The effects of whole grain intake on the metabolic profile in obese girls: a crossover randomized clinical trial

Although whole-grain foods have been reported to affect the metabolic profile, limited data are available in this regard on children. The present study aimed to determine the effects of whole-grain consumption on fasting blood glucose and lipid profile of overweight or obese children. This randomized cross-over clinical trial included 44 overweight or obese (BMI>85th percentile for age and sex) girls aged 8-15 years. After a 2-week run-in period, the subjects were randomly assigned to either an intervention or a control group. The subjects in the intervention group were given a list of whole-grain foods (dark bread (sangak and barbari), brown rice, whole-meal biscuits, wheat germ, wheat bran and cornflakes) and asked to choose and consume 50% of their daily grain servings, for 6 weeks, from among whole-grain foods. Those in the control group were given similarly a list of whole-grain foods and asked not to consume any of those foods during the intervention phase of the study. A 4-week washout period was applied following which the subjects were crossed over to the alternate arm for an additional 6 weeks. Fasting blood samples were taken before and after each phase of study for biochemical measurements and metabolic profile determination. Mean (±SD) age, body mass index, systolic and diastolic blood pressures of the subjects were 11.2±1.49 years and 23.5±2.5 kg/m2, 111.4±9.7 and 66.4±9.1 mmHg, respectively. After 6 weeks we found significant effects of consuming whole-grain foods on plasma glucose (changes from baseline in the intervention group -1.9 vs. 3.8 mg/dL in the control group, P=0.01), serum triglycerides (changes from baseline in the intervention group -16 vs. 7 mg/dL in the control group, P=0.01), and serum HDL-cholesterol levels (changes from baseline in the intervention group 6.3 vs. -5.6 mg/dL in the control group, P=0.05). Whole grain intake had no significant effect on serum total and LDL-cholesterol concentrations or blood pressure. This study provides evidence supporting the beneficial effects of consuming whole-grain foods on the serum levels of fasting blood glucose and lipid profile (TG and HDL) in obese or overweight children.