Adherence to a Vegetarian Diet is not Associated With Depression: Results From the National Health and Nutrition Examination Surveys

Abstract

Objective Adherence to vegetarian diets has been associated with physical health benefits, whereas vegetarian mental health is less well documented. We sought to investigate whether adherence to a vegetarian diet was associated with depression in a nationally-representa-tive sample of US adults. Methods We used population-based data from the US National Health and Nutrition Examination Surveys to examine said associa-tions. Depression was assessed using the Patient Health Questionnaire (PHQ-9), vegetarian status was self-reported. Multivariate regression was used to measure the magnitude of associations, controlling for a range of covariables known to be associated with depressive symptoms. Results Our analysis included 9,584 individuals, of which 910 individuals had PHQ-9 scores suggestive of depression. Vegetarian diet was associated with reduced odds of PHQ-9 defined depression (odds ratio [OR]: 0.49 [95% confidence interval {CI}: 0.24–0.98], p=0.047) in a model adjusting for sex, age, ethnicity, income, and marital status. When adjusting for additional factors (educational level, smoking status, serum C-reactive protein, and body mass index) in a second model, the previously observed association was no longer significant (OR: 0.66 [CI: 0.34–1.26], p=0.203). Conclusion Vegetarian diet was not associated with PHQ-9 defined depression in this nationally-representative sample of adults. Additional longitudinal examinations are warranted to evolve the understanding of the role of vegetarian diets in mental health.