A new study suggests that eating a lot of ultra-processed foods—like soft drinks, chips, and cookies—may increase the risk of stroke and memory problems. The study, published on May 22 in Neurology, found a link between processed food and brain health, but it did not prove that these foods directly cause these health problems.
What Are Ultra-Processed Foods?
Ultra-processed foods are foods that go through multiple industrial processes and contain added sugar, fat, and salt. They often lack important nutrients like protein and fiber. Some examples include:
- Soft drinks and sugary beverages
- Chips and cookies
- Ice cream
- Fast food like hamburgers
- Packaged bread and flavored cereals
- Canned baked beans, ketchup, and mayonnaise
In contrast, unprocessed or minimally processed foods are natural foods with little or no industrial processing. These include fresh meats like beef, pork, and chicken, as well as fruits and vegetables.
Dr. W. Taylor Kimberly of Massachusetts General Hospital, the study’s lead author, explained that while a healthy diet is important for brain health, scientists are still figuring out which specific food choices make the biggest difference.
The Study
Researchers followed 30,239 people aged 45 and older for an average of 11 years. The participants self-identified as Black or white and answered surveys about their diets. Researchers calculated the percentage of their daily food intake that came from ultra-processed foods and divided them into four groups, from those who ate the least to those who ate the most.
The study focused on two groups:
- 14,175 people were tracked for memory and thinking problems (cognitive impairment)
- 20,243 people were tracked for stroke
None of the participants had a history of cognitive issues or stroke at the beginning of the study.
What They Found
By the end of the study:
- 768 people were diagnosed with cognitive impairment (memory and thinking problems)
- 1,108 people had a stroke
People who developed memory problems got about 25.8% of their daily food intake from ultra-processed foods, compared to 24.6% for those who did not develop memory issues. After adjusting for factors like age, sex, and high blood pressure, researchers found that a 10% increase in processed food intake was linked to a 16% higher risk of cognitive impairment.
On the other hand, people who ate more unprocessed or minimally processed foods had a 12% lower risk of cognitive impairment.
For stroke, people who had a stroke ate about 25.4% of their diet from ultra-processed foods, compared to 25.1% for those who did not have a stroke. After adjustments, eating more processed food was linked to an 8% higher risk of stroke, while eating more unprocessed foods was linked to a 9% lower risk.
The effect of processed food on stroke risk was even stronger among Black participants, who had a 15% higher stroke risk when eating more ultra-processed foods.
Why Does This Matter?
The study suggests that how food is processed matters for brain health. People who ate more processed foods had a higher chance of developing memory problems or having a stroke, while those who ate fresher, less processed foods had lower risks.
However, more research is needed to understand why processed foods have this effect. Dr. Kimberly emphasized that scientists need to explore which ingredients in processed foods might be harming brain health.
Limitations of the Study
The study only included participants who identified as Black or white, so the results may not apply to other racial or ethnic groups. Also, since the study only shows a link between processed food and brain health, it does not prove that processed food directly causes stroke or cognitive decline.
Final Thoughts
While researchers continue to study the effects of processed foods, this study supports the idea that eating more whole, unprocessed foods may help protect brain health. Simple dietary changes—such as replacing processed snacks with fresh fruits, vegetables, and lean meats—could be an important step in reducing the risk of memory loss and stroke later in life.
If you care about dementia, please read studies that eating apples and tea could keep dementia at bay, and Olive oil: a daily dose for better brain health.
For more health information, please see recent studies what you eat together may affect your dementia risk, and time-restricted eating: a simple way to fight aging and cancer.
The research findings can be found in Neurology.
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