Advertisement
Editor’s note: Sign up for CNN’s Eat, But Better: Mediterranean Style. Our eight-part guide will show you a delicious, expert-backed eating style that will boost your health for a lifetime.
CNN
—
We all eat them – ultra-processed foods such as Frozen pizza and ready meals make our busy lives much easier. Plus, they’re just plain damn delicious — who isn’t prone to hot dogs, sausage, burgers, french fries, soda, cookies, cake, candy, donuts, and ice cream, to name a few?
However, if more than 20% of your daily caloric intake is ultra-processed foods, you may be increasing your risk of cognitive decline, according to a new study found.
This amount would equate to about 400 calories per day on a 2,000 calorie per day diet. A small order of fries for comparison and regular McDonald’s cheeseburger contains total 530 calories.
The part of the brain involved in executive functions — the ability to process information and make decisions — is particularly badly affected, according to the study published Monday in JAMA Neurology.
Men and women in the study who ate the most processed foods had a 25% faster decline in executive function and a 28% faster rate of overall cognitive impairment compared to those who ate the least processed foods.
“Although this is an association study and not designed to prove cause and effect, there are a number or elements that support the notion that some acceleration in cognitive decline can 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 large and the follow-up is extensive. While evidence is lacking, this is robust enough to conclude that highly processed foods are likely bad for our brains.”
However, there was an interesting twist. When overall diet quality was high — meaning the person also ate plenty of unprocessed, whole fruits and vegetables, whole grains, and healthy sources of protein — the association between ultraprocessed foods and cognitive decline disappeared, Katz said.
“Ultra-processed foods affect diet quality, and therefore their concentration in the diet is in most cases an indicator of poor diet quality,” Katz said. “As atypical as it may seem, some of the participants apparently made it. And when diet quality was high, the observed association between ultra-processed foods and brain function weakened.”
The study followed over 10,000 Brazilians for up to 10 years. Just over half of the study participants were women, white or college graduates, while the median age was 51 years.
Cognitive tests that included immediate and delayed word recall, word recognition, and verbal fluency were administered at the beginning and end of the study, and participants were asked about their diet.
“In Brazil, ultra-processed foods account for 25-30% of total calorie intake. We have McDonald’s, Burger King, and we eat a lot of chocolate and white bread. Unfortunately, it is not very different from many other western countries,” co-author Dr. Claudia Suemoto, Assistant Professor in the Department of Geriatrics at the University of São Paulo Faculty of Medicine, to CNN when the study summary was released in August.
“Fifty-eight percent of the calories consumed by US citizens, 56.8 percent of British citizens and 48 percent of Canadians come from ultra-processed foods,” Suemoto said.
Ultra-processed foods are defined, according to the study, as “industrial formulations of food substances (oils, fats, sugars, starches, and protein isolates) that contain little or no whole foods and typically contain flavorings, colors, emulsifiers, and other cosmetic additives.” .
Those in the study who ate the most processed foods were “more likely to be younger, female, white, have higher education and income, were more likely never to have smoked, and were less likely to be current alcohol users,” the study found.
In addition to the effects on cognition, highly processed foods are already known to increase the risk of obesity, cardiovascular problems, diabetes, cancer and shorter lifespans.
“Ultra-processed foods are generally bad for every part of us,” said Katz, president and founder of the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine.
Ultra-processed foods tend to be high in sugar, salt, and fat, all of which promote Inflammation throughout the body, which “poses perhaps the greatest threat to healthy aging in the body and brain,” said Dr. Rudy Tanzi, Professor of Neurology at Harvard Medical School and director of the Genetics and Aging Research Unit at Massachusetts General Hospital in Boston. He was not involved in the study.
“Meanwhile, because they’re great for a quick meal, they also replace eating foods high in plant fiber, which are important for maintaining the health and balance of the trillions of bacteria in your gut microbiome,” Tanzi added, “what especially important is important for brain health and reducing the risk of age-related brain diseases like Alzheimer’s disease.”
How can you prevent this from happening to you? If you include ultra-processed foods in your diet, try to counter them by also eating quality, whole foods like fruits, vegetables, and whole grains.
“The conclusion proposed here is that highly processed foods are indeed an important ‘ingredient,’ but the exposure that should be the focus of public health efforts is overall diet quality,” Katz said.
One easy way to ensure nutritional quality is to cook and prepare your food from scratch, Suemoto said.
“We say we don’t have time, but it really doesn’t take that long,” Suemoto said.
“And it’s worth it because you’re protecting your heart and your brain from dementia or Alzheimer’s.” That’s the take-home message: stop buying things that are super-made.”
