Journal Article

Plant-based diets especially healthy ones are negatively associated with depression: a cross-sectional study

Zhang, Bao, Li, Meiling, Li, Xiude

2025

Overview

Background Diet was a potentially modifiable factor in the prevention of depression. We aimed to investigate associations of an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI) with the prevalence of depression. We hypothesized that plant-based diets especially the hPDI may be associated with lower depression, whereas uPDI would increase the depression. Methods This is a cross-sectional study using data from the US National Health and Nutrition Examination Survey 2005–2018. Diet was assessed by 24-hour recalls. Depression was measured using the Patient Health Questionnaire-9 (PHQ-9). Odds ratios (ORs) and percentage changes (%) were calculated by logistic regression and linear regression, respectively. Results Among the 31,622 participants aged 20 years or older, the age-standardized prevalence of major depression (PHQ-9 score ≥ 10) was 8.8% ( n  = 2,744). The overall PDI was not associated with odds of depression (OR comparing extreme quintiles 0.84, 95% confidence interval [CI]: 0.66–1.07; p trend =0.168), whereas it was associated with lower PHQ-9 scores in multiple linear regression ( β =-0.07, 95%CI: -0.13, -0.02, p trend =0.045). Participants with higher hPDI scores had lower odds of depression (OR = 0.69, 95%CI: 0.55, 0.87, p trend = 0.007) and lower PHQ-9 scores ( β =-0.07, 95%CI: -0.14, 0.00, p trend = 0.013). Conversely, higher uPDI scores were positively associated with prevalence of depression (OR = 1.78, 95%CI: 1.44–2.20, p trend < 0.001) and PHQ-9 scores ( β  = 0.19, 95%CI: 0.14, 0.24, p trend < 0.001). Conclusions Plant-based diets, especially when they are enriched with healthier plant foods, may be beneficial for primary prevention of depression. However, plant-based diets that emphasize less healthy plant foods are associated with higher depression levels among US adults.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: Adult / Aged / Biostatistics / Cross-Sectional Studies / Depression / Depression - epidemiology / Depression - prevention & control / Depression, Mental / Diet, Plant-Based / Diet, Vegetarian - psychology / Diet, Vegetarian - statistics & numerical data / Environmental Health / Epidemiology / Female / Health aspects / Healthful plant-based diet / Humans / Male / Medicine / Medicine & Public Health / Middle Aged / Nutrition Surveys / Patient health questionnaire-9 / Plant-based diet / Prevalence / Public Health / Risk factors / Statistics / Unhealthful plant-based diet / United States - epidemiology / Vaccine / Vegetarianism / Young Adult