Ultra-processed foods linked to increased dementia risk

In the United States, ultra-processed foods (UPFs) make up roughly 53% of all calories consumed by adults and almost 62% of all calories consumed by children. However, research suggests having a diet high in UPFs can increase the risk of several health conditions, including obesity, sleep disorders, type 2 diabetes, cardiovascular disease, and depression.

In a new study published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, researchers from Australia analyzed data from 2,192 participants between the ages of 40 and 70 to determine if their diets impacted their cognitive function. Participants completed a food questionnaire and four cognitive function tests assessing their attention and memory.

On average, UPFs made up roughly 41% of participants' total caloric intake, though the proportion was significantly higher among younger participants and men.

Overall, the researchers found that for every 10% increase in UPFs in a person's diet, there was a 0.24-point increase in dementia risk. There was also a "measurable drop in attention, even when people had otherwise healthy diets," the researchers wrote.

"To put our findings in perspective, a 10 percent increase in ultra-processed foods is roughly equivalent to adding a standard packet of chips to your daily diet," said Barbara Cardoso, a senior lecturer of nutrition dietetics and food at Monash University in Australia and the study's lead author. "In clinical terms, this translated to consistently lower scores on standardized cognitive tests measuring visual attention and processing speed."

According to the researchers, the 10% increase was considered "baseline," and eating even more UPFs could further increase the risk of dementia. They also found evidence associating higher UPF consumption with a roughly 50% increased risk of cardiovascular disease-related death and common mental disorders.

What to eat to reduce your dementia risk

Although high UPF consumption has been linked to dementia, Kimberly said a "silver lining" is that people can reduce their risk by lowering their UPF intake over time. In his study, Kimberly found that replacing UPFs with more minimally processed and whole foods over a five- to six-year period led to a 12% lower risk of cognitive decline.

A separate study also found adults in their 50s and 60s who cut out many unhealthy foods from their diets over a decade had an 11% lower risk of dementia and Alzheimer's disease compared to those who didn't change their diets. 

There are also different diets and foods associated with a reduced risk of dementia.

For example, the Mediterranean diet has been associated with a reduced risk of cancer, diabetes, heart disease, stroke, and dementia, especially for people who have two copies of the APOE4 gene, a risk factor for Alzheimer's disease. The diet focuses on whole grains, fruits and vegetables, beans, seeds, nuts, and extra-virgin olive oil.

Previous studies have also found similar links between egg consumption and Alzheimer's risk. In all these studies, researchers found that the nutritional components of eggs, including choline, lutein, tryptophan, and docosahexaenoic acid (DHA), all helped preserve cognitive function.

"These nutrients may act synergistically to support cognitive resilience and mitigate neurodegenerative processes," the researchers of the Journal of Nutrition study wrote. "Notably, deficiencies in choline and DHA have been documented in the brains of individuals with Alzheimer's disease."

Daniel Amen, a psychiatrist and founder of Amen Clinics, noted that diet has a "powerful impact" on the brain, calling it an "energy-hungry organ."

The brain "uses about 20% of the calories you consume, so the quality of those calories matter," he said, recommending that people "[b]uild meals around colorful vegetables and fruits, clean protein, healthy fats, nuts, seeds, and high-fiber carbohydrates. Start by replacing one ultra-processed food per day with a brain-healthy option."

"Remember, you're not stuck with the brain you have," Amen added. "You can make it better, and it starts with the next bite."