Highly Processed Foods Linked to Accelerated Cognitive Decline
Adults who consume the most processed food may experience a much faster decline in memory and executive function.
Too many daily calories from highly processed foods like lunch meats, frozen dinners, and packaged cookies may speed up cognitive decline, a new study suggests.
In the study, researchers examined the diets and cognitive function test results of more than 8,000 adults in Brazil. At the start of the study, participants consumed an average of about 2,850 calories a day. About 28 percent of their daily calories came from highly processed foods.
After about nine years of follow-up, cognitive test scores for memory and executive function declined the most for participants who ate the most highly processed foods, according to preliminary study results presented at the Alzheimer’s Association International Conference held July 31–August 4 in San Diego.
“There is growing evidence that what we eat can impact our brains as we age, and many studies suggest it is best for our brain to eat a heart-healthy, balanced diet low in processed foods and high in whole, nutritional foods like vegetables and fruits,” says Percy Griffin, PhD, the director of scientific engagement at the Alzheimer’s Association.
“It's troubling but not surprising to see new data suggesting these foods can significantly accelerate cognitive decline,” says Dr. Griffin, who wasn’t involved in the new study.
According to Harvard Health Publishing, highly processed foods tend to be chock-full of added sugar, salt, fat, and artificial preservatives. During manufacturing, many nutrients found in unprocessed whole foods get altered or removed, leaving products that aren’t as nutritious.
Whole foods and minimally processed foods have fewer ingredients on the label, or no label at all, according to Harvard Health. These are mostly found in the produce aisle — like ears of corn or sacks of potatoes. Canned corn or baked potatoes are processed during canning or cooking — but not so much that these products are considered highly processed. Their highly processed counterparts are corn chips and french fries.
The new study results haven’t been published in a medical journal or independently reviewed.
Beyond this, a drawback of the study is that results from Brazilians may not be generalizable to people in other countries. Rice and beans are mealtime staples in Brazil, according to a study in Nutrients from May 2020, along with side servings of meat, vegetables, dairy, bread, and fruits. A typical Western or U.S. diet, per an article in the November–December Missouri Medicine, is full of sugars, fats, red and processed meats, and refined grains.
In the past few years, research has linked highly processed foods to weight gain, heart disease, stroke, certain cancers, and a shorter life span.
This is particularly bad news for Americans. One previous study, published in the BMJ in 2016, found that U.S. adults get about 58 percent of their calories from highly processed foods.
“The good news is there are steps we can take to reduce risk of cognitive decline as we age,” Griffin says.
A heart-healthy lifestyle promotes a healthier brain, too, and helps preserve cognitive function, according to the American Heart Association. Such a lifestyle includes a diet rich in whole grains, fresh fruits and vegetables, and lean protein (and light on highly processed foods) as well as adequate sleep and exercise, no tobacco, and alcohol in moderation.
Taking care of your mental health, maintaining an active social life, and getting regular hearing checkups as you age rounds out the picture of a how to prevent cognitive decline, according to the AHA.
“Even if you begin with one or two healthful actions, you’re moving in the right direction,” Griffin says. “It’s never too early or too late to incorporate these habits into your life.”