Ultra‑Processed Foods And Your Brain: What A New National Study Reveals About Dementia Risk

Why This Study Matters

A new study in the American Journal of Public Health followed more than 5,000 older adults across the United States from 2013 to 2020 and asked a simple, powerful question: does eating more ultra‑processed foods change the risk of later cognitive problems or dementia? Ultra‑processed foods are the highly industrial products that dominate modern grocery aisles—think sugary drinks, packaged snacks and sweets, frozen pizzas, and many ready‑to‑eat items that rely on additives to boost flavor, extend shelf life, and cut costs.

As people live longer, dementia and milder forms of cognitive impairment are rising, so understanding how everyday diets shape brain aging has become an urgent public‑health priority. This new analysis adds important evidence that what is on the plate -- especially how processed it is -- may meaningfully influence brain health in later life.

What The Researchers Did

Researchers used data from the Health And Retirement Study, a nationally representative survey of adults aged 50 and older in the United States. In 2013, participants completed a detailed food‑frequency questionnaire that allowed the team to calculate how much of each person’s diet came from ultra‑processed foods versus minimally processed, more “whole” foods.

They then linked those diet data to repeated cognitive testing every two years between 2014 and 2020. The test sorted people into three categories:

• Normal cognition,

• “Cognitive impairment with no dementia” (CIND), and

• Dementia.

People with prior dementia or serious memory problems at baseline, or who developed cognitive impairment very early in follow‑up, were excluded to reduce the chance that pre‑existing brain changes were driving diet choices.

What The Study Found

On average, ultra‑processed foods made up about one‑fifth of total food by weight and more than two‑fifths of total calories in this older U.S. sample. The biggest contributors were sugar‑sweetened beverages, other sweetened beverages, dairy‑based ultra‑processed products, packaged snacks and sweets, and refined grain products.

When the researchers compared people eating the lowest amounts of ultra‑processed foods with those eating the highest amounts (energy‑adjusted grams), those in the highest group had a noticeably higher risk of developing dementia, milder cognitive impairment, and a combined endpoint of either condition over nearly nine years of follow‑up, even after accounting for age, sex, race/ethnicity, education, income, smoking, alcohol, physical activity, depression, chronic disease, and total energy intake.

In contrast, people who ate more unprocessed or minimally processed foods had a lower risk of all three outcomes, suggesting that both limiting ultra‑processed products and emphasizing minimally processed choices may support healthier cognitive aging.

One striking detail is that processed meats—such as certain sausages, bacon, and deli meats—stood out as the ultra‑processed subcategory most consistently linked to higher risk of dementia and cognitive impairment, even when all ultra‑processed subgroups were considered together. The associations did not clearly differ by gender or education level, but there were hints that socially isolated older adults might be more vulnerable to the cognitive risks of higher ultra‑processed intake.

How Ultra‑Processed Foods May Affect The Brain

Ultra‑processed foods often combine high levels of added sugars, unhealthy fats, and sodium, along with low fiber, with a structure that makes them easy to overconsume. Diets built around these products are linked in other research to obesity, type 2 diabetes, cardiovascular disease, and higher mortality—conditions that themselves are known risk factors for cognitive decline and dementia.

The authors also point to experimental and mechanistic work suggesting that ultra‑processed diets may disrupt the gut microbiome, increase inflammation and oxidative stress, and interfere with brain‑related signaling pathways, all of which could contribute to accelerated brain aging. Food additives such as some emulsifiers and non‑nutritive sweeteners have been shown in animal and human studies to alter microbial communities and metabolic processes in ways that might harm long‑term health, though more human data specifically focused on cognition are needed.

What This Means For Us

The BrainSavers approach has always emphasized that the brain and the body are deeply connected: what supports heart and metabolic health tends to support memory, attention, and thinking skills as well. This study reinforces that message by linking higher ultra‑processed food intake to worse cognitive outcomes, and higher minimally processed food intake to better outcomes, in a large, nationally representative group of older adults.

The findings do not mean that an occasional packaged treat will cause dementia. Instead, they suggest that long‑term patterns—what makes up the bulk of daily calories and grams of food—are what matter for protecting brain function over time. For many older adults, ultra‑processed foods are appealing because they are inexpensive, convenient, and heavily marketed; this reality points to the importance of both individual choices and broader policy changes.

Practical BrainSavers Takeaways For Ultra-processed Foods and Dementia Risk

Here are BrainSavers‑aligned, realistic steps inspired by the study’s findings:

• Shift The Balance Toward Minimally Processed Foods. Aim to build most meals around vegetables, fruits, whole grains, beans, nuts, seeds, and minimally processed sources of protein such as fish, poultry, and plain yogurt, which were linked to lower risk of cognitive impairment in this analysis.

• Cut Back On Sugar‑Sweetened And Ultra‑Processed Drinks. Sugary beverages were the single largest contributor to ultra‑processed intake by weight in this cohort; replacing them with water, unsweetened tea, or coffee is a high‑impact, brain‑friendly swap.

• Limit Processed Meats And Heavily Processed Convenience Foods. Because processed meats showed particularly strong associations with dementia and CIND, treating these items as occasional rather than routine can be a targeted way to reduce risk.

• Pair Dietary Changes With Other Brain‑Healthy Habits. The same study adjusted for physical activity, smoking, alcohol use, depression, and chronic conditions—factors that BrainSavers already addresses in its multi‑pillar programs. Continuing to move regularly, stay socially connected, lower your stress, get more restful sleep, and regularly challenge your brain will likely amplify the benefits of dietary improvements.

• Watch For Social Isolation. Because socially isolated participants appeared to show stronger associations between ultra‑processed intake and cognitive impairment, this underscores that loneliness and diet can interact; helping older adults build both social connection and access to minimally processed meals may be especially powerful.

Try This This Week

• Swap at least one sugary drink for water, sparkling water, or unsweetened tea each day.

• Replace one processed meat (like bacon or deli meat) with a less processed option such as beans, eggs, fish, or poultry.

• Add one extra minimally processed food to your plate daily—like a fruit, vegetable, or handful of nuts.