When it comes to lowering LDL cholesterol by diet, margarine does it better than butter. That's one of the results in a study from the University of Texas Southwestern Medical Center. Researchers there compared the cholesterol-lowering effects of 2 diets - one using butter, the other margarine - on 46 families. All followed special individualized diets low in saturated fat. When margarine was used, LDL levels dropped 11% in adults and 9% in children.

The other major finding was that the response of individuals to a cholesterol-lowering diet is familial - that is, members of some families had greater success than other families, and no other variables accounted for the differences. Also, heavier individuals had higher LDL levels to start with and lower response to the dietary change.