People who consume high amounts of highly processed foods report significantly more adverse mental health symptoms, according to new research published in Public Health Nutrition.
Highly processed foods are mostly made up of manufactured ingredients that have been extracted from food and usually contain flavorings, colorings and other additives. Highly processed foods are often high in sugar, fat and salt and often lack important nutrients such as fiber and vitamins. A number of studies have found that highly processed foods can have negative consequences for physical health, but less is known about the relationship between these nutrients and mental health outcomes.
“I’m a chronic disease epidemiologist, and as such I’m interested in a variety of different hypothetical diseases that cause exposures and various health outcomes,” explained study author Eric Hecht, a physician and assistant professor at Florida Atlantic University and the University of Miami. . “Highly processed foods are of enormous interest in a variety of health outcomes, including obesity and inflammatory diseases.”
“Other studies have also investigated the relationship between diet and mental health, but few have examined the relationship between UPF consumption and mental health. Anecdotally, I have often wondered about the link between junk food and subsequent behavioral problems in children and symptoms of anxiety and depression in adults. All of these ideas kind of led to this study.”
For their study, researchers looked at mild depression, the number of mentally unhealthy days, and the number of anxious days in 10,359 adults aged 18 and older from the US National Health and Nutrition Examination Survey, a series of nationally representative surveys that include interviews and physical examinations. Importantly, surveys collect information about eating behaviors and mental health.
Hecht and colleagues found evidence that eating highly processed foods was associated with worse mental health outcomes. People who ate the most highly processed foods tended to have increased symptoms of mild depression along with more “mentally unhealthy days” and “stressful days” in the past month compared to those who ate the least.
“We found a dose-response relationship between UPF consumption and mental health symptoms,” Hecht told PsyPost. “Others have found a link between eating whole foods and improving mental health symptoms. The average American consumes 60% of their calories in the form of UPF. For many other health reasons, this is a bad idea. And now it appears that UPF consumption may be linked to worse mental health. I think in general the average person should look at how much packaged food they eat and make an effort to make the majority of their calorie intake real, unprocessed food.”
A significant number of people who reported that highly processed foods accounted for less than 19% of their daily caloric intake had zero mentally unhealthy days and zero stressful days. “I was struck by the fact that people who consume a diet with less UPF generally describe their last 30 days as free of mental health symptoms,” Hecht said.
The researchers controlled for potentially confounding variables such as age, BMI, race/ethnicity, poverty status, smoking status, and physical activity level. But the study, like all research, comes with some caveats.
“Our study was cross-sectional, so we can’t be sure which came first, the UPF or the symptoms,” Hecht explained. “Reverse causality, meaning that mental health symptoms may increase UPF consumption is a real possibility. However, they are countered by longitudinal studies that have found a temporal relationship between junk food consumption and mental health symptoms. In addition, experimental studies have found that reducing junk food intake improves mental health symptoms compared to people who continue their poor diet.”
“The relationship between UPF consumption and obesity and the relationship between UPF consumption and inflammation also suggest pathways to mental health symptoms, as both excess weight gain and inflammation can lead to mental health symptoms as found in other studies,” the researcher added.
The study, “A Cross-Sectional Examination of Highly Processed Food Consumption and Adverse Mental Health Symptoms,” was authored by Eric M Hecht, Anna Rabil, Euridice Martinez Steele, Gary A. Abrams, Deanna Ware, David C. Landy, and Charles H. Hennekens .