One daily serving of ultra-processed food may raise dementia risk – research
By CNN, April 30, 2026Increasing your daily consumption of ultraprocessed foods by 10% — roughly the equivalent of a small bag of potato chips — may raise your risk of dementia, even if you normally eat a healthy, plant-rich diet, according to a new study.
Ultraprocessed foods, or UPFs, make up about 53% of all calories consumed by adults in the United States, according to data from the US Centres for Disease Control and Prevention. Children obtain nearly 62% of their energy from UPFs.
“Our study showed that UPF consumption was associated with worse attention and higher dementia risk in middle-aged and older adults,” said lead author Barbara Cardoso, a senior lecturer of nutrition, dietetics and food at Monash University in Melbourne, Australia.
The study could only show an association, not a direct cause and effect. However, “this association was not changed by adherence to the Mediterranean diet, indicating that this is linked to food processing rather than simply food displacement,” Cardoso said.
The research is an important addition to the growing evidence showing the potential harms of ultraprocessed foods on the brain, said Dr. W. Taylor Kimberly, a professor of neurology at Harvard Medical School in Boston, who was not involved in the study.
Kimberly was the senior author of a similar study published in January that found increasing ultraprocessed food intake by 10% raised the risk of cognitive impairment by 16%, even among people who mostly ate plant-based diets.
“Together, these studies highlight that higher UPF consumption is consistently associated with poorer cognitive performance,” Kimberly said.
There is a positive finding for people who commit to lowering their UPF intake over time. His study found replacing ultraprocessed foods with minimally processed and whole foods over a five- to six-year period was linked with a 12% lower risk of cognitive decline.
Another study found that adults in their 50s and 60s who reduced unhealthy foods over a decade had an 11% lower risk of Alzheimer’s disease and dementia compared with those whose diets did not change.
The Mediterranean diet, which emphasises whole grains, fruits and vegetables, beans, seeds, nuts and extra-virgin olive oil, has been shown to reduce the risk of cancer, diabetes, heart disease, stroke and dementia.
Other plant-rich diets, such as the DASH and MIND diets, also focus on whole foods while limiting sugar, red meat and ultraprocessed foods. These diets have been linked to improvements in blood pressure, cholesterol, diabetes and overall heart health, all of which support brain health.
Ultraprocessed foods, however, contain little to no whole foods. Instead, ingredients are broken down into components and combined with additives such as artificial colourings, flavourings and emulsifiers. These are then processed into final products.
Such foods, often high in sugar, salt and fat, may lack essential nutrients needed for a healthy body and brain.
A 2022 study of 10,000 people found that those who ate the most ultraprocessed foods experienced a 25% faster decline in executive function and a 28% faster rate of overall cognitive impairment compared with those who ate the least.
Research on the health risks of ultraprocessed foods continues to grow. A 2024 review of 45 studies involving about 10 million people found that increasing UPF consumption by 10% raised the risk of developing or dying from various health conditions.
Higher intake of ultraprocessed foods was associated with about a 50% higher risk of cardiovascular disease-related death and common mental disorders.
Researchers also found evidence linking higher UPF intake to a 55% increased risk of obesity, 41% higher risk of sleep disorders, 40% higher risk of type 2 diabetes and a 20% higher risk of depression.
The new study, published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, involved more than 2,100 Australians aged between 40 and 70 who recorded their diets over the past year.
Participants also underwent cognitive testing to assess attention and processing speed. None had dementia at the start of the study.
“For every 10% increase in ultraprocessed food a person consumed, we saw a measurable drop in their ability to focus,” Cardoso said. “This translated to lower scores on standardised cognitive tests measuring visual attention and processing speed.”
Attention is critical for functions such as learning and problem-solving. While no direct link to memory was found, the study estimated overall mental decline using a validated tool that predicts long-term dementia risk.
Each 10% increase in daily UPF consumption was linked to a rise in dementia risk score. A typical diet including ultraprocessed pancakes, chips, cookies and pizza could quickly increase overall intake.
Reducing ultraprocessed foods may help lower risk, especially when done earlier in life.
“Midlife offers a key opportunity to address risk factors before brain changes associated with dementia begin,” Cardoso said.
Ultraprocessed foods have also been linked to negative changes in the endocrine system and gut microbiota, which may affect brain health. They are further associated with conditions such as diabetes, hypertension, obesity and high LDL cholesterol, all of which are known risk factors for dementia.