Pigmented Rice Bran and Plant Sterol Combination Reduces Serum Lipids in Overweight and Obese Adults

Abstract

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/m², 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.

Key words:

• bioactive compounds
• clinical trials
• diets
• general nutrition
• obesity
• preventative nutrition and chronic disease
• supplements and functional foods