High Consumption of Ultraprocessed Foods Linked to Increased Risk of Depression

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Greater intake of ultraprocessed foods (UPFs), especially artificially sweetened beverages and artificial sweeteners, was associated with increased risk of depression, according to a cohort study of more than 31 000 women published in JAMA Network Open.

Recent research has suggested that diet may influence risk of depression, according to first author Chatpol Samuthpongtorn, MD, postdoctoral researcher, Harvard Medical School, Massachusetts General Hospital, and colleagues. Although UPFs (ie, energy-dense, palatable, and ready-to-eat items) have been previously connected to health outcomes such as mortality, diabetes, and cardiovascular disease, there is limited evidence on associations between depression and UPFs.

“Prior studies have been hampered by short-term dietary data and a limited ability to account for potential confounders,” wrote Samuthpongtorn and coauthors. “Additionally, no study has identified which UPF foods and/or ingredients that may be associated with risk of depression or how the timing of UPF consumption may be associated. Therefore, we investigated the prospective association between UPF and its components with incident depression.”

Investigators conducted a prospective cohort study of 31 712 women (mean age, 52 years; 95.2% non-Hispanic White) aged 42 to 62 years who were enrolled in the Nurses’ Health Study II between 2003 and 2017 and free of depression of baseline.

Every 4 years, the participants’ diet was evaluated using validated food frequency questionnaires. Researchers also estimated UPF intake using the NOVA classification system, “which groups foods according to the degree of their processing.”

“In secondary analyses, we classified UPF into their components, including ultraprocessed grain foods, sweet snacks, ready-to-eat meals, fats and sauces, ultraprocessed dairy products, savory snacks, processed meat, beverages, and artificial sweeteners,” added authors.

Regarding depression, investigators used 2 definitions: “(1) a strict definition requiring self-reported clinician-diagnosed depression and regular antidepressant use and (2) a broad definition requiring clinical diagnosis and/or antidepressant use.”

FINDINGS

Samuthpongtorn and colleagues found that participants with high UPF intake had increased smoking rates, body mass index, prevalence of comorbidities such as hypertension and diabetes, and were less likely to exercise regularly.

Investigators identified 2122 incident cases of depression using the strict definition and 4840 incident cases using the broad definition, according to the study results.

Compared with those in the lowest quintile of UPF intake, participants in the highest quintile had an increased risk of depression—using both the strict definition (hazard ratio [HR] 1.49, 95% CI 1.26-1.76; P<.001) and the broad definition (HR 1.34, 95% CI 1.20-1.50; P<.001).

When researchers examined the association of specific UPF components with risk of depression, they found that only artificial sweetened beverages (HR 1.37, 95% CI 1.19-1.57; P<.001) and artificial sweeteners (HR 1.26, 95% CI 1.10-1.43; P<.001) were associated with greater risk of depression.

In an exploratory analysis, results showed that participants who reduced UPF intake by at least 3 servings per day had a lower risk for depression using the strict definition (HR 0.84, 95% CI 0.71-0.99) compared with those with relatively stable consumption in each 4-year period.

“These findings suggest that greater UPF intake, particularly artificial sweeteners and artificially sweetened beverages, is associated with increased risk of depression,” concluded Samuthpongtorn et al. “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.”

Source: Samuthpongtorn C, Nguyen LH, Okereke OI, et al. Consumption of ultraprocessed food and risk of depression. JAMA Netw Open. 2023;6:e2334770.