A sweeping new study published in the journal Nature Medicine has found that high consumption of ultra-processed foods — think packaged biscuits, ready-to-eat noodles, flavoured chips, and sugary beverages — is strongly associated with accelerated brain ageing and a significantly elevated risk of early cognitive decline.

How the Study Was Conducted

Researchers from University College London and the Brazilian PROCC cohort tracked 11,200 adults aged 35 to 74 over a 10-year period, using detailed dietary questionnaires combined with regular cognitive assessments and, for a subset of 1,800 participants, structural MRI brain scans.

The study found that participants who consumed more than four servings of ultra-processed foods daily showed cognitive test scores consistent with brains 2.8 years older than their chronological age — a statistically significant finding even after controlling for education, physical activity, and socioeconomic status.

The Mechanism: Inflammation and Gut Health

While the study was observational and could not establish direct causation, the researchers hypothesise that the link runs through chronic low-grade inflammation triggered by artificial emulsifiers, preservatives, and the displacement of fibre-rich whole foods from the diet — all of which negatively affect the gut microbiome and, through the gut-brain axis, neurological health.

What You Can Do

Dietitians recommend gradually replacing ultra-processed items with whole alternatives: fresh fruit instead of fruit-flavoured snacks, homemade dal instead of packaged instant noodles, and water or fresh buttermilk instead of aerated drinks. Small, consistent changes over months yield measurable improvements in inflammatory markers.