Folate Intake and Breast Cancer Risk: A Systematic Review and Meta-Analysis

This study aimed to evaluate the relationship between folate intake and breast cancer risk in adult women. A blinded paired-matched search was conducted in Embase, PubMed/Medline, and Web of Science. Cohort and case-control studies assessing folate intake or supplementation and breast cancer risk were included. The search yielded 377 studies. After exclusion of duplicates and reading of the titles and abstracts, 13 were selected for full-text reading, and 11 met the eligibility criteria. Most studies (n = 8) found a direct association between folate intake and reduced breast cancer risk, with one study observing a U-shaped relationship between dietary folate intake and breast cancer risk. Conversely, three studies found no association with breast cancer risk. Some studies report inconsistencies in the literature. A meta-analysis comparing mean folate intake between case and control groups revealed no statistical significance. Some studies have indicated a possible association between folate consumption and the risk of breast cancer, however the meta-analysis of this study did not confirm this relationship. Results were inconsistent, and the meta-analysis indicated no significant effect.