Mohammad Ali Mohsenpour - Nutrition and Food Security Research Center, Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Roohallah Fallah-Moshkani - Food Security Research Center, Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
Reza Ghiasvand - Food Security Research Center, Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
Hossein Khosravi-Boroujeni - Menzies Health Institute Queensland, and Public Health, School of Medicine, Griffith University, Gold Coast Campus, QLD, Australia

Background and Aim: Several investigations have proposed a protective association between dietary approaches to stop hypertension (DASH) style diet and risk of cancers; however, they have led to inconsistent results. The present study aimed to systematically review the prospective cohort studies and if possible quantify the overall effect using meta-analysis.Methods: PubMed, EMBASE, Scopus, and Google Scholar were searched for cohort studies published up to July 2017. Relative risks (RRs) which were reported for fully adjusted models and their confidence intervals were extracted for meta-analysis. The random effects model was used to combine the RRs.Results: Seventeen studies were eligible to be included in the systematic review from which 9 reports assessed the effects of DASH diet on risk of mortality from all cancer types, four on the incidence of colorectal cancer, and two on the risk of colon and rectal cancer. Four studies examined the association with the incidence of other cancers (breast, hepatic, endometrial, and lung cancer). Meta-analysis showed that high adherence with DASH is associated with the decreased mortality risk of all cancer types together (RR=0.84, 95% confidence interval (95%CI):0.81-0.86). Participants who adhered closest to the DASH diet had a lower risk of developing colorectal (RR=0.79, 95%CI: 0.75-0.83), colon (RR=0.80, 95%CI: 0.74-0.87) and rectal (RR=0.84, 95%CI: 0.74-0.96) cancer compared to those with the lowest adherence.Conclusion: The dash-style diet should be suggested as a healthy approach associated with decreased risk of cancer in the community. Prospective studies exploring the effect on other cancer types and from regions other than the United States are highly recommended.

DASH-style diet; Dietary patterns; Cancer; Systematic review; Meta-analysis