Effect of Dietary Approaches to Stop Hypertension Diet versus Usual Dietary Advice on Insulin Receptor Substrate-1Gene Expression: A Randomized Controlled Clinical Trial

Abstract

Background: Insulin receptor substrate (IRS) Type 1 is a main substrate for the insulin receptor, controls insulin signaling in skeletal muscle, adipose tissue, and the vascular, so it is an important candidate gene for insulin resistance (IR). We aimed to compare the  effects of the Dietary Approaches to Stop Hypertension (DASH) and Usual Dietary Advices (UDA) on IRS1 gene expression in women at risk for cardiovascular disease. Materials and Methods: A randomized controlled clinical trial was performed in 44 women at risk for cardiovascular disease. Participants were randomly assigned to a UDA diet or the DASH diet. The DASH diet was rich in fruits, vegetables, whole grains, and low-fat dairy products and low in saturated fat, total fat, cholesterol, refined grains, and sweets,with a total of 2400 mg/day sodium. The UDA diet was a regular diet with healthy dietary advice. Gene expression was assessed by the real-time polymerase chain reaction at the first of study and after 12 weeks. Independent sample t-test and paired-samples t-test were used to compare means of all variables within and between two groups respectively. Results: IRS1 gene expression was increased in DASH group compared with UDA diet (P = 0.00). Weight and waist circumference decreased in DASH group significantly compared to the UDA group (P < 0.05) but the results between the two groups showed no significant difference. Conclusion: DASH diet increased IRS1 gene expression and probably has beneficial effects on IR risks.

Key words: Diet, Dietary Approaches to Stop Hypertension diet, insulin receptor substrate 1gene expression, insulin resistance