Food makers wishing to promote the health benefits of soluble oat fibre in their products may need to consider the overall effects of the food on heart health.
Oats are recognised by many scientists, and by a US-approved health claim, as helping to reduce the risk of cardiovascular disease but a study by Dutch researchers found that oat beta-glucan consumed in bread biscuits had no effect on lowering LDL cholesterol.
The team at Maastricht University showed in a second study however that orange juice fortified with soluble oat fibre effectively reduced cholesterol levels, they reported in this month's American Journal of Clinical Nutrition.
Food manufacturers are increasingly under pressure to improve the nutritional value of their foods and new regulations in Europe will allow the industry to make health claims recognised across the European community. However desire to boost sales by marketing health aspects may be restricted by the science.
The researchers gave 48 subjects (21 men, 27 women) control bread and biscuits (made with wheat fibre) for the first three weeks, and for the next week, subjects randomly received either control products or bread and biscuits rich in beta-glucan. The average daily intake of beta-glucan was 5.9g. But no differences in LDL cholesterol were observed between the two groups.
In a second study, 25 of the original 48 subjects (10 men, 15 women) were randomly assigned to consume orange juice containing either wheat fibre or beta-glucan from oat bran in a crossover trial.
The beta-glucan drink significantly decreased LDL cholesterol (by 0.26 mmol/L) and also improved the ratio of total to HDL cholesterol compared with the other drink.
"The food matrix or the food processing, or both, could have adverse effects on the hypocholesterolemic properties of oat beta-glucan," warned the researchers in conclusion.
The European Commission recently published a draft proposal on health and nutrition claims, planned to become law in 2005.