The Effect of Low Glycemic Index Diet on Blood Pressure and Obesity among Adolescent Girls with Excess Weight

BACKGROUND AND OBJECTIVE: Although several investigators have evaluated the effects of the dietary glycemic index on obesity and hypertension among adults, few and controversial evidence reported for adolescents. Furthermore, no studies examined the effect of low glycemic index diet (LGI) on obesity and hypertension in comparison to healthy nutritional recommendation (HNR) based diet. This study was run to compare the effects of low glycemic index (LGI) diet on blood pressure and anthropometric measurements to HNR based diet in adolescent girls.METHODS: Fifty mature adolescent girls aged less than 18 participated in this parallel randomized clinical trial. Those whose body mass index (BMI) was between 85th and 95th percentile of BMI for age table provided by WHO were determined as overweight and those whose BMI was higher than 95th percentile were determined as obese. Randomized allocation assigned subjects to LGI diet or healthy nutritional recommendation (HNR) based diet. Macronutrient distribution was similar between two groups. A menu of allowable foods and a list of HNRs were delivered to LGI and HNR group respectively. Nutritional status during the study was evaluated by four dietary records. Measuring of blood pressure and anthropometric variables were conducted at baseline and after intervention. (IRCT: 201109272839N4)FINDINGS: Finally, the information of 41 subjects was analyzed. Those in LGI group had GI lower than 50 (42.67±.067). Significant reductions were observed in weigh (71.40±2.23 vs. 68.97±2.03 in LGI group and 77.95±3.48 vs. 75.81±3.39 in HNR group p=0.0001 for both) and BMI (27.97±0.55 vs. 26.71±0.48 in LGI group and 28.82±1.01 vs. 27.75±0.97 in HNR group p=0.0001 for both) in both groups. Changes in blood pressure (diastolic blood pressure: -0.25±4.46 in LGI group vs. -0.21±2.72 in HNR group p=0.995 and systolic blood pressure: -1.19±2.52 in LGI group vs. -2.36±2.43 in HNR group p=0.743) and anthropometric variables (weight: -3.24±0.78 in LGI group vs. -2.70±0.60 in HNR group p=0.582, waist circumference: -4.99±1.18 in LGI group vs. -1.07±2.08 in HNR group p=0.221, BMI: -4.35±0.92 in LGI group vs. -3.65±0.58 in HNR group p=0.514) were not different between two groups.CONCLUSION: The result of this study showed that low glycemic index diet has no effects on obesity and hypertension.