Ultra-processed foods: Study finds more frequent silent brain damage

A diet high in ultra-processed foods is associated with more unnoticed damage in the brain, according to a Canadian study. Researchers at McMaster University's Population Health Research Institute analyzed data from 8,783 adults aged 35 to 69 with no known heart disease. The work was published on Oct. 15, 2026, in the journal JAMA Network Open. Using MRI, the researchers looked for silent brain infarcts and damage to small blood vessels that cause no symptoms.

Participants with the highest consumption had 40% higher odds of such lesions than those with the lowest, according to the study. Among the heaviest consumers, ultra-processed products accounted for about 45% of daily servings, compared with 16% among the lightest. The association was more pronounced in women, although this analysis was not planned in advance. Memory and thinking tests showed hardly any differences. "I frankly did not expect this result," said lead author Russell de Souza.

The authors stress the limitations: all values were measured at only one point in time, so the study shows an association but no proof of cause. Diet was recorded by questionnaire, and heavy consumers on average had lower incomes, exercised less and more often had diabetes. Longer studies with repeated MRI scans are needed, de Souza said; follow-up is ongoing. The findings are general information and do not replace medical or dietary advice.