Common foods tied to brain problems
Researchers try to find out how
Roughly 60 percent of the calories in the average American diet come from highly processed foods. We’ve known for decades that eating such packaged products — some breakfast cereals, snack bars, frozen meals, and virtually all packaged sweets, among many other things — is linked to unwelcome health outcomes — an increased risk of diabetes, obesity, and even cancer. But more recent studies point to another major downside to these often delicious, always convenient foods: They appear to have a significant impact on our minds, too.
Research from the past 10 or so years has shown the more ultraprocessed foods a person eats, the higher the chances that they feel depressed and anxious. A few studies have suggested a link between eating UPFs and increased risk of cognitive decline.
What’s so insidious about these foods, and how can you avoid the mental fallout?
What qualifies as an ultraprocessed food?
In 2009, Brazilian researchers put food on a four-part scale, from unprocessed and minimally processed (fruits, vegetables, rice, and flour) to processed (oils, butter, sugar, dairy products, some canned foods, and smoked meats and fish) and ultraprocessed. “Ultraprocessed foods include ingredients that are rarely used in homemade recipes — such as high-fructose corn syrup, hydrogenated oils, protein isolates and chemical additives” including colors, artificial flavors, sweeteners, emulsifiers, and preservatives, said Eurídice Martínez Steele, a researcher in food processing at University of Sao Paulo. This classification system is now used widely by nutrition researchers.
UPFs make up a majority of the packaged foods you find in the frozen food aisles at grocery stores and on the menu at fastfood restaurants — 70 percent of the packaged foods sold in the United States are considered ultraprocessed.
What effect do ultraprocessed foods have?
Recent research has demonstrated a link between highly processed foods and low mood. In one 2022 study of over 10,000 adults in the United States, the more UPFs participants ate, the more likely they were to report mild depression or feelings of anxiety. “There was a significant increase in mentally unhealthy days for those eating 60 percent or more of their calories from UPFs,” Dr. Eric M. Hecht, a Florida Atlantic University researcher and the study’s author, said. “This is not proof of causation, but we can say that there seems to be an association.”
New research has also found a connection between high UPF consumption and cognitive decline. A 2022 study that followed nearly 11,000 Brazilian adults over a decade found a correlation between eating ultraprocessed foods and worse cognitive function (the ability to learn, remember, reason, and solve problems). “While we have a natural decline in these abilities with age, we saw that this decline accelerated by 28 percent in people who consume more than 20 percent of their calories from UPFs,” said Natalia Gomes Goncalves, a professor at the University of São Paulo Medical School and the lead author of the study.
It’s possible eating a healthy diet may offset the detrimental effects of ultraprocessed foods. The Brazilian researchers found that following a healthy eating regimen, like the MIND diet — which is rich in whole grains, green leafy vegetables, nuts, berries, fish, chicken, and olive oil — reduced the dementia risk associated with consuming ultraprocessed foods. Those who followed the MIND diet but still ate UPFs “had no association between UPF consumption and cognitive decline,” Goncalves said.