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Fibre's role in health and longevity
Most adults consume less than half the recommended daily fibre, despite its proven benefits for physical and cognitive health, research shows.
Fibre-a carbohydrate resistant to digestion-passes through the gut largely intact. It enlarges stools, prolongs satiety, and moderates blood sugar spikes. Studies link higher wholegrain intake to lower body mass index and reduced abdominal fat.
Lifespan and disease prevention
John Cummings, emeritus professor of experimental gastroenterology at the University of Dundee, calls fibre an "essential nutrient" after a review he co-authored found that adults consuming the most fibre faced a 15-30% lower mortality risk than those eating the least. Meeting the 30-gram daily target could prevent 13 deaths per 1,000 people by reducing risks of coronary heart disease, stroke, type 2 diabetes, and colon cancer.
The strongest benefits appeared at 25-29 grams daily. A medium jacket potato with baked beans and an apple provides roughly 15.7 grams; a 30-gram handful of nuts adds another 3.8 grams.
Gut-brain connection
Fibre fuels the gut microbiome, producing short-chain fatty acids like acetate, propionate, and butyrate. These compounds supply cellular energy and are tied to lower mortality, says Cummings.
Karen Scott, professor of gut microbiology at the University of Aberdeen, highlights butyrate's role in maintaining the gut lining, which may block harmful substances from entering the bloodstream and affecting the brain.
"The more fibre you eat, the more butyrate is produced, then the better your cognition can be retained."
Karen Scott, University of Aberdeen
Cognitive benefits and research findings
A 2022 study of over 3,700 adults found that those with the highest fibre intake had a lower dementia risk, while another study in adults over 60 linked higher fibre diets to improved cognitive function. A recent randomised trial with twin pairs showed that a daily prebiotic fibre supplement enhanced cognitive test performance within three months, alongside microbiome changes such as increased Bifidobacterium.
Mary Ni Lochlainn, clinical lecturer in geriatric medicine at King's College London, who led the trial, calls the microbiome a "malleable" resource for combating age-related decline. "It's an untapped area that could make growing older easier," she says.
Mental health and inflammation
Butyrate also appears to benefit mental health, with links to reduced depression, better sleep, and improved wellbeing. Scott's team found that Alzheimer's patients had higher pro-inflammatory markers and fewer butyrate-producing bacteria in their stool samples, supporting the gut-brain link.
Long-lived individuals tend to have diverse gut microbiomes, which varied fibre sources-nuts, fruits, vegetables-help sustain.
Simple ways to boost fibre intake
Increasing plant-based foods is key. Pulses like peas, beans, and lentils are fibre-rich; blending chickpeas into pancake batter or adding peas to pasta are easy tweaks. Swapping white bread and pasta for wholegrain versions helps, as does choosing wholegrain breakfast cereals. Snacks like popcorn, apples, seeds, and nuts further raise intake.
For those with chewing or swallowing difficulties, such as Parkinson's patients, fibre supplements offer a practical alternative.
"Increasing your fibre intake is really the single most beneficial thing people can do for their overall health."
Karen Scott, University of Aberdeen
