Adherence to Dietary Approaches to Stop Hypertension (DASH)-Style Diet and the Risk of Cancer: A Systematic Review and Meta-Analysis of Cohort Studies

Objective: Several investigators have proposed a protective association between dietary approaches to stop hypertension (DASH) style diet and risk of cancers; however, they have had 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, Scopus, and Google Scholar were searched for cohort studies published up to July 2018. Relative risks (RRs) that 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 nine reports assessed the association between the DASH diet and risk of mortality from all cancer types, four assessed incidence of colorectal cancer, and two studies assessed the risk of colon and rectal cancer separately. Four studies examined the association with the incidence of other cancers (breast, hepatic, endometrial, and lung cancer). Meta-analysis showed that high adherence to DASH is associated with a decreased mortality from all cancer types (RR = 0.84, 95% confidence interval [95%CI]: 0.81-0.86). Participants with the highest adherence 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) cancers compared to those with the lowest adherence. Conclusion: DASH-style diet should be suggested as a healthy approach associated with decreased risk of cancer in the community. Prospective studies exploring the association for other cancer types and from regions other than the United States are highly recommended.