Foods must list information on trans fats by 2006.

On July 9, the FDA issued a regulation requiring food manufacturers to list trans fatty acids, or trans fats, on the Nutrition Facts panel of foods. They have until January 1, 2006 to do so. The move is designed to help consumers make healthier food choices, but it could also cause manufacturers to reduce or altogether abandon the use of trans fats in their ingredients. There is a great deal of scientific evidence illustrating the relationship between these fats and an increased risk of coronary heart disease.

Trans fats have been shown to raise levels of LDL ("bad" cholesterol).

As part of a well-known and ongoing prospective study known as the Nurses' Health Study, the Harvard School of Public Health determined specific type of fat intake in 80,082 women ages 34 to 59 with validated questionnaires over a 14-year period. They concluded, "The replacement of 2% of energy from trans fats with energy from unhydrogenated, unsaturated fats would reduce [heart attack] risk by 53%."

Look for trans fats wherever you'd expect to find fat: they may be found in vegetable shortening, margarines, crackers, candies, baked goods, fried foods, many processed foods and salad dressings. Simply stated, saturated fats and trans fats negatively affect cholesterol levels. Polyunsaturated fats and monounsaturated fats (such as olive, canola, flaxseed and corn oils) have good effects. Trans fats are never part of a healthy diet.

The FDA Web site (www.fda.gov/oc/initiatives/transfat/) posts examples of food labels with information on trans fats, which will help you determine where to look for this important data. Until 2006, however, it's necessary to pay attention to listed ingredients to determine trans fat levels in the foods you buy: If the ingredient list includes the words "shortening," "partially hydrogenated vegetable oil" or "hydrogenated vegetable oil," the food contains trans fats. Recall, too, that smaller amounts are present when the ingredient is close to the end of the list. Finally, the more solid a spread is at room temperature, the more trans fats it likely contains; liquid margarine is therefore preferable to stick margarine.

(New Eng. J. Med., 1997, Vol. 337, No. 21, pp. 1491-1499; FDA Web site, www.fda.gov/oc/initiatives/transfat/)