Lifestyle modification is an important part of CVD (cardiovascular disease) prevention, particularly in the large proportion of the population with a low ten-year risk, but high lifetime risk. The NCEP (National Cholesterol Education Program) recommends consuming 5-10g of viscous soluble dietary fibre daily to lower LDL cholesterol.
Oats are an important source of soluble fibre, and it is well documented that the main component, beta-glucan, lowers LDL cholesterol. Regulatory agencies in Europe, the US and Canada have approved the use of blood cholesterol lowering claims for food products that provide 3g oat beta-glucan daily.
Systematic reviews and meta-analyses had previously found that oat beta-glucan was only two-thirds as effective at reducing LDL cholesterol when delivered in liquid format rather than solid foods. However, the authors of the present study speculated that this may have been because the oat beta-glucan used had lower molecular weights.
A previous study by the same research team supports this hypothesis. The study found that the ability of oat beta-glucan to lower LDL cholesterol was reduced by 50% when molecular weight was 220,000 g/mol compared with 2,200,000 or 530,000 g/mol.
Does molecular weight play a role?
The PepsiCo-funded study was therefore designed to evaluate the cholesterol lowering effect of consuming a beverage containing 1g of oat beta-glucan with a molecular weight of 2,000,000g/mol three times daily for four weeks.
The randomised, double-blind, placebo-controlled, parallel-arm design clinical trial was conducted by contract research organisation INQUIS Clinical Research. Participants were 191 healthy males and females aged between 18 and 65, with LDL cholesterol of between 3.00 and 5.00 mmol/L. 96 were assigned to the control group (rice milk drink containing no beta-glucan) and 95 to the test group (an oat product containing 1g beta-glucan). After four weeks of drinking the beverages three times daily, LDL cholesterol was measured. A reduction in mean LDL cholesterol of 5% or more was considered clinically significant.