Study calls oat fiber claim into question
expanding the sources of oat beta-glucan soluble fiber that can
carry the health claim for lower risk of heart disease. But adding
the fiber to processed foods seems to have no such heart-healthy
effect.
The Food and Drug Administration (FDA) has finalised its rule expanding the sources of oat beta-glucan soluble fiber that can carry the health claim for lower risk of heart disease.
Food and beverage makers can now add value to products containing oatrim, the soluble fraction of alpha-amylase hydrolyzed oat bran or whole oat flour, by including the heart health claim on packaging.
But questions about the value of oat fiber will certainly be raised by a new study by Dutch researchers, which found that oat beta-glucan may not be as effective at lowering cholesterol when consumed in food as obtained through supplement or beverage form.
The team at Maastricht University found that bread and cookies containing oat beta-glucan higher than the levels specified in the FDA health claim, had no significant effects on cholesterol. But in a second study, orange juice fortified with soluble oat fiber reduced the levels of LDL cholesterol, they reported in this month's American Journal of Clinical Nutrition.
Coronary heart disease continues to be one of the leading causes of death in the US population, but adding oat fiber to foods not normally linked to a heart-healthy diet seems to be ineffective.
The researchers gave 48 subjects (21 men, 27 women) control bread and cookies (rich in wheat fiber) for the first three weeks, and for the next week, subjects randomly received either control products or bread and cookies 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 fiber or beta-glucan from oat bran during the second week of the trial. After a one-week washout period, dietary regimens were crossed over.
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 FDA rule, published as an interim final rule in October 2002 with a comment period, followed a petition by Pepsico's Quaker Oats and chemicals firm Rhodia asking for a fourth source of soluble oat fiber to be added to the 1998 fiber health claim.
The agency said that there was scientific agreement that oatrim with a beta-glucan content of up to 10 per cent on a dry weight basis and not less than that of the starting material may reduce the risk of heart disease.
The regulation is published in the Federal Register, July 28, 2003.
