Meta-analysis of the effect of β-glucan intake on blood cholesterol and glucose levels

Objective: A meta-analysis was performed on epidemiologic studies to assess the relation between beta-glucan consumption from oats and from barley on blood cholesterol level, triglyceride/triacylglycerol (TGL/TAG) level, and blood glucose level (BGL) in humans. In addition, the effect of beta-glucan on total cholesterol (TC) and BGL was translated into an empirical dose-response model. Methods: Thirty research articles that evaluated the effect of different exposure levels of beta-glucan on blood cholesterol and BGL were analyzed, yielding 126 clinical studies. Results: There was a significant inverse relation in TC (-0.60 mmol/L, 95% confidence interval [Cl] -0.85 to -0.34), low-density lipoprotein (-0.66 mmol/L, 95% Cl -0.96 to -0.36), and TGL/TAG (-0.04 mmol/L, 95% Cl -0.15 to 0.07) after consumption of beta-glucan. In contrast, an increase in high-density lipoprotein cholesterol was noted (0.03 mmol/L, 95% Cl -0.06 to 0.13) with the random-effect model. The analysis showed a significant change in BGL (-2.58 mmol/L, 95% Cl -3.22 to -1.84) with high heterogeneity between (I-2 = 97%) and across (tau(2) = 5.88) the studies. The fixed-effect model showed a significant change in TC, low-density lipoprotein, and BGL, whereas it showed no significant changes in high-density lipoprotein and TGL/TAG. The dose-response model showed that a 3-g/d dose of oat or barley beta-glucan was sufficient to decrease TC. Conclusion: Consumption of 3 g/d of oat or barley beta-glucan is sufficient to decrease blood cholesterol, whereas the effect on BGL is still inconclusive, with high heterogeneity, and requires further clinical research studies with longer intervention periods. (C) 2011 Elsevier Inc. All rights reserved.