OBJECTIVE - This study investigated the dietary effect of including pigmented rice bran with or without plant sterols on lipid profiles during energy restriction-induced weight loss in overweight and obese adults not taking cholesterol-lowering medication. In addition, the study examined the effect of intervention on biomarkers of oxidative stress and inflammation.
METHODS - A group of 24 overweight and obese adults (age: 43 ± 6 years, body mass index 32 ± 1 kg/m(2), 18 females) were randomized to a 25% calorie-restricted diet containing either pigmented rice bran (RB) or the RB with addition of plant sterols (RB+PS) snack bars for 8 weeks. The individualized nutrient-balanced diet contained ∼70% of daily energy needs assessed from indirect calorimetry measured resting energy expenditure (EE) and physical activity-related EE assessed using accelerometry. Anthropometrics, blood pressure, blood lipids, glucose, urinary F2-isoprostanes, C-reactive protein, insulin, and leptin were measured at baseline and after 8 weeks of intervention.
RESULTS - Participants lost approximately 4.7 ± 2.2 kg (p < 0.001). Weight loss was not significant between the RB+PS and RB group (p = 0.056). Changes in body fat corresponded to changes in body weight. Average decrease in total cholesterol was significantly higher in the RB+PS group than in the RB group (difference 36 ± 25 g/dL vs 7 ± 16 g/dL; p = 0.044). A similar pattern was observed for the decrease in low-density lipoprotein (LDL) cholesterol (difference 22.3 ± 25.2 g/dL vs 4.4 ± 18.9 g/dL; p = 0.062). Changes in systolic blood pressure, serum levels of leptin, and F2-isoprostanes were significant between baseline values and after 8 weeks on the diet in both groups (p < 0.05) but did not differ between the 2 groups.
CONCLUSIONS - A nutrient-balanced and energy-restricted diet supplemented with rice bran and plant sterols resulted in a significant decrease in total and LDL cholesterol in overweight and obese adults.