by A diet with more ultra-processed foods, such as prepackaged meals, deli, potato chips, sodas, and sweetened breakfast cereals, is associated with an increased risk of cognitive decline and stroke, new research has found.
For the study, scientists examined approximately ten years of data on eating habits, cognitive function, and stroke for approximately 30,000 adults beginning in their mid-sixties. None of the participants had a history of cognitive impairment at the start of the study. By the end of follow-up, 1,108 people had had a stroke and 768 had developed cognitive impairment.
At the same time, people who ate the most unprocessed or lightly processed foods had a 9 percent lower risk of stroke.
“Our study provides reason to be mindful of the food we eat,” says senior study author W. Taylor Kimberly, MD, PhD, associate professor at Harvard Medical School and chief of neurocritical care at Massachusetts General Hospital in Boston. . “Not only should we aim to increase the amount of healthy foods, such as green leafy vegetables, nuts, and fish-based protein, but we should also aim to increase the amount of pre-packaged foods and sugary snacks and reduce fats.”
Small Changes in Ultra-Processed Food Consumption
The study also found that small changes in diet can make a significant difference to brain health.
Each 10 percent increase in the amount of unprocessed and minimally processed foods participants ate was associated with a 12 percent lower risk of accelerated cognitive decline. And every 10 percent increase in consumption of ultra-processed foods was associated with a 16 percent higher risk of accelerated cognitive decline.
The negative impact of ultra-processed foods and the benefits of unprocessed or minimally processed foods persisted even when people followed diets known to promote brain health such as the Mediterranean diet, the DASH diet, or the MIND diet, according to the study. All of these diets encourage eating more plant-based meals, fruits, vegetables, whole grains, beans and nuts and recommend limiting the intake of ultra-processed foods, red meat, and sugary foods and drinks.
In general, ultra-processed foods tend to be the most processed packaged products available in the grocery store. These are usually industrial foods made almost entirely of substances extracted from things like oils, fats, sugars, starches, and proteins, or synthesized in laboratories and factories with few, if any, ingredients that come directly from sources natural plants or animals.
Take potatoes. The whole potato you buy in the produce aisle is not processed at all, and canned potatoes are least of all processed. But potato chips and frozen hash browns are ultra-processed.
Why Ultra-Processed Foods May Be Bad for Brain Health
The study was not designed to prove whether or how ultra-processed foods could or could not directly cause cognitive decline or stroke but only looked for an association.
But researchers have theories as to why ultra-processed food may be at risk for cognitive function. Substances used to process foods and give them a long shelf life may be bad for the brain, says Glen Finney, MD, professor and director of the memory and cognition program at Geisinger Health in Wilkes-Barre, Pennsylvania.
“Chemicals and other substances are often added to ultra-processed foods that differ from what we eat in traditionally prepared foods, some of which may have brain health risks,” says Dr. Finney, who was not involved. the new study. “It’s still something we need to know more about.”
Moreover, ultra-processed foods tend to provide a lot of calories from unhealthy ingredients, says Yu Chen, MPH, PhD, a professor of epidemiology at New York University’s Grossman School of Medicine in Manhattan who was not involved in the new study.
“These foods contain added ingredients such as sugar, salt, fat, artificial colors, and preservatives, as well as substances extracted from foods such as fats and starches,” says Dr. Chen. “Components like fat can stimulate inflammation, which can lead to vascular dysfunction and affect cognitive functions.”
What’s the Best Way to Eat for a Healthy Brain?
To promote brain health over time, people should limit ultra-processed foods as much as possible and try to incorporate as many whole foods as possible, says Andrew Budson, MD, professor of neuroscience at Boston University and coauthor of Seven Steps to Managing Your Aging Memory.
“Don’t eat processed foods, including chips, industrial breads and pastries, packaged sweets and candy, sugar and diet soda, instant noodles and soups, ready-to-eat meals and frozen dinners, and processed meats such as hot dogs. and bologna,” says Budson, who was not involved in the new study.
“Eat unprocessed or minimally processed foods, which include fish, olive oil, avocados, whole fruits and vegetables, nuts and beans, and whole grains—when combined with a healthy Mediterranean menu,” he says.
