Blood cholesterol

Eating oat beta-glucan regularly helps maintain normal blood cholesterol

Because of the increasing prevalence of cardiovascular disease (CVD), identifying functional foods that reduce CVD risk factors (including high blood cholesterol) is an essential part of research. A body of evidence has accumulated, strengthening the association between oat beta-glucan consumption and a reduction in blood cholesterol, in accordance with an assessment by researchers from the University of Manitoba, Canada.

The researchers reviewed studies that assessed the results of oat beta-glucan on blood cholesterol levels over no less than two weeks. Sourced elements of oat beta-glucan included oat bran, oat meal and rolled oats, that have been consumed as breakfast cereals, biscuits, bread, muesli, muffins, and powders. The selected studies were published between 1997 and 2010; 22 studies met the inclusion criteria (20 clinical trials, 1 systematic review, and 1 meta-analysis).

Beta-glucan, a kind of dietary fibre present in abundance in oats, has been recognised as having blood cholesterol-lowering properties. A major proposed mechanism is that dietary oat beta-glucan forms a viscous layer in the small intestine. The viscous layer attenuates the intestinal uptake of dietary cholesterol along with the re-absorption of bile acids (which the human body makes from cholesterol). In response, the human body draws upon the pool of circulating cholesterol to make new bile acids. Lower uptake of cholesterol from the gut combined with more bodily cholesterol employed for bile acid production results in reduced degrees of cholesterol circulating in the blood.

Overall, the majority of observational studies published since 1997 support a connection between dietary beta–glucan and a reduction in blood cholesterol levels. Daily doses of at the least 3 grams may reduce plasma total and LDL cholesterol levels by 5-10%, respectively. Such intakes can be performed by consuming 2-4 portions daily of oat-based products (e.g. breakfast cereals, breads and crackers).

Interestingly, the mode of administration and/or the foodstuff matrix along with the method of processing the oat products may all influence its cholesterol-lowering abilities. When beta-glucan is put into a liquid matrix, such as for example milk or fruit juice, it seems to be more efficient in comparison to a solid matrix, such as for example bread or cookies which yielded conflicting results. Furthermore, the molecular weight and viscosity of oat beta-glucan may play a significant role in determining its cholesterol lowering ability. It's been observed that the physical structure of beta-glucan is vulnerable to being damaged through the processing and cooking of oats, which might decrease its molecular weight and viscosity. However, this remains a place requiring further research.

The Dietetic Products, Nutrition and Allergies panel of the European Food Safety Authority (EFSA) concluded that on the basis of the data available, a cause and effect relationship has been established between the consumption of beta-glucans and the reduced amount of blood cholesterol concentrations. Hence, these health claim has been approved by EFSA: “Regular consumption of beta-glucans plays a role in maintenance of normal blood cholesterol concentrations.” To be eligible because of this claim, foods should provide at the least 3 grams daily of beta-glucans.

Consistent with the EFSA opinion, the authors concluded that consuming at the least 3 grams daily of oat beta–glucan, within a diet lower in saturated fat and a wholesome lifestyle may promote cardiovascular health.

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