Changes in serum cholesterol and sterol metabolites after intake of products enriched with an oat bran concentrate within a controlled diet

Background: The serum (S) cholesterol-lowering capacity of oat fibre has been confirmed in several earlier studies. Food products containing oat bran concentrate (OBC) may become a useful tool in the dietary treatment of hypercholesterolaemia when incorporated in the daily diet, but possible adverse effects of processing have to be investigated. Objective: To investigate the S-cholesterol-lowering effect of food products containing OBC in hypercholesterolaemic subjects. Furthermore, to study the effects of the OBC on serum markers of cholesterol (lathosterol) and bile acid (7α-hydroxy-4-cholesten-3-one) synthesis. Design: The study was a single-blind, randomized crossover study, for 2 × 3 weeks. Sixteen hypercholesterolaemic subjects aged 57±7.9 years (mean±SD), with mean S-cholesterol 7.47±0.65 mmol l -1 , were randomized to eat a premade diet containing 5 g oat β-glucan daily (OBC diet) or a control diet (CTRL diet) without β-glucan. Mean β-glucan solubility in the OBC food products was 50%. Results: Serum cholesterol and low-density lipoprotein decreased by 6.0% (p=0.021) and 9.0% (p=0.03), respectively, in the OBC compared with the CTRL diet period. There was no significant differences in lathosterol or 7α-hydroxy-4-cholesten-3-one responses between the diet periods, but the short-term (day 0-3; r=0.64, p < 0.01) and long-term changes (day 0-22; r=0.55, p < 0.05) correlated well with each other. Conclusions: 5 g of β-glucan daily (2.7 g soluble) induced a significant reduction in S-cholesterol when incorporated into food products as OBC. An immediate response in the sterol metabolism was shown shortly after the introduction of the OBC diet. Oat β-glucan-enriched products could be a useful tool in the prevention and treatment of hypercholesterolaemia.