Physicochemical properties of oat β-glucan influence its ability to reduce serum LDL cholesterol in humans: a randomized clinical trial

Abstract

Background: Consumption of 3 g oat b-glucan/d is considered sufficient to lower serum LDL cholesterol, but some studies have shown no effect. LDL cholesterol lowering by oat b-glucan may depend on viscosity, which is controlled by the molecular weight (MW) and amount of oat b-glucan solubilized in the intestine (C). Objectives: Our 2 primary objectives were to determine whether consumption of 3 g high-MW oat b-glucan/d would reduce LDL cholesterol and whether LDL cholesterol lowering was related to the log(MW · C) of oat b-glucan. Design: In a double-blind, parallel-design, multicenter clinical trial, subjects with LDL cholesterol 3.0 and 5.0 mmol/L (n = 786 screened, n = 400 ineligible, n = 19 refused, n = 367 enrolled, and n = 345 completed) were randomly assigned to receive cereal containing wheat fiber (n = 87) or 3 g high-MW (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 b-glucan/d (divided doses, twice daily) for 4 wk. Results: LDL cholesterol was significantly less with 3 g high-MW, 4 g medium-MW, and 3 g medium-MW oat b-glucan cereals than with the wheat-fiber cereal by 0.21 (5.5%; 95% CI: 20.11, 20.30; P = 0.002), 0.26 (6.5%; 95% CI: 20.14, 20.37; P = 0.0007), and 0.19 (4.7%; 95% CI: 20.08, 20.30; P = 0.01) mmol/L, respectively. However, the effect of 4 g low-MW oat b-glucan/d (0.10 mmol/L) was not significant (2.3%; 95% CI: 0.02, 20.20). By analysis of covariance, log(MW · C) was a significant determinant of LDL cholesterol (P = 0.003). Treatment effects were not significantly influenced by age, sex, study center, or baseline LDL cholesterol. Conclusions: The physicochemical properties of oat b-glucan should be considered when assessing the cholesterol-lowering ability of oat-containing products; an extruded breakfast cereal containing 3 g oat b-glucan/d with a high-MW (2,210,000 g/mol) or a medium-MW (530,000 g/mol) lowered LDL cholesterol similarly by '0.2 mmol/L (5%), but efficacy was reduced by 50% when MW was reduced to 210,000 g/mol. This trial was registered at www.clinicaltrials.gov as NCT00981981.Am J Clin Nutr 2010;92:723-32.

Emulsion gels as potential fat replacers delivering β-glucan and healthy lipid content for food applications

“…3)-linked cellotetraosyl units (Wood et al 1994). b-glucans extracted from cereals such as barley or oats play a significant role in reduce cardiovascular diseases or the symptoms of diabetes (Tapola et al 2005;Wolever et al 2010).…”

“…Oat bran contains high-quality proteins, vitamins and unsaturated fatty acids; however, the chief nutritional attribute of oat bran is that it provides soluble dietary fibre, primarily b-glucan (Arendt and Zannini 2013) which is associated with several health benefits (Wolever et al 2010). A health claim has been associated with this component: oat beta-glucan can actively lower/reduce blood LDL and total cholesterol (EFSA 2010).…”

Dietary Fiber Future Directions: Integrating New Definitions and Findings to Inform Nutrition Research and Communication

“…A critical analysis of epidemiological studies including strategies should include ways to deal with multiple confoundings and interactions. One possible way to address this is with study designs such as those of Pal et al (32) that looked at potential synergy of fibers in food with fibers added to food. One confounding issue that needs to be addressed includes a separation of the effects of fiber, especially cereal fiber, from whole grains.…”

Exploiting natural variation to improve the content and composition of dietary fibre in wheat grain: A review

“…In fact, the strongest evidence for health benefits of food is for wholegrain cereals, and particularly for the DF fraction. Benefits associated with increased consumption of cereal DF include lowering blood pressure and serum cholesterol, improving insulin sensitivity, and reducing the incidence of bowel and breast cancers (RiChArdSon, 2000;CAde et al, 2007;ToPPing, 2007;ButtriSS & StokeS, 2008;AnderSon et al, 2009;Tighe et al, 2010;WoLever et al, 2010;Aune et al, 2011; EFSA PAneL on dietetiC ProduCtS, nutrition And ALLergy, 2011). Soluble forms of DF may also be especially beneficial, conferring viscosity, which contributes to reduced serum cholesterol and slowing the digestion and absorption of food, reducing the glycaemic load (ToPPing, 2007;Tighe et al, 2010).…”