Eating more highly processed foods, such as soda, chips and cookies, may be linked to increased memory problems and strokes, according to a study published in the online issue of the Journal of the American Academy of Neurology, Neurology.

The researchers followed 30,239 people aged 45 and over for about eleven years. Participants filled out questionnaires about what they ate and drank, and the researchers determined how much ultra-processed food they consumed by calculating grams per day to create a percentage of their daily intake. This percentage was calculated across four food groups, ranging from the least processed foods to the most processed foods.

Of the total participants, the researchers examined 14,175 participants for cognitive decline and 20,243 participants for stroke. Both groups had no history of these diseases. By the end of the study, 768 people were diagnosed with cognitive impairment and 1,108 had suffered a stroke.

It found that a 10% increase in the amount of highly processed foods consumed was associated with a 16% higher risk of cognitive impairment, while eating more unprocessed or minimally processed foods was associated with a 12% lower risk of cognitive impairment.

Additionally, higher intake of highly processed foods was associated with an 8% increased risk of stroke, while higher intake of unprocessed or minimally processed foods was associated with a 9% reduced risk of stroke.

The researchers clarify that the study does not prove that eating highly processed foods causes memory and thinking problems or stroke, but it does show an association. “More research is needed to confirm these results and to better understand which food or processing components contribute most to these effects,” explains the study’s lead author, Massachusetts General Hospital neurologist Taylor Kimberly.