Say It Ain't So, Oleo!

It was one of the simplest pieces of advice a doctor could give: to reduce the risk of heart disease, hold the butter and spread margarine instead. And over the past two decades, millions of people have made the switch, believing they were replacing cholesterol-raising saturated fats with cholesterol- lowering unsaturated fats.

The issue may not be that simple. A study by two Dutch scientists reported in last week's New England Journal of Medicine found that one of the ingredients in stick margarine actually increases the risk of heart disease. At fault are the so-called trans monounsaturated fatty acids used as hardeners in margarines, shortenings and commercial frying fats. The new research indicates that this kind of fatty acid, like the saturated fats found in butter, can raise the level of LDL, the type of cholesterol known to clog arteries.

No, it is not time to switch back to butter, says Dr. Scott Grundy, a University of Texas expert on cholesterol who wrote the journal's accompanying editorial. Butter, cheese and whole milk are still more damaging to blood cholesterol levels than any margarine, and all should be eaten in moderation. The real message, says Grundy, is that manufacturers have to find a better way to make their butter substitutes. Perhaps the easiest solution would be to replace the trans fatty acids with stearic acid, which is also a solid at room temperature but has not been shown to raise cholesterol levels in the blood.

The problem with stearic acid is that it is technically a saturated fat. And it would have to be classified as such on margarine labels that give a breakdown of the different kinds of fats in the product. That would confuse people conditioned to think that saturated fats are uniformly bad and unsaturated fats always good. Grundy believes it may be time to rethink the way labels are worded. His suggestion: identify which ingredients are cholesterol-raising. That may be the only way for consumers to know if a particular margarine contains the fats that are easiest on the heart.