New research from Monash University, the University of São Paulo, and Deakin University has found that diets high in ultra-processed foods can negatively affect brain function, particularly reducing the ability to focus and increasing the risk of dementia.
Published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, the study analysed the diets and cognitive health of more than 2,100 dementia-free Australian adults who were middle-aged and older.
The findings show that even small daily increases in ultra-processed food (UPF) consumption are linked to noticeable declines in attention span, even among individuals who otherwise follow a healthy diet.
Lead researcher Dr Barbara Cardoso from Monash University explained that the results highlight a strong connection between industrial food processing and cognitive decline. She noted that a 10% increase in UPF intake is roughly equivalent to eating an extra packet of chips per day.
The study found that each 10% rise in ultra-processed food consumption was associated with a measurable reduction in attention and processing speed, reflected in lower scores on standard cognitive tests.
On average, participants obtained about 41% of their daily energy from UPFs, closely matching the national Australian average of 42%.
Ultra-processed foods include items such as soft drinks, packaged snacks, and ready-made meals. Researchers emphasised that these effects occur even when overall diet quality is considered healthy, suggesting that the level of processing itself plays an important role.
Dr Cardoso explained that industrial food processing can damage the natural structure of foods and introduce additives or chemical compounds that may affect brain health. She added that this indicates cognitive risks are not only linked to missing healthy foods but also to consuming highly processed ones.
The study also found that higher UPF consumption was associated with increased risk factors for dementia, such as obesity and high blood pressure, which can be managed to support brain health.
While no direct link was found between UPFs and memory loss, researchers highlighted that attention is a key foundation for learning, reasoning, and problem-solving.
The research was conducted by experts from Monash University, the University of São Paulo, and Deakin University, using data from the Healthy Brain Project supported by multiple international research and health organisations.
