DIETARY TOTAL ANTIOXIDANT CAPACITY AND RISK OF GASTROINTESTINAL CANCERS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF OBSERVATIONAL STUDIES

Background and Aim: Gastrointestinal (GI) cancers are common types of cancers. Among different factors that affect etiology of GI cancers, diet has an important contribution. Dietary antioxidants decrease oxidative stress which plays a pivotal role in carcinogenesis. Several studies assessed the relation between dietary total antioxidant capacity (TAC) and risk of GI cancers. Dietary TAC was measured by three indices including FRAP, TRAP, and TEAC. We performed a systematic review and meta-analysis of published studies to determine the association between dietary TAC and GI cancers risk.Methods: Eligible studies were selected from PubMed, ISI Web of Science and Scopus databases till May 2018. Case control and cohort studies that reported GI cancers risk estimates for dietary TAC were included. We applied random-effects to estimate pooled relative risks. Subgroup analysis were done based on study design. Results: Among seven observational studies that were included, four were cohort studies and three were case-control studies. Dietary FRAP, TRAP, and TEAC reduced GI cancers risk, (0.71; 95%CI: 0.58-0.85), (0.65; 95%CI: 0.57-0.75), (0.70; 95%CI: 0.59-0.83), respectively. Conclusion: This study indicated that dietary TAC significantly decreased the risk of GI cancers. Nevertheless, further prospective studies are required to clarify the association between dietary TAC and risk of GI cancers.

کلیدواژه ها:

Dietary total antioxidant capacity ، gastrointestinal cancers ، cancer risk ، FRAP ، TRAP ، TEAC