DALLAS, June 3 - To reduce the amount of trans fatty acids in the diet, softer margarines should be substituted for harder spreads, according to new statement released by the American Heart Association in today's issue of its journal Circulation.
Trans fatty acids, which can raise blood cholesterol levels, are a byproduct of the conversion of oils or fats to more solid stable forms through a process called hydrogenation. The more solid the form, the more trans fatty acids per ounce. Thus, softer margarines contain lower amounts of trans fatty acids than harder margarines.
The American Heart Association's statement was developed by its Nutrition Committee because trans fatty acids have become such a controversial health issue in the news.
Consumers have been told that margarines, which contain unsaturated fat, when substituted for saturated fat such as butter, can lower cholesterol. However, new studies in the last seven years indicate that some margarines - especially the solid ones -- raise cholesterol almost as much as saturated fats such as butter, says Alice Lichtenstein, D.Sc., author of the statement.
The public didn't know whether to choose margarine or butter, says Lichtenstein, a member of the American Heart Association's Nutrition Committee.
The new guidelines provide a clear message: For cooking, oils in their natural state, such as corn or canola oil, that have not been hydrogenated should substitute for hydrogenated oils or saturated fats. For spreads, softer should replace harder margarines and cooking fats.
"And if you're going to melt it, you might as well start off with a liquid, and then (for spreads) choose softer over firmer," says Lichtenstein.
Trans fatty acids are not listed on the nutrition label of food products, but a person can get a good idea of how much trans fatty acids are included by knowing the total fat content and assessing the appearance (consistency) of the product.
"The best way to reduce trans fatty acids are to lower total fat and choose cooking fats and table spreads that are liquid or soft, and then the individual fats and trans fatty acids will go down too. Trans fatty acids should be viewed in the context of total fat intake," she stresses.
Media advisory: Dr. Lichtenstein can be reached at (617) 556-312799.