SOFT SELL; TUB MARGARINE, OIL FOUND HEALTHIER THAN HARDER FATS.

Byline: Brigitte Greenberg Associated Press

In a head-to-head comparison of all the things you can smear on a piece of toast or melt in the bottom of a frying pan, doctors have concluded that softer is better.

A study in today's New England Journal of Medicine looked at how harder, processed fats - such as stick margarine, butter and lard - affect cholesterol levels when compared with softer products like tub margarine and oil.

The softer products were found to be healthier because the harder ones have more of what are called trans-fatty acids, which raise cholesterol and the risk of heart disease.

``Does it matter which fat you use? The bottom line is, yes, it matters a lot,'' said Alice H. Lichtenstein, who led the study at the U.S. Department of Agriculture Nutrition Center at Tufts University in Boston.

Lichtenstein said patients with moderately high cholesterol should cut out stick margarine. But she also said people would be better off without butter as well.

``People need to watch both. Because butter is very low in trans-fatty acids does not mean that people should choose butter, because it is so high in saturated fat,'' she said.

Trans-fatty acids are created during a production process called hydrogenation, which transforms vegetable oil into a more solid substance so that it will resist spoiling. Usually, foods list ``partially hydrogenated'' oil on the label.

In the study, 18 women and 18 men over 50 were each fed one of six diets for five weeks. Each diet provided 30 percent of calories from fat. Participants were given either soybean oil, semiliquid margarine, soft margarine, shortening, stick margarine or butter. Participants eventually were fed all six diets, and the researchers measured the effects on their cholesterol levels after each five-week period.

Researchers checked the participants' levels of two opposing cholesterol forces in the bloodstream: LDL, or bad, cholesterol, which can clog arteries, and HDL, or good, cholesterol, which protects against heart disease.

People who consumed soybean oil reduced their levels of LDL cholesterol by an average of 12 percent compared with those who ate butter. Those given semiliquid margarine lowered their levels 11 percent.

Among those who ate soft margarine, the level dropped 9 percent, and for shortening, the level fell 7 percent. Those who ate stick margarine reduced their LDL cholesterol only 5 percent.

Conversely, those who ate the softer fats had smaller reductions in HDL cholesterol.

In another journal article, Walter C. Willett of the Harvard School of Public Health and colleagues noted that in Europe, manufacturers have been quicker to produce margarines free of trans-fatty acids and low in saturated fat, while stick margarines still occupy a large portion of grocery store shelves in the United States.

Willett and Dr. Ronald M. Krauss of the American Heart Association said the Food and Drug Administration should require that trans-fatty acids be labeled on products.

Willett also said the FDA should require fast-food restaurants to label menu items because fried fast foods and commercially baked goods often contain trans-fatty acids.

``Trans-fat is the largest amount of artificial chemical in our food supply,'' Willett said. ``I think a lot of parents are concerned about their kids' health, and they should have the information that their kids are eating a type of fat that can be extremely dangerous.''

The National Association of Margarine Manufacturers criticized the research, saying the full-fat stick margarine used in the study is not representative of the products now found in most supermarkets.

Manufacturers have come up with products significantly lower in total fat, saturated fat and trans-fatty acids, the association noted.

NAMM President Richard Cristol said the industry would not oppose mandatory labeling of trans-fatty acids.

``We would welcome the opportunity to use the package label to show consumers how we are meeting their demands for healthy, good-tasting and convenient margarine products,'' he said.