Health Effects of Foods Enriched with Cereal beta-Glucans from Cereals

Sammanfattning: Since soluble fibre in the form of the cereal beta-glucans found in oats and barley has been shown to have a positive effect on lipid and glucose metabolism, people at risk of developing cardiovascular diseases or diabetes might benefit from that a variety of palatable food products containing beta-glucans being available to them. The aim of the papers presented in the thesis was to evaluate the metabolic effects on persons with hypercholesterolemia or type 2 diabetes of various new food prototypes supplemented by beta-glucans. The immunomodulating effects of oat beta-glucan in vitro were also investigated. In paper I, the total cholesterol (T-C) concentration after a daily intake of 3.5 g of beta-glucans contained in a fermented, ropy oat-based product was found to be significantly lower than in a control group. In the same study an oat-based product containing 3.0 g of beta-glucans did not significantly lower the serum lipid level. In paper II a beverage containing 5 g of beta-glucans from oats also significantly lowered the T-C concentration and the postprandial glucose and insulin response as compared with a control beverage. No significant serum lipid or postprandial changes as compared with control were obtained after the consumption of either 5 or 10 g of barley beta-glucans or 10 g oat beta-glucans. In paper III a soup enriched with 4 g of oat beta-glucans was found to lower T-C and LDL-C in healthy hyperlipidemic subjects, although the reductions did not differ significantly from those in a group consuming a control soup. In paper IV, the same beta-glucan-enriched soup was investigated in normocholesterolemic subjects with type 2 diabetes. The tricylglycerol concentration of was significantly reduced in the beta-glucan group but produced no significant improvement in HbA1c or LDL-C. The liquid products used in the studies were all enriched with low Mw beta-glucans, increasing the amounts that could be incorporated per serving. The major difference between the various studies was in the method of administering the products: several servings per day in papers I and II but only once a day in papers III and IV. It could be of further interest to study the optimal mode of consuming beta-glucans and whether barley beta-glucans per se are less effective than oat beta-glucans.