Ultra-processed food intake and risk of depression: a systematic review

Objective: to conduct a systematic review of the observational studies analyzing the association between ultra-processed food (UPF) intake and the risk of depression. Design: the search adhered to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA); a search for observational studies published until June 2020 was performed in PubMed, Embase, Cochrane Library, and Web of Science databases, followed by additional manual searches. Eight reviewers, working independently in teams of two, screened studies for eligibility, extracted data, and assessed risk of bias. We resolved disagreements through discussion or, if necessary, through adjudication by a third (LH). And the study assessed cross-sectional studies using the Agency for Healthcare Research and Quality (AHRQ) methodological checklist and cohort and case-control studies using the Newcastle-Ottawa Scale (NOS) for quality. We used a tabular format to summarize the articles. Results: twenty-eight studies evaluating UPF intake and risk of depression were finally selected, 21 of which had a cross-sectional design, 6 studies had a cohort design, and 1 had a case-control design. Of these, 4 cohort studies and 17 cross-sectional studies found that consumption of UPF were positively associated with depression or depressive symptoms. Conclusions: our review demonstrated that most studies included in the systematic review showed that UPF consumption is associated with the risk of depression. Future studies should consider the use of validated food intake assessments and standardized depression assessment methods to promote comparability between studies.