Effects of Dietary Approaches to Stop Hypertension (DASH) diet on some risk for developing type 2 diabetes: a systematic review and meta-analysis on controlled clinical trials

Objective: Type 2 diabetes is a major public health problem. The Dietary Approaches to Stop Hypertension (DASH) eating pattern may contribute to managing risk factors of type 2 diabetes. The objective of this study was to conduct a systematic review and meta-analysis on randomized controlled trials (RCTs) that examine the effects of DASH diet consumption on the indices of glycemic control such as fasting blood glucose (FBG), serum fasting insulin level, and Homeostatic Model Assessment insulin resistance (HOMA-IR).

Methods: We searched Pubmed, EMBASE, Science direct, ISI web of science, and Google Scholar for RCTs until July 2012. In total we found 20 articles that examine the effect of DASH diet on FBG (n = 9), fasting insulin (n = 7) and HOMA-IR (n = 4) met the inclusion criteria, respectively.

Results: Meta-analysis showed that the DASH diet can significantly reduce fasting insulin concentration (mean difference -0.15; 95% confidence interval [CI], -0.22 to -0.08; P < 0.001). Subgroup analysis based on the study period showed that the DASH diet could significantly reduce fasting insulin levels when prescribed for more than 16 wk (mean difference -0.16; 95% CI, -0.23 to -0.08; P < 0.001). Meta-analysis could not show a beneficial effect of the DASH diet on FBG (mean difference -0.26; 95% CI, -0.56 to 0.05; P = 0.1), and HOMA-IR (mean difference -0.26; 95% CI, -0.56 to 0.05; P = 0.1).

Conclusions: The DASH dietary pattern may lead to an improvement in insulin sensitivity independent of weight loss. The DASH diet may play an important role in glycemic control in long- term interventions. Additional prospective studies regarding the association between DASH diet and risks for type 2 diabetes are necessary.