A randomized controlled trial of dietary fiber intake on serum lipids

Objective: Clinical trials have indicated that water-soluble fiber from oats reduces serum cholesterol among hypercholesterolemic patients on a low-fat diet. We examined the effect of dietary fiber intake on serum lipids among persons without hypercholesterolemia. Design: Randomized controlled trial. Setting and subjects: We recruited 110 participants who were aged 30 - 65 years and had a serum cholesterol level <240 mg/dl from community. Intervention: Study participants were randomly assigned to receive 8 g per day of water-soluble fiber from oat bran or a control intervention. Results: At baseline, the mean levels of serum cholesterol and other measured variables were comparable between the high-fiber and control groups. Over the 3-month intervention, mean changes (95% confidence interval (CI)) in total, HDL-, and LDL-cholesterol were - 2.42 mg/dl ( - 8.90 to 4.05 mg/dl; P = 0.46), - 0.24 mg/dl ( - 2.19 to 1.71 mg/dl; P = 0.81), and - 1.96 mg/dl ( - 7.32 to 3.40 mg/dl; P = 0.47) in the fiber group and - 0.02 mg/dl ( - 5.29 to 5.26 mg/dl; P = 0.99), 1.42 mg/dl ( - 0.74 to 3.59 mg/dl; P = 0.19), and - 0.64 mg/dl ( - 5.30 to 4.03 mg/dl; P = 0.79) in the control group, respectively. The net changes ( 95% confidence interval) in total, HDL-, and LDL-cholesterol were - 2.40 mg/dl ( - 10.6 to 5.81 mg/dl; P = 0.56), - 1.66 mg/dl ( - 4.55 to 1.22 mg/dl; P = 0.26) and - 1.33 mg/dl ( - 8.33 to 5.68 mg/dl; P = 0.71), respectively. Conclusions: Our study does not support the hypothesis that water-soluble fiber intake from oat bran reduces total and LDL-cholesterol in study participants with a normal serum cholesterol level.