Fiber Supplement Improves Brain Function, Study Shows

Cheap, accessible fiber supplements can improve brain function in older adults in as little as three months, a new study shows.

Taking a daily prebiotic supplement can promote positive changes in the gut microbiota, which can lead to improved brain function in adults over 60 years old, according to a new study.

The study, published in Nature Communications, demonstrates that this accessible intervention successfully improved study participants’ performance on a cognitive test that has been designated as an early identifier of Alzheimer’s disease.

“The prevalence of dementia is growing globally, but as the population ages, recognition of cognitive changes that can happen as part of healthy ageing will become increasingly crucial for researchers and clinicians working with older people,” the study authors wrote.

The researchers also set out to determine whether the supplement, which consisted of plant fiber supplements inulin and fructo-oligosaccharides, could improve muscle strength, but no improvement in this area was observed throughout the trial.

For the study, researchers at TwinsUK, an adult twin registry based at King's College London in the United Kingdom, split up 36 pairs of twins — or 72 individuals — and assigned one twin a daily prebiotic and the other a placebo for a period of 12 weeks. The researchers and participants were not aware of which supplement they had been assigned until the study was over. All participants also took a daily protein supplement and practiced resistance training, both of which were aimed at improving muscle strength.

In the end, they found that the fiber supplement was well tolerated and resulted in changes in the gut microbiome, particularly leading to an increase in a “good” bacteria called Bifidobacterium. Participants who took the prebiotic also did better on cognitive tests in terms of reaction time and processing speed, including the Paired Associates Learning test, which is considered an early identifier for dementia from Alzheimer’s.

The gut microbiome is made up of the bacteria, archaea, viruses, and eukaryotic microbes that reside in the gut, their collective genomes, and the surrounding environment. Recent research suggests that the gut microbiome may be important for cognitive functioning in aging, though the resilience of the gut microbiome reduces with age.

“There is a growing body of evidence supporting a gut-brain axis, a bidirectional communication system between central and enteric nervous systems, in which the gut microbiota plays a key influential role,” the researchers wrote.

In line with previous research, this study found a positive correlation between increases in the cognitive factor score and the relative abundance of Actinobacteria.

The authors said, “Our results demonstrate that cheap and readily available gut microbiome interventions hold promise for improving cognitive frailty in our ageing population."