There is increasing evidence indicating that diet may influence risk of depression. Ultraprocessed foods — typically calorie-rich, nutrient-poor packaged foods containing added ingredients such as sugar, salt, fat, artificial colors and sweeteners, and preservatives — have been associated with increased risk for obesity, hypertension, high cholesterol levels, and type 2 diabetes. In a recent interview with PBS NewsHour, Olivia Okereke, MD, MS, Director of Geriatric Psychiatry at Mass General discusses the connection between the consumption of ultraprocessed foods (UPF) and increased risk for depression.
Dr. Okereke reviews data from the Nurses’ Health Study II published in JAMA Network Open. This study, conducted between 2003 and 2017, prospectively followed a group of middle-aged females. Diet was assessed using validated food frequency questionnaires every 4 years.
The analysis focused on women who were free of depression at baseline and identified new cases of depression in this cohort, using two definitions for depression. A strict definition required self-reported clinician–diagnosed depression and regular use of an antidepressant, whereas a broader definition required clinical diagnosis and/or use of an antidepressant.
The cohort included 31,712 females, aged 42 to 62 years at baseline (mean 52 [SD 4.7] years; 95.2% non-Hispanic White females). Participants with high UPF intake had greater body mass index (BMI), higher rates of smoking, and increased prevalence of medical comorbidities, such as diabetes, hypertension, and dyslipidemia and were less likely to exercise regularly.
The study identified 2122 incident or new cases of depression using the strict definition and 4840 incident cases using the broader definition. Compared with those with the lowest UPF consumption (in the lowest quintile), those with the highest UPF consumption
highest quintile had an increased risk of depression, using both the strict definition (hazards ratio or HR, 1.49; 95% CI, 1.26-1.76; P < .001) and the broader definition (HR, 1.34; 95% CI, 1.20-1.50; P < .001). The results were not altered after inclusion of potential confounders.
Looking at specific food types and risk for depression, the researchers observed that the greatest risk was associated with artificial sweeteners and artificially sweetened beverages.
Diet as a Modifiable Risk Factor for Depression
The findings of this study suggest that greater consumption of ultraprocessed foods, particularly artificial sweeteners and artificially sweetened beverages, is associated with increased risk of depression. One of the strengths of this study is that it was large and was able to consider potential confounding factors, including exercise and smoking.
Exactly how UPF may contribute to increased risk for depression is not yet clear. Processed and ultraprocessed foods are thought to increase inflammation, a factor associated with depression. UPF may also contribute to metabolic changes that increase vulnerability to depression. Others point to the gut microbiome, stating that ultraprocessed foods may alter the composition of the gut microbiome which may have downstream effects on brain health and risk of depression.
Future studies are needed to better understand the link between ultraprocessed foods and risk for depression. In addition, the researchers also highlight the need to conduct similar studies in more diverse populations.
Other contributors to this study included Chatpol Samuthpongtorn, MD, Long H. Nguyen, MD, MS, Dong D. Wang, ScD, MD, Mingyang Song, MD, ScD, Andrew T. Chan, MD, MPH and Raaj S. Mehta, MD, MPH.
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Samuthpongtorn C, Nguyen LH, Okereke OI, Wang DD, Song M, Chan AT, Mehta RS. Consumption of Ultraprocessed Food and Risk of Depression. JAMA Netw Open. 2023 Sep 5; 6(9):e2334770.
