Researchers found that people who consumed the highest amounts of ultraprocessed foods had a significantly greater risk of developing dementia.
The study suggests replacing even a portion of ultraprocessed foods with minimally processed alternatives may help lower risk.
Experts say the findings add to growing evidence linking diet quality to long-term brain health.
A new study has found that people who consume large amounts of ultraprocessed foods may face a significantly increased risk of developing dementia, adding to mounting evidence that diet plays a critical role in brain health.
The research, published this week in a peer-reviewed medical journal, tracked thousands of adults over several years and examined the relationship between dietary habits and cognitive decline. Investigators found that participants whose diets contained the highest proportion of ultraprocessed foods were substantially more likely to develop dementia than those who consumed the least.
Ultraprocessed foods include products such as packaged snacks, sugary breakfast cereals, soft drinks, instant noodles, and many ready-to-eat meals. These products often contain additives, preservatives, artificial flavorings, and ingredients not typically used in home cooking.
Researchers said the findings remained significant even after accounting for factors such as age, education, physical activity, smoking, and other health conditions that can influence dementia risk.
The findings
"Our findings suggest that diet quality may be an important and potentially modifiable factor in maintaining cognitive health as people age," the study authors wrote.
The study also found that replacing a portion of ultraprocessed foods with minimally processed alternatives—including fruits, vegetables, whole grains, legumes, and lean proteins—was associated with a lower risk of cognitive decline.
While the study does not prove that ultraprocessed foods directly cause dementia, experts say it strengthens concerns about the long-term health effects of heavily processed diets. Previous research has linked high consumption of ultraprocessed foods to obesity, cardiovascular disease, Type 2 diabetes, and certain cancers.
The role of diet
Neurologists not involved in the study noted that the brain depends on a steady supply of nutrients and that diets high in sugar, unhealthy fats, and sodium may contribute to inflammation and vascular damage that can affect cognitive function over time.
More than 6 million Americans are currently living with Alzheimer's disease and related dementias, according to health officials. As the population ages, researchers continue to investigate lifestyle factors that could help reduce risk.
Experts say the latest findings support existing recommendations to emphasize whole foods and limit heavily processed products as part of an overall healthy diet.