ABERDEEN, Scotland — Fiber powers the gut microbiome and shields the brain from decline, according to microbiologists at the University of Aberdeen. Professor Karen Scott calls boosting fiber intake the top dietary move for cognitive health. Her research highlights how this indigestible carbohydrate fuels beneficial gut bacteria, producing butyrate that protects the gut lining and supports brain signaling via the gut-brain axis.

A 2022 study of over 3,700 adults tied the highest fiber consumption to lower dementia risk. Participants eating the least fiber faced higher odds of cognitive impairment. Adults over 60 with fiber-rich diets scored better on cognitive tests, researchers reported.

Those benefits go causal, not just correlational. A recent randomized trial with twin pairs gave one twin daily prebiotic fiber supplements, the other a placebo. After three months, the fiber group aced cognitive tests. Stool analysis showed surges in Bifidobacterium and other good bacteria, along with more butyrate — a fatty acid linked to sharper thinking, better sleep and less depression.

Fiber’s perks extend beyond the brain. Emeritus Professor John Cummings of the University of Dundee co-authored a review showing top fiber eaters cut mortality 15-30% versus low consumers. At 30 grams daily, fiber slashes risks of coronary heart disease, stroke, type 2 diabetes and colon cancer. That adds up to 13 fewer deaths per 1,000 people, the analysis calculated.

People pack in fiber through everyday foods. Whole grains lower BMI and trim belly fat compared to refined grains. Pulses like peas, beans and lentils deliver big doses. Nuts, seeds, fruits and vegetables round out the list. Cummings notes diverse fiber sources build varied gut microbiomes, a hallmark of long, healthy lives.

Intake falls short worldwide. About 97% of U.S. men and 90% of women eat under half the recommended amount. Over 90% of UK adults miss the mark. Similar gaps plague other nations. Scott blames processed diets low in plants. Cummings deems fiber an essential nutrient for longevity.

Simple swaps help. Blend canned chickpeas into pancake batter. Toss peas into pasta. Swap refined grains for whole ones. These steps bulk stools, steady blood sugar and keep hunger at bay. The payoff: healthier bodies, stronger brains and longer lives.

Butyrate from fiber-loving bacteria bolsters wellbeing. Studies connect it to reduced mental illness and improved mood. As Scott puts it, more fiber means more butyrate, which means better cognition retention. Public health campaigns push these findings to combat widespread shortages.