Ever heard of ‘Healthy gut, healthy you’? Well, that adage may be true for the brain as well. As people age, what’s beneficial for the gut may also be beneficial for the brain. A study on twins found that some commonly available and cheap daily protein and prebiotic supplements can improve memory for people in their 60s.

The study, conducted by researchers at King’s College London, found that taking daily prebiotic supplements improved memory test scores in people over the age of 60. The findings are published in Nature Communications, and further explain the strong connection between gut health and brain function.
Researchers looked into the two common plant fiber prebiotics: inulin, a dietary fiber, and fructooligosaccharide (FOS), a plant-based carbohydrate often used as a low-calorie sweetener. They found that these prebiotics help feed beneficial gut bacteria, which have been linked to cognitive benefits in animal studies.

The study had 36 pairs of twins over the age of 60, which helped the researchers to separate genetic and environmental influences on cognitive health. Each pair was split, with one twin receiving a daily prebiotic in protein powder, while the other received a placebo in protein powder. After 12 weeks, the twins who unknowingly consumed inulin or FOS scored higher on cognitive tests, particularly in memory and learning. They also found slight changes in gut microbiomes, with increased levels of Bifidobacterium, a beneficial bacteria previously linked to cognitive improvements in mice. Previous studies on mice have shown that Bifidobacterium reduces cognitive deficits by regulating gut-brain connections.

“We are excited to see these changes in just 12 weeks. This holds huge promise for enhancing brain health and memory in our aging population,” Mary Ni Lochlainn, a geriatric medicine researcher at King’s College London, said when the findings were published in March 2024.
“Unlocking the secrets of the gut-brain axis could offer new approaches for living more healthily for longer.”

Scientists have long studied the gut-brain axis, which is a communication network between the digestive system and the brain. Some experts even refer to the gut as the body’s ‘second brain’. However, how these two nervous systems work together remains a mystery.

A recent twin study at KCL suggests that eating certain ‘brain foods’ may be a promising way to treat cognitive decline. Though some prebiotics improve cognitive function in an aging brain, like memory and processing times, they do not appear to have significant physical benefits.
“These plant fibers, which are cheap and available over the counter, could benefit a wide group of people in these cash-strapped times. They are safe and acceptable too. Our next task is to see whether these effects are sustained over longer periods and in larger groups of people,” geriatrician Claire Steves at KCL adds.
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