Molecular Weight Determines Oat Beta-Glucan Efficacy

TORONTOEating an extruded breakfast cereal containing 3 g/d of high-molecular weight (MW)  oat beta-glucan (as OatWell® oat bran from CreaNutrition AG) lowered low-density lipoprotein (LDL) cholesterol by 5 percent, in a University of Toronto study (Am J Clin Nutr 92: 723-732, 2010. doi:10.3945/ajcn.2010.29174). Researchers found the heart-healthy occurred when participates ate cereals that had a high-MW of 2,210,000 g/mol of beta-glucan, such as OatWell, or a medium MW of 530,000 g/mol. However, efficacy was reduced by 50 percent when MW was reduced to 210,000 g/mol. The MW issue may be the reason previous study results on beta-glucans effect on cholesterol have been mixed.

In a double blind, parallel-design, multicenter clinical trial, subjects with LDL cholesterol levels between 3.0 and 5.0 mmol/L (n = 345) were randomly assigned to receive cereal containing wheat fiber (n = 87) or 3 g high-MW OatWell (2,210,000 g/mol, n = 86), 4 g medium-MW (850,000 g/mol, n = 67), 3 g medium-MW (530,000 g/mol, n = 64), or 4 g low-MW (210,000 g/mol, n = 63) oat beta-glucan/d in divided doses, twice daily for four weeks.

LDL cholesterol was significantly less with 3 g high-MW, 4 g medium-MW, and 3 g medium-MW oat beta-glucan cereals than with the wheat-fiber cereal by 0.21 (P =0.002), 0.26 (P =0.0007) and 0.19 (P =0.01) mmol/L, respectively. However, the effect of 4 g low-MW oat beta-glucan/d (0.10 mmol/L) was not significant. Treatment effects were not significantly influenced by age, sex, study center or baseline LDL cholesterol.