s College houses the UK’s largest adult twin registry, and twin studies are vital in understanding the influence of genetics and environment on human health.
Previous studies in rodents have shown that high-fiber supplements such as inulin and fructooligosaccharides can “feed” the colonic microbiota, allowing “good” bacteria to thrive.
Certain bacteria have also been linked to improved cognitive function in mice and humans.
Growing evidence suggests a close connection between the gut and the brain. Some experts are now convinced of these findings, even calling the gut the body’s “second brain.”
A recent study of twins conducted at King’s College London suggests that eating certain “brain-boosting foods” may be a promising approach to treating cognitive impairment.
Although prebiotics may improve some aspects of cognitive function in older adults, such as memory and processing speed, there do not appear to be significant physiological benefits.
Although inulin and fructooligosaccharides are important factors for maintaining musculoskeletal health, muscle loss was not improved in the older twins who took high-fiber supplements.
”These inexpensive, over-the-counter plant fibers can benefit a wide range of people during these times of economic hardship. They are safe and readily available,” said Claire Stevens, a geriatrician at King’s College London.
”Our next task is to see if these effects can be maintained over a longer period of time and in a larger population.”
Most of the twins in this study were female. Although the researchers adjusted the results for gender differences, they also acknowledged that some selection bias may have been present in the KCL twin cohort.
In other words, women are more likely to develop Alzheimer’s disease, and studies like these support the emerging view that cognitive decline is not always a brain disease and may also be linked to external factors.
The gut is closely linked to many body systems, including the immune and central nervous systems. Supplementing the gut microbiota with certain prebiotics and probiotics may pave the way for the treatment of various diseases.
Post time: Dec-24-2025