Review 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 Fatemeh Shirani Ph.D. Cand. a, b , Amin Salehi-Abargouei Ph.D. Cand. a, b , Leila Azadbakht Ph.D. a, b, * a Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran b Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran article info Article history: Received 20 September 2012 Accepted 16 December 2012 Keywords: DASH diet Fasting blood glucose Insulin HOMA-IR Randomized controlled trials abstract 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 gly- cemic 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 ¼ 9), fasting insulin (n ¼ 7) and HOMA-IR (n ¼ 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 ¼ 0.1), and HOMA-IR (mean difference 0.26; 95% CI, 0.56 to 0.05; P ¼ 0.1). Conclusions: The DASH dietary pattern may lead to an improvement in insulin sensitivity inde- pendent 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. Ó 2013 Elsevier Inc. All rights reserved. Introduction Type 2 diabetes is a major, worldwide public health problem [1,2]. Genetic, environmental, and behavioral risk factors such as dietary intake and physical inactivity could play a role in the prevalence of this disease [3]. Based on the prediction from the World Health Organization, the prevalence of diabetes for all age groups will be 4.4% by 2030 and the number of people with diabetes is predicted to rise from 171 million in 2000 to 366 million in 2030 [4]. According to the reports, 26% of the U.S. population suffers from impaired fasting glucose (IFG) and 15.8% has impaired glucose tolerance (IGT) [5]. Diet is one of the key lifestyle factors involved in the genesis, prevention, and control of diabetes. Dietary factors are important and are potentially modifiable risk factors. According to the meta-analysis of Carter and co-workers, high intake of green leafy vegetables is significantly associated with a reduced inci- dence of type 2 diabetes [6]. The Dietary Approaches to Stop Hypertension (DASH) diet, which encourages the high intake of whole grain, fruits, vegetables, and low-fat dairy products combined with sodium restriction, was originally developed to prevent hypertension. However, it is now recommended as an ideal eating dietary pattern for all adults [7,8]. The DASH diet is high in fiber, antioxidant components, unsaturated fatty acids, and low-fat dairy, which may improve insulin resistance [8,9] and hyper- glycemia and lower the risk for type 2 diabetes [10]. The DASH eating pattern may play an important role in managing the * Corresponding author: Tel.: þ98 311 792-2719; fax: þ98 311 6682509. E-mail address: azadbakht@hlth.mui.ac.ir (L. Azadbakht). 0899-9007/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.nut.2012.12.021 Contents lists available at ScienceDirect Nutrition journal homepage: www.nutritionjrnl.com Please cite this article in press as: Shirani F, et al., Effects of Dietary Approaches to Stop Hypertension (DASH) diet on some risk for..., Nutrition (2013), http://dx.doi.org/10.1016/j.nut.2012.12.021 Nutrition xxx (2013) 1–9