A new study found that taking a daily prebiotic supplement can improve scores in memory tests used to detect early signs of Alzheimer’s disease.
And to really control for genetic differences, the researchers enlisted several pairs of twins over age 60 to test it out.
These findings support earlier research that suggests changes in the gut microbiota can alter both muscle physiology and cognitive behavior.
Published in Nature Communications, this study featured 36 pairs of twins over 60 in a double-blinded trial. The trial incorporated two inexpensive, over-the-counter plant fiber prebiotics.
Prebiotics are nondigestible consumables that feed the bacteria and other organisms that live in the gut.
For the latest study, researchers at King’s College London used inulin, a dietary fiber in the fructan class, and fructooligosaccharide, a plant carbohydrate commonly used as a natural, low-calorie sweetener.
To test the effects of these supplements, the team split the twin pairs; one twin was given a daily prebiotic in a protein powder, while the other was given a daily placebo.
In general, after twelve weeks, the twin who took inulin or FOS scored higher on a cognitive test.
KCL is home to the United Kingdom’s largest adult twin registry. Researchers emphasize the importance of twin studies in differentiating between genetic and environmental influences on human health.
“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,” said Mary Ni Lochlainn, a geriatric medicine researcher at King’s College London.
Evidence of the link between gut and brain health is mounting, though the precise way these nervous systems coexist is not fully understood.
“Unlocking the secrets of the gut-brain axis could offer new approaches for living more healthily for longer,” said Lochlainn.
Previous rodent studies have found a link between high-fiber supplements and gut health, with experts maintaining that these supplements feed the microbiome and allow good bacteria to flourish.
The twins featured in the study were predominately female, which researchers acknowledge may contribute to selection bias. However, roughly twice as many women have Alzheimer’s disease than men, and studies like this support the idea that cognitive decline is not solely a disease of the brain.
A neurodegenerative condition, Alzheimer’s disease affects an estimated 7 million Americans.
The most common type of dementia, Alzheimer’s, is caused by a buildup of amyloid proteins in the brain, with risk factors including age, family history, unhealthy lifestyle behaviors and certain medical conditions.
While the latest study suggests prebiotics can improve cognitive functions like memory and processing time in the aging brain, they do not appear to deliver physical benefits. Despite inulin and FOS being critical to musculoskeletal maintenance, twins who took high-fiber supplements did not see any improvement in muscle strength.
Still, the efficacy and accessibility of these plant fibers offer a promising avenue for protecting the aging brain.
“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,” said geriatrician Claire Steves at KCL.
“Our next task is to see whether these effects are sustained over longer periods and in larger groups of people.”
