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

Q: What was the study designed to examine?

The study examined whether overall, healthful, and unhealthful plant-based diet indices are associated with the prevalence and severity of depression.

Q: How were diet and depression measured?

Diet was assessed using 24-hour dietary recalls, and depression was measured using the Patient Health Questionnaire-9 (PHQ-9).

Q: What were the main findings regarding hPDI and uPDI?

Higher hPDI scores were associated with lower odds of depression and lower PHQ-9 scores, while higher uPDI scores were positively associated with both depression prevalence and PHQ-9 scores.

Sep 28, 2026

Uploaded by RuangKosong

Diet represents a potentially modifiable factor for preventing depression. This cross-sectional study investigated associations between an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI) with depression prevalence. Data from the US National Health and Nutrition Examination Survey 2005–2018 used 24-hour recalls for diet and PHQ-9 for depression assessment, with odds and percent changes derived from logistic and linear regression models.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Abstract

Background

Methods

Results

Conclusions

Keywords

Introduction

Zhang et al. BMC Public Health (2026) 26:17 BMC Public Health [https://doi.org/10.1186/s12889-025-25748-9](https://doi.org/10.1186/s12889-025-25748-9) RESEARCH Open Access Plant-based diets especially healthy ones are negatively associated with depression: a cross-sectional study Bao Zhang 1†, Meiling Li2† and Xiude Li 1* Abstract 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; ptrend=0.168), whereas it was associated with lower PHQ-9 scores in multiple linear regression (β=-0.07, 95%CI: -0.13, -0.02, ptrend=0.045) . Participants with higher hPDI scores had lower odds of depression (OR = 0.69, 95%CI: 0.55, 0.87, ptrend=0.007) and lower PHQ-9 scores (β=-0.07, 95%CI: -0.14, 0.00, ptrend=0.013). Conversely, higher uPDI scores were positively associated with prevalence of depression (OR = 1.78, 95%CI: 1.44–2.20, ptrend <0.001) and PHQ-9 scores (β = 0.19, 95%CI: 0.14, 0.24, ptrend <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. Keywords Plant-based diet, Depression, Healthful plant-based diet, Unhealthful plant-based diet, Patient health questionnaire-9 †Bao Zhang and Meiling Li contributed equally to this work as cofirst authors. *Correspondence: Xiude Li[xiudeli@foxmail.com](xiudeli@foxmail.com) 1Department of Clinical Nutrition, the First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, Anhui 230022, China 2Department of Nutrition and Food Hygiene, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit [http://creati](http://creati)[vecommons.org/l](vecommons.org/l)icenses/by-nc-nd/4.0/. Introduction Depression is a common mental disorder and the primary cause of disability, impacting an estimated 350 million individuals worldwide [1]. In the United States (US),

FAQs

What was the study designed to examine?

The study examined whether overall, healthful, and unhealthful plant-based diet indices are associated with the prevalence and severity of depression.

How were diet and depression measured?

Diet was assessed using 24-hour dietary recalls, and depression was measured using the Patient Health Questionnaire-9 (PHQ-9).

What were the main findings regarding hPDI and uPDI?

Higher hPDI scores were associated with lower odds of depression and lower PHQ-9 scores, while higher uPDI scores were positively associated with both depression prevalence and PHQ-9 scores.

Sep 28, 2026

Uploaded by RuangKosong