Cholesterol-lowering effect of β-glucan from oat bran in mildly hypercholesterolemic subjects may decrease when β-glucan is incorporated into bread and cookies

Abstract

Background: Findings about the effects of β-glucan on serum lipoproteins are conflicting. Objective: The study investigated the effects of β-glucan from oat bran in bread and cookies (study 1) and in orange juice (study 2) on serum lipoproteins in mildly hypercholesterolemic subjects. Design: In study 1, 48 subjects (21 men, 27 women) received for 3 wk control bread and cookies rich in wheat fiber. For the next 4 wk, by random assignment, 23 subjects continued to consume the control products, and 25 received bread and cookies rich in β-glucan. Mean daily intake of β-glucan was 5.9 g. Total dietary fiber intake did not differ significantly between the groups. In study 2, the same sources of control fiber and β-glucan (5 g/d) as in study 1 were provided. For 2 wk, 25 of the original 48 subjects (10 men, 15 women) were randomly assigned to consume orange juice containing either wheat fiber (n = 13) or β-glucan from oat bran (n = 12). After a washout period of 1 wk, dietary regimens were crossed over. Results: In study 1, the change in LDL cholesterol did not differ significantly (−0.12 mmol/L; P = 0.173) between the 2 groups. In study 2, the drink rich in β-glucan decreased LDL cholesterol by 0.26 ± 0.07 mmol/L (6.7 ± 1.8%; P = 0.001) and the ratio of total to HDL cholesterol by 0.26 ± 0.11 (5.4 ± 2.1%; P = 0.029) compared with the other drink. HDL-cholesterol and triacylglycerol concentrations did not change significantly. Conclusions: The food matrix or the food processing, or both, could have adverse effects on the hypocholesterolemic properties of oat β-glucan.