EFFECT OF LOW CARBOHYDRATE / LOW FAT DIETARY INTERVENTION ON GENE EXPRESSION OF GLUT IN ABDOMINAL SUBCUTANEOUS ADIPOSE TISSUE OF TYPE 2 DIABETES PATIENTS

Abstract

Type 2 diabetes mellitus (T2DM) global prevalence is increasing rapidly along with obesity marking it as a major public health problem. The causes of its epidemic are embedded in a complex interaction between genes, metabolites and external factors, such as diet. To investigate the short termed effects of a moderate low fat diet (<30% fat, 50% carbohydrate, 20% protein, 1000-1200 kcal/d) and a low-carbohydrate diet (60-70% fat, 5-10% carbohydrate, 20-30% protein, 1200-1500 kcal/d) on metabolic parameters and focusing on diet-induced regulation of glucose transporters (GLUT) in subcutaneous adipose tissue (SCAT) of recently diagnosed T2DM patients. Seventeen T2DM patients were randomly assigned to the low-carbohydrate (LC) diet or to the moderate low-fat (LF) diet. SCAT biopsies and clinical parameters were obtained at baseline and after the 3 weeks dietary intervention. Reverse transcriptase polymerase chain reaction (RT-PCR) was employed to quantify the expression of GLUT in human SCAT. Both interventions led to significant reduction of weight (LC: p=0.004, LF: p<0.000), BMI (LC: p=0.008, LF: p<0.000), LDL/HDL ratio (LC: p=0.004, LF: p=0.002), total cholesterol/HDL ratio (LC: p=0.008, LF: p=0.020) and HbA1c levels (LC: p=0.025, LF: p=0.001). Whereas LDL (p=0.001) and total cholesterol (p=0.003) levels were only significantly reduced after the LF diet, waist-to-hip ratio (WHR) (p=0.013) and triglyceride (TAG) levels (p=0.013) were significantly reduced in the LC group only. After the LF diet, GLUT3 (1.19 ±0.6 to 1.78 ±0.5, p=0.019), mRNA levels increased significantly and, on the contrary, GLUT5 (1.65 ±1.5 to 0.58 ±0.44, p=0.045) mRNA levels showed a significant reduction. No significant differences were observed between diet groups after 3 weeks of diet. This short-term dietary intervention separates the improvements on WHR, TAG, total cholesterol and LDL from dietary composition-related effects. Furthermore, moderate low-fat, calorie-restricted diet may significantly upregulate GLUT3 expression and down-regulate GLUT5 expression in SCAT of T2DM patients. However, future studies on its influence on GLUT transports are needed.