Intake of beta-glucan and effect on lipid metabolism in relation to gut microbiota in healthy individuals.
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Background Intake of beta-glucan, a soluble dietary fiber, for minimum 2 weeks may lower serum cholesterol. Soluble dietary fibers are subjected to colonic fermentation, resulting in the production of metabolites that can beneficially affect metabolic regulation in the host, including lipid metabolism. The aim of the current thesis was to investigate effects on lipid metabolism after intake of various amounts of beta-glucan in healthy adults. Methods Fourteen healthy participants were enrolled in this fixed-order crossover study. The intervention was given as three different test meals containing 0.5, 3.5 and 8 g beta-glucan, which were consumed for three consecutive evenings. Serum lipids were measured at baseline and on the following morning after the different interventions. Postprandial triglyceride response was measured at different time points after a glucose load (OGTT). Breath H2 excretion was measured as an indicator of colonic fermentation. Lipoprotein subclasses were quantified from plasma using an NMR metabolomics platform. Data was processed with Microsoft Excel and analyzed with IBM SPSS statistics. Results Intake of 8 g beta-glucan significantly reduced the postprandial triglyceride response after an OGTT compared with baseline. Fasting breath H2 excretion and fasting plasma concentration of acetate and butyrate was significantly increased after intake of all the test meals compared with baseline. In addition, there was a reduction in fasting particle concentration and total cholesterol in the HDL particles after all the test meals. The 0.5g beta-glucan test meal also reduced the triglyceride content in HDL particles. No effect was observed on fasting serum triglyceride and total cholesterol, or on LDL and VLDL subclasses, after intake of any of the test meals. Conclusion Three days of intervention with beta-glucan can reduce postprandial triglyceride response and modulate lipoprotein metabolism in healthy individuals. Whether these effects are due to beta-glucan alone or in combination with other fibers, and if the effects are related to colonic fermentation, is uncertain.
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