Dietary inflammatory index and depression: a meta-analysis

Objective: The purpose of the present meta-analysis was to evaluate the association between the inflammatory potential of diet, determined by the dietary inflammatory index (DII (R)) score, and depression. Design: Systematic review and meta-analysis. Setting: A comprehensive literature search was conducted in PubMed, Web of Science and EMBASE databases up to August 2018. All observational studies that examined the association of the DII score with depression/depressive symptoms were included. Subjects: Four prospective cohorts and two cross-sectional studies enrolling a total of 49 584 subjects. Results: Overall, individuals in the highest DII v. the lowest DII category had a 23 % higher risk of depression (risk ratio (RR)=1.23; 95 % CI 1.12, 1.35). When stratified by study design, the pooled RR was 1.25 (95 % CI 1.12, 1.40) for the prospective cohort studies and 1.16 (95 % CI 0.96, 1.41) for the cross-sectional studies. Gender-specific analysis showed that this association was observed in women (RR=1.25; 95 % CI 1.09, 1.42) but was not statistically significant in men (RR=1.15; 95 % CI 0.83, 1.59). Conclusions: The meta-analysis suggests that pro-inflammatory diet estimated by a higher DII score is independently associated with an increased risk of depression, particularly in women. However, more well-designed studies are needed to evaluate whether an anti-inflammatory diet can reduce the risk of depression.