SYSTEMATIC REVIEW article
Front. Nutr.
Sec. Clinical Nutrition
Volume 12 - 2025 | doi: 10.3389/fnut.2025.1645789
Nonlinear Dose–Response Relationship Between Dietary Inflammatory Index and Risk of Depression: A Systematic Review and Meta-Analysis
Provisionally accepted
- 1Shandong Second Medical University, Weifang, China
- 2Affiliated Hospital of Shandong Second Medical University, Weifang, China
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Background: Depression is a prevalent mental health disorders that impose a significant global health burden. Emerging evidence suggests that diet plays a critical role in mental health, primarily through its impact on inflammation. The Dietary Inflammatory Index (DII) is a validated tool designed to assess the inflammatory potential of an individual's diet. Objective: To systematically evaluate the association between DII and the risk of depression. Methods: A comprehensive search was conducted in PubMed, Cochrane Library, Embase, and Web of Science from inception to August 9, 2025. Two independent reviewers screened the studies, extracted data, and assessed methodological quality. A meta-analysis was performed to evaluate the association between DII and depression (the main outcome). The dose-response relationship between DII and depression was further analyzed using generalized least squares estimation and restricted cubic spline models in Stata 18.0. Results: A total of 43 studies were included. The meta-analysis revealed that higher DII scores were associated with an increased risk of depression (OR = 1.53; 95% CI: 1.42 to 1.66; I² = 81.5%). Subgroup analyses stratified by study design, gender, age, region, dietary assessment methods, depression assessment tools, and body mass index (BMI) consistently showed a positive association between higher DII and depression risk. Dose-response analysis indicated a nonlinear relationship (p = 0.0019): no significant association was observed for DII scores below 0, whereas the risk increased progressively for scores above 0. Exploratory analyses of a smaller subset of studies suggested a similar trend for anxiety, but this finding should be interpreted with caution. Conclusion: Higher DII scores are associated with an increased risk of depression. These results highlight the potential benefits of reducing pro-inflammatory dietary components and encouraging anti-inflammatory eating patterns to support mental health, particularly in the prevention of depression.
Keywords: Dietary inflammatory index, Diet, Depression, Dose-response relationship, Systematic review, Meta-analysis
Received: 12 Jun 2025; Accepted: 28 Aug 2025.
Copyright: © 2025 Yu, Bian, Ren, Wei, Zhang and Miao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lirong Yu, Shandong Second Medical University, Weifang, China
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