Study: Ultraprocessed foods linked to dementia risk and attention decline

A study published in Alzheimer's and Dementia has found something that cuts across the usual dietary wisdom: it doesn't matter how carefully you otherwise eat. Researchers from Monash University in Australia tracked more than 2,000 dementia-free adults between 40 and 70, measuring their diets against their cognitive performance. What they discovered was stark. For every 10 percent increase in ultraprocessed food consumption, attention scores dropped and dementia risk climbed—and this held true even for people who otherwise adhered to healthy eating patterns like the Mediterranean diet.

The study identified ultraprocessed foods as linked to more than 30 adverse health outcomes, including the major dementia risk factors: cardiovascular disease, type 2 diabetes, and obesity. Yet the cognitive finding was distinct. While memory showed no significant correlation with ultraprocessed food intake, attention—the ability to focus, to concentrate, to hold information long enough to act on it—declined measurably. A 10 percent increase in ultraprocessed foods amounts to roughly a pack of chips per day, a seemingly small shift that nonetheless registered as a meaningful drop in cognitive function.

Barbara Cardoso, a nutritional biochemist at Monash and one of the study's authors, told Fox News Digital that the finding surprised her in one crucial way: the Mediterranean diet, long celebrated as a cognitive protector, did not buffer against the harms of ultraprocessed food. This suggested that food processing itself—not just the presence of healthy foods—acts as a distinct driver of cognitive decline. Cardoso emphasized that ultraprocessed foods should be avoided as much as possible, not only because of their links to heart disease and obesity, but because they directly undermine the brain's ability to perform basic tasks like driving safely.

Dr. Daniel Amen, a California psychiatrist and founder of Amen Clinics, framed the mechanism plainly: the brain consumes roughly 20 percent of the calories you take in, making the quality of those calories consequential. Ultraprocessed foods—packaged snacks, soft drinks, ready-made meals laden with sugar, unhealthy fats, additives, and low-quality ingredients—promote inflammation, insulin resistance, poor blood flow, and oxidative stress. All of these damage cognition. Amen noted that attention functions as a gateway to learning, memory, decision-making, and problem-solving. Without focus, information cannot be properly encoded. The foods themselves may carry marketing claims about being sugar-free or keto-friendly, but the processing destroys the natural structure of food and introduces chemicals that appear to affect how the brain works.

The practical advice from experts converged on incremental replacement. Rather than overhauling diet overnight, Amen suggested starting by swapping one ultraprocessed food per day for a brain-healthy alternative: nuts instead of chips, water or unsweetened green tea instead of soda, berries instead of packaged sweets. He emphasized that small choices made consistently can reshape the brain. For those with family histories of dementia, memory concerns, diabetes, high blood pressure, or weight issues, diet is not peripheral—it is a primary intervention for brain health.

Courtney Kloske, director of scientific engagement at the Alzheimer's Association, affirmed that the study's findings align with the organization's long-standing guidance: eat a balanced diet, cut back on processed foods, and adopt the scientifically supported behaviors that protect against age-related cognitive decline. The MIND diet—focused on dark leafy greens, berries, nuts, whole grains, olive oil, and fish, with limited sugar, red meat, and unhealthy fats—showed better cognitive outcomes in the study. Combined with exercise, brain training, and regular health monitoring, dietary choices appear to offer meaningful protection.

One limitation shadowed the findings: the data was self-reported, which can weaken the strength of conclusions. Still, the message from researchers and clinicians was consistent. You are not stuck with the brain you have. The next bite matters. For millions eating ultraprocessed foods daily, the study suggests that small, deliberate changes in what lands on the plate could reshape cognitive capacity in ways both measurable and meaningful.