ReviewEffects 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
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 incidence 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 hyperglycemia and lower the risk for type 2 diabetes [10]. The DASH eating pattern may play an important role in managing the risk factors of patients with type 2 diabetes [8]. However, the effect of the DASH diet on the risk for type 2 diabetes is still unclear. According to our knowledge there is no meta-analysis on the effects of the DASH diet on the indices of glycemic control. To summarize the available literature, we conducted a meta-analysis of studies on randomized clinical trials (RCTs) that examined the effects of DASH diet consumption on some of the risk factors for developing type 2 diabetes, such as fasting blood glucose (FBG), serum fasting insulin levels, and Homeostatic Model Assessment insulin resistance (HOMA-IR).
Section snippets
Search strategy
We searched Pubmed, EMBASE, Science direct, ISI web of science, and Google Scholar for studies until July 2012, using following keywords: DASH or Dietary Approaches to Stop Hypertension combined with glucose, fasting blood glucose, FBS, Insulin, and HOMA-IR. Our search retrieved about 762 studies. All titles and if needed abstracts were reviewed by authors to find RCTs eligible to include in the study. Cohort study, cross-sectional, case–control, and review articles were excluded. Our
Results
Nine RCTs [9], [11], [12], [13], [16], [17], [19], [20], [21] were used for systematic review and meta-analysis. Their characteristics and main outcomes are shown in Table 1. Two of the studies[11], [21] examined the effect of the DASH diet on FBG, insulin, or HOMA-IR by using a randomized crossover design, one study used a randomized crossover design without wash out [19], one a non-randomized crossover design [20] and five studies reported their results not using cross-over design [9], [12],
Discussion
In the present meta-analysis of RCTs, we found that the DASH diet can significantly reduce fasting insulin concentration compared with a control diet. Subgroup analysis based on study period showed a significant effect of adherence to the DASH diet on fasting insulin concentration on longer period of time (>16 wk). It should be noted that with the elimination of the study by Lien et al. [16], a significant relationship between the DASH diet and a reduction in fasting insulin concentration
Conclusions
The results of the present meta-analysis suggest that the DASH diet can improve insulin sensitivity. The DASH dietary pattern may play a role in glycemic control in long-term interventions. Further prospective studies about the association between the DASH diet and risk factors for type 2 diabetes are necessary.
References (36)
- et al.
The Dietary Approaches to Stop Hypertension Eating Plan Affects C - reactive protein, Coagulation Abnormalities, and HepaticFunction Tests among Type 2 Diabetic Patients
J Nutr
(2011) - et al.
Soy inclusion in the diet improves features of the metabolic syndrome: a randomized crossover study in postmenopausal women
Am J Clin Nutr
(2007) - et al.
Meta-analysis in clinical trials
Control Clin Trials
(1986) - et al.
Whole-grain intake and the risk of type 2 diabetes: a prospective study in men
Am J Clin Nutr
(2002) - et al.
Daily magnesium supplements improve glucose handling in elderly subjects
Am J Clin Nutr
(1992) - et al.
Changes in plasma, erythrocyte, and platelet magnesium levels in normotensive and hypertensive obese subjects during oral glucose tolerance test
Am J Hypertens
(1999) - et al.
Hypocaloric high-protein diet improves glucose oxidation and spares lean body mass: comparison to hypocaloric high-carbohydrate diet
Metabolism
(1994) - et al.
Normotensive women with type 2 diabetes and microalbuminuria are at high risk for macrovascular disease
Diabetes Care
(2006) - et al.
Projection of diabetes burden through 2050
Diabetes Care
(2001) - et al.
Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance
N Engl J Med
(2001)