We all eat them — ultraprocessed foods such as frozen pizza and ready-to-eat meals make our busy lives much easier. Besides, they are just darn tasty — who isn’t susceptible to hot dogs, sausages, burgers, french fries, sodas, cookies, cakes, candy, doughnuts and ice cream, to name just a few?
If more than 20% of your daily calorie intake is ultraprocessed foods, however, you may be raising your risk for cognitive decline, a new study found.
That amount would equal about 400 calories a day in a 2,000-calories-a-day diet. For comparison, a small order of fries and regular cheeseburger from McDonald’s contains a total of 530 calories.
The part of the brain involved in executive functioning — the ability to process information and make decisions — is especially hard hit, according to the study published Monday in JAMA Neurology.
In fact, men and women who ate the most ultraprocessed foods had a 28% faster rate of global cognitive decline and a 25% faster rate of executive function decline compared with people who ate the least amount of overly processed food, the study found.
“While this is a study of association, not designed to prove cause and effect, there are a number or elements to fortify the proposition that some acceleration in cognitive decay may be attributed to ultraprocessed foods,” said Dr. David Katz, a specialist in preventive and lifestyle medicine and nutrition, who was not involved in the study.
“The sample size is substantial, and the follow-up extensive. While short of proof, this is robust enough that we should conclude ultraprocessed foods are probably bad for our brains.”
There was an interesting twist, however. If the quality of the overall diet was high — meaning the person also ate a lot of unprocessed, whole fruits and veggies, whole grains and healthy sources of protein — the association between ultraprocessed foods and cognitive decline disappeared, Katz said.
“Ultraprocessed foods drag diet quality down, and thus their concentration in the diet is an indicator of poor diet quality in most cases,” Katz said. “Atypical as it seems, apparently some of the participants managed it. And when diet quality was high, the observed association between ultraprocessed foods and brain function abated.”
It’s not a lot of calories
The study, presented Monday at the 2022 Alzheimer’s Association International Conference in San Diego, followed over 10,000 Brazilians for up to 10 years. Just over half of the study participants were women, White or college educated, while the average age was 51.
Cognitive testing, which included immediate and delayed word recall, word recognition and verbal fluency were performed at the beginning and end of the study, and participants were asked about their diet.
Burger King and we eat a lot of chocolate and white bread. It’s not very different, unfortunately, from many other Western countries,” said coauthor Dr. Claudia Suemoto, an assistant professor in the division of geriatrics at the University of São Paulo Medical School.
“Fifty-eight percent of the calories consumed by United States citizens, 56.8% of the calories consumed by British citizens, and 48% of the calories consumed by Canadians come from ultraprocessed foods,” Suemoto said.
