Ultra-processed foods: increased risk of depression and anxiety

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Research shows ultra-processed foods increase the risk of developing depression and anxiety. (Photo credit: Gadiel Lazcano/Unsplash)

Ultra-processed foods increase the risk of developing depression and anxiety, according to a growing body of scientific evidence. This is especially true of artificially sweetened sodas and beverages.

Researchers say the consumption of ultra-processed food may indirectly promote depression through several mechanisms, including nutrient deficiencies, inflammation, and an imbalance of the gut microbiota, along with blood-sugar fluctuations and food chemicals.

Ultra-processed foods are industrially formulated with added sugars, salt, carbohydrates, fats, and/or additives. Sweeteners –  including high-fructose corn syrup, sucralose, and aspartame – are commonly found in ultra-processed food. 

UPFs have become a staple in the American diet. Today, about 57% of the calories American adults consume comes from UPFs. That percentage rises to 67% in American children. 

What is the evidence linking ultra-processed foods with depression and anxiety?

A prospective study published in the journal JAMA Network Open in 2023 examined the self-reported diet and mental health of more than 30,000 middle-aged women between 2003 and 2017. All women were free of depression at the beginning of the study. After adjusting for lifestyle factors and comorbidities, the researchers found that, when compared with participants who ate the least ultra-processed food, those who ate the most had an increased risk of depression. Interestingly, when comparing the groups who ate the least and most amounts of UPFs, “only artificially sweetened beverages and artificial sweeteners were associated with greater risk of depression.”

In a 2024 cohort study and systematic review published in Clinical Nutrition, Brazilian researchers examined the prospective association between depressive symptoms and the consumption of ultra-processed food. In the original research, the scientists examined the data of more than 15,000 people who were free of depressive symptoms and/or depression at baseline. Food questionnaires were used to assess study participants’ diet. After a mean follow up of 18.3 months, researchers found that “each 10% increase in the dietary share of ultra-processed foods was associated with a 10% increase in the hazard of incident cases of depressive symptoms.”

In a systematic review published in Nutritional Neuroscience in 2022, researchers investigated the link between ultra-processed food and mood disorders. The results included data from more than 260,000 people from 12 countries. Results showed that UPF consumption was associated with an “enhanced depressive mental health status risk.” The researchers wrote: “For every 10% increase in UPF consumption per daily calorie intake, 11% higher risk of depression was observed among adults.” 

In an umbrella review of 39 meta-analyses published in Clinical Nutrition in 2024, researchers examined the associations between ultra-processed food consumption and several adverse health outcomes. The study authors wrote: “Our updated meta-analysis found a significant association between UPF consumption and depression. A possible mechanistic basis might lie in the macro nutritional characteristics of UPFs (rich in saturated fats and sugar, and low in dietary fiber, micronutrients, and phytochemicals) that may influence a variety of interacting pathways, including inflammation, and oxidative stress. Non-nutritive ingredients used in industrial processing, such as aspartame might also add to the problem as this artificial sweetener was shown to inhibit the synthesis and release of neurotransmitters, dopamine, norepinephrine, and serotonin, which are important in the development of depression.”

A 2022 systematic review and meta-analysis published in Nutrients sought to synthesize the association between “ultra-processed food consumption and depression as well as other mental disorders.” Seventeen studies with a total of more than 380,000 participants were included in the analysis. Researchers found: “Greater ultra-processed food consumption was cross-sectionally associated with increased odds of depressive and anxiety symptoms, both when these outcomes were assessed together as well as separately. Furthermore, a meta-analysis of prospective studies demonstrated that greater ultra-processed food intake was associated with increased risk of subsequent depression.”

In a 2024 systematic umbrella review published in BMJ, researchers examined ultra-processed food consumption and various adverse health effects. The review included 45 analyses. Among the findings were associations between all-cause mortality, obesity, and Type 2 diabetes. The findings also showed increased risk of anxiety and depressive symptoms. The researchers wrote: “We observed … associations in separate assessments of prevalent combined common mental disorder outcomes across six cross sectional designs and incident depressive outcomes across two cohorts.” They concluded:  “These findings provide a rationale to develop and evaluate the effectiveness of using population based and public health measures to target and reduce dietary exposure to ultra-processed foods for improved human health.”

Using data of more than 26,000 people from the NutriNet-Santé cohort in France, researchers investigated the link between diet and symptoms of depression. At baseline no participants showed depressive symptoms. The prospective study, which was published in BMC Medicine, found that, in a mean follow-up of 5.4 years, “a positive association between the %UPF in the overall diet and the risk of incident depressive symptoms.” 

A population-based cohort study published in Food & Function in 2023 found that ultra-processed foods were linked to anxiety and depression. The research, which included self-reported data from more than 180,000 people, found that participants who ate the highest amounts of ultra-processed food had a higher risk of anxiety when compared to those who ate the least amount of UPFs.  

Published in the journal Nutrients, research examined the link between ultra-processed food consumption and symptoms of depression in Italian young adults. The cross-sectional study, which was published in 2023, included nearly 600 people ages 18 to 32. After adjusting for confounding factors, researchers found that “the highest quartile of UPF consumption had higher odds of having depressive symptoms in the energy-adjusted model …. and became even stronger after further adjustment for adherence to the Mediterranean diet as a proxy of diet quality.” 

For a 2023 study published in the Journal of Affective Disorders, researchers used data from participants’ diet, along with clinical and brain imaging data, to examine the link between ultra-processed foods (UPFs), depression, and gray matter volumes in the brain. The researchers examined the diet and depressive symptoms reported by 152 adult study participants, who also underwent magnetic resonance imaging (MRI). The researchers found that “high UPF consumption was associated with higher depressive symptoms in all participants and in those with obesity. Higher consumption was also associated with lower volumes in the posterior cingulate cortex and the left amygdala, which in the participants with obesity also encompassed the left ventral putamen and the dorsal frontal cortex.” The researchers concluded: “UPF consumption is associated with depressive symptoms and lower volumes within the mesocorticolimbic brain network implicated in reward processes and conflict monitoring.”

In a longitudinal study published in the Journal of Affective Disorders in 2023, researchers examined the link between ultra-processed food intake and depression in more than 2,500 Brazilian adults. Researchers collected data from a questionnaire and baseline and then a follow-up questionnaire after a mean of 2.96 years. The researchers found that “participants in the highest quartile of UPF consumption had a higher risk of developing depression than those in the lowest quartile after adjusting for potential confounders.”

“Few studies have tested longitudinal associations between ultra-processed food consumption and depressive outcomes,” researchers began their study published in the Journal of Affective Disorders. In the study, which was published in 2023, researchers examined self-reported data from more than 23,000 participants in the Melbourne Collaborative Cohort Study. After adjusting for lifestyle and socioeconomic factors, the scientists found that the “higher ultra-processed food intake at baseline was associated with subsequent elevated psychological distress as an indicator of depression at follow-up.”

In a 2023 survey published in the journal Nutrients, researchers examined the data of nearly 10,000 Korean adults to assess the link between ultra-processed food and depression. The study was the first to assess the link between UPF consumption and depression in an Asian country’s general population. They found that “in a sex-specific stratification, only females demonstrated a significant association, even after adjusting for confounders. Our findings revealed a significant association between higher UPF intake and depression among females but not among males in the Korean general population.”

In a 2020 comparative study published in the American Journal of Psychiatry, researchers compared diets and their links to depression and anxiety. Using self-reported data from more than 1,000 women, the study authors found that a “traditional” diet of whole foods rich in fruit, vegetables, meat, fish was associated with lower rates of depression and anxiety. Those who ate a “Western” diet, which was considered high in sugar, and processed and fried foods, were at greater risk of depression and anxiety.

In a cross-sectional study published in Public Health Nutrition in 2022, researchers examined the self-reported data of more than 10,000 American adults. After adjusting for socio-demographics, lifestyle factors and comorbidities, the researchers found that “individuals with the highest level of ultra-processed food consumption were significantly more likely to report at least mild depression, more mentally unhealthy and more anxious days per month. They were also significantly less likely to report zero mentally unhealthy or anxious days.”

Food additives and depression

Aspartame is a common sweetener found in ultra-processed foods, particularly diet soft drinks. A 2022 study in the Proceedings of the National Academy of Sciences found that exposure of mice to aspartame at doses equivalent to below 15% of the FDA recommended daily intake for humans produces anxiety-like behavior. The anxiety appears in up to two generations descending from the aspartame-exposed males. “These data do not merely add anxiety to the long list of aspartame’s adverse effects, but also raise the previously unrecognized possibility that aspartame’s adverse effects are not limited to the individuals who consume it but persist for generations to come,” the researchers wrote. “Extrapolation of the findings to humans suggests that aspartame consumption at doses below the FDA recommended maximum daily intake may produce neurobehavioral changes in aspartame-consuming individuals and their descendants.” They concluded: Therefore, aspartame deserves a place on the list of environmental agents such as hormones, insecticides, and drugs of abuse whose adverse effects are not limited to the exposed individuals but manifest in multiple generations of descendants.”

Ultra-processed foods often contain artificial additives and preservatives, along with industry-made sweeteners, like aspartame and sucralose. In a prospective study published in JAMA Network Open in 2023, researchers wrote: “Although the mechanism associating UPF to depression is unknown, recent experimental data suggests that artificial sweeteners elicit purinergic transmission in the brain, which may be involved in the etiopathogenesis of depression.”

What is depression?

Depression is a common but complex and multifaceted disorder that can include low mood, feelings of persistent sadness, and a loss of interest in things a person typically enjoys. Other symptoms can include feelings of hopelessness, difficulty concentrating, irritability, changes in sleep patterns, fatigue, and thoughts of death or suicide. It is a leading cause of disability throughout the world. The disorder affects nearly 280 million, or 5%, of people worldwide, according to the World Health Organization. This estimate is likely to be inaccurately low, because many people who experience depression do not seek help or receive treatment. 

What is anxiety?

While everyone once in a while experiences symptoms of nervousness, worry, and fear, anxiety disorders are mental health conditions characterized by significant feelings of distress that can hinder daily activities. Common types of anxiety disorders include generalized anxiety disorder (GAD), social anxiety disorder, panic disorder, and specific phobias. Symptoms of anxiety disorders can vary widely but may include excessive worrying, restlessness, irritability, muscle tension, feelings of panic or doom, and difficulty concentrating or sleeping. According to the World Health Organization, anxiety is one of the most common mental health disorders, with nearly 301 million people around the world affected by the condition in 2019.

Journalism and opinion

The New Science on What Ultra-Processed Food Does to Your Brain, by Andrea Petersen, Wall Street Journal, March 11, 2024

How ultra-processed food harms the body and brain, by Janis Jibrin, National Geographic, Feb. 29, 2024

The Link Between Highly Processed Food and Brain Health, by Sally Wadyka, New York Times, May 4, 2023

Ultraprocessed foods may raise depressions risks, by Maureen Salamon, Harvard Mind & Mood, Jan. 1, 2024

Artificially sweetened ultraprocessed food linked to depression in women, study finds, by Sandee LaMotte, CNN, Sept. 20, 2023 

What Are Ultra-Processed Food? Can They Affect Your Mental Health? By Carla Delgado, Discover Magazine, Nov. 8, 2023  

Adverse Effects of Ultra-Processed Foods on Mental Health, by Ed Ergenzinger J.D., Ph.D., Psychology Today, Sept. 12, 2022

Read our other fact sheets on the studies that link ultra-processed foods to other severe health risks, including cardiovascular disease, dementia, Type 2 diabetes, addiction, cancer, obesity, and premature death. Also see our fact sheets on the health risks of sucralose and aspartame.

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