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Ultra-processed foods — think cookies, chips and soda — are tied to cognitive decline and stroke, a new report finds.

The study was published Wednesday in Neurology. Though it doesn’t show that the foods directly cause memory and thinking problems or stroke, it reveals an association.

Ultra-processed foods are low in protein and fiber, and have added sugar, fat and salt. Unprocessed or minimally processed foods include meats such as simple cuts of beef, pork and chicken, and vegetables and fruits.

“While a healthy diet is important in maintaining brain health among older adults, the most important dietary choices for your brain remain unclear,” W. Taylor Kimberly, MD, PhD, of Massachusetts General Hospital in Boston, said in a statement. “We found that increased consumption of ultra-processed foods was associated with a higher risk of both stroke and cognitive impairment, and the association between ultra-processed foods and stroke was greater among Black participants.”

The researchers evaluated 30,239 people over the age of 45 and followed them over an average of 11 years. The people filled out questionnaires about what they ate and drank. Then the researchers calculated grams of ultra-processed foods and compared them to other foods. The people had no history of cognitive decline or stroke. At the end of the study, 768 people had cognitive impairment and 1,108 had strokes.

Of those with cognitive problems, ultra-processed foods made up 25.8% of their diets compared to 24.6% for those who did not develop cognitive decline. After adjusting for factors such as age, sex, high blood pressure and others that could affect risk of dementia, researchers found that a 10% increase in the amount of ultra-processed foods eaten and associated that with a 16% higher risk of cognitive impairment. Eating more unprocessed or minimally processed foods was linked with a 12% lower risk of cognitive impairment, the researchers noted.

People who had strokes during the study consumed 25.4% of their diet from ultra-processed foods. That compared to 25.1% in those who didn’t have strokes. After adjustments, researchers found greater intake of ultra-processed foods was linked to an 8% increase in risk of stroke, while greater intake of unprocessed or minimally processed foods was tied to a 9% lower risk of stroke.

The effect of ultra-processed food consumption on stroke risk was greater among Black participants, with a 15% relative increase in risk of stroke.

“Our findings show that the degree of food processing plays an important role in overall brain health,” Kimberly said. “More research is needed to confirm these results and to better understand which food or processing components contribute most to these effects.”