Background: Findings about the effects of beta-glucan on serum lipoproteins are conflicting.
Objective: The study investigated the effects of beta-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 beta-glucan. Mean daily intake of beta-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 beta-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 beta-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 beta-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 beta-glucan.