Minding your meals: How fibre protects the brain
A high-fibre diet is also now believed to be particularly important for brain health, explains Scott. The presence of the fatty-acid butyrate helps maintain the lining of the gut, she says, thus reducing the risk of harmful substances entering the bloodstream and affecting the brain.
That’s why the gut microbiota can improve cognition. “The more fibre you eat, the more butyrate is produced, then the better your cognition can be retained.”
A 2022 study involving over 3,700 adults found that high dietary fibre intake was linked to a lower risk of dementia among individuals who had the highest fibre intake. Those who ate the least showed an increased risk. Similarly, another study among adults over 60 for instance, found that those who had diets higher in dietary fibre showed increased cognitive function.
While the above findings were correlations, a more recent randomised control trial of twin pairs also identified a causal impact on fibre and cognition. Those who consumed a daily prebiotic fibre supplement showed improved results in cognitive tests in three months compared to those who had a placebo. Prebiotics are simple fibres that benefit bacteria in the gut and can be consumed as supplements. Analysis of stool samples revealed that the fibre supplement changed the participants’ gut microbiome, with increased levels of beneficial bacteria, such as Bifidobacterium.
Mary Ni Lochlainn, clinical lecturer in geriatric medicine from Kings College London, led the study, and says it holds promise of using diet to help enhance brain health and memory in the older population. “The exciting thing about the microbiome is that it’s malleable and certain microbes seem to be associated positively with health.”