Ultra-processed foods may harm attention span and raise dementia risk factors, according to new research involving more than 2,100 adults.
Ultra-processed foods are becoming a larger part of everyday diets around the world, but scientists are increasingly warning that the convenience may come at a cost to brain health. New research from Monash University, the University of São Paulo, and Deakin University has found that even small increases in ultra-processed food consumption may impair the brain’s ability to focus and could heighten factors linked to dementia.
The study, published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, examined the diets and cognitive performance of more than 2,100 dementia-free middle-aged and older Australians.
Researchers discovered that higher intake of ultra-processed foods was associated with measurable declines in attention span and processing speed — even among people who otherwise followed healthy diets.
Even Small Dietary Changes Affect Attention
Lead author Dr. Barbara Cardoso, from Monash University’s Department of Nutrition, Dietetics, and Food and the Victorian Heart Institute, said the findings strengthen evidence linking industrially processed foods to cognitive decline.
“To put our findings in perspective, a 10 percent increase in UPFs is roughly equivalent to adding a standard packet of chips to your daily diet,” Dr. Cardoso said.
“For every 10 percent increase in ultra-processed food a person consumed, we saw a distinct and measurable drop in a person’s ability to focus.
“In clinical terms, this translated to consistently lower scores on standardized cognitive tests measuring visual attention and processing speed.”
Australians Getting Nearly Half Their Energy From UPFs
Participants in the study received about 41 percent of their daily energy intake from UPFs, closely matching Australia’s national average of 42 percent.
Ultra-processed foods include products such as soft drinks, packaged salty snacks, and ready-made meals—basically foods that are far removed from fresh, whole ingredients.
Researchers said the harmful effects were seen regardless of overall diet quality, including among people following Mediterranean-style diets. This suggests the level of food processing itself may contribute to the damage.
Food Processing May Drive Cognitive Decline
“Food ultra-processing often destroys the natural structure of food and introduces potentially harmful substances like artificial additives or processing chemicals,” Dr. Cardoso said.
“These additives suggest the link between diet and cognitive function extends beyond just missing out on foods known as healthy, pointing to mechanisms linked to the degree of food processing itself.”
Higher UPF consumption was also associated with more dementia risk factors, including conditions such as high blood pressure and obesity, both of which can be managed to help protect brain health.
Although the researchers did not find a direct link between UPFs and memory loss, they noted that attention is essential for many key mental functions, including learning and problem-solving.
Reference: “Ultra-processed food intake, cognitive function, and dementia risk: A cross-sectional study of middle-aged and older Australian adults” by Barbara R. Cardoso, Euridice Martinez Steele, Barbara Brayner, Xinyi Yuan, Lisa Bransby, Hannah Cummins, Yen Ying Lim and Priscila Machado, 23 April 2026, Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.
DOI: 10.1002/dad2.70335
The research used data from the Healthy Brain Project, which is funded by the National Health and Medical Research Council (NHMRC), the Alzheimer’s Association, the Dementia Australia Research Foundation, the Bethlehem Griffiths Research Foundation, the Yulgilbar Alzheimer’s Research Program, the National Heart Foundation of Australia and the Charleston Conference for Alzheimer’s Disease. Dr. Euridice Martinez Steele was funded by FAPESP (2023/16144-3), Dr. Priscila Machado by an NHMRC Emerging Leadership Fellowship (APP2034008) and Professor Yen Ying Lim by an NHMRC Career Development Fellowship (GNT1162645) and an Emerging Leadership Grant (GNT2009550).
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