Introduction

The butter vs. margarine debate slows many consumers on their trip down the grocery aisle, as they stop to scan the food labels for nutrition information. Margarine manufacturers advertise that their product is made from "heart healthy" vegetable oil, but butter producers point out that some margarine also contains trans fats, which, like saturated fat, can have an unhealthy effect on blood cholesterol. The American Heart Association, however, has ruled in favor of margarine, a view supported by the results of a study recently reported in the Journal of the American Medical Association.

A closer look at margarine and butter

In this latest analysis, 46 families used either margarine or butter in their meals for a five-week period, and then switched to the other spread for another five weeks. They limited their intake of foods high in saturated fat (other than butter), and all the baked goods they consumed were specially prepared with either butter or margarine. Levels of blood cholesterol were measured at the start and end of the study.

As expected, participants' cholesterol levels were lower when they followed the "margarine" diet than when they followed the "butter" diet. This makes sense, because their intake of saturated fat and cholesterol was significantly lower when they limited their intake of foods (like butter) that are high in animal fat.

Who you are affects how you respond

Not everyone responded equally to the dietary changes, however. The researchers noted that people in some families registered greater shifts in blood cholesterol levels than those in other families, suggesting that genetics may influence how much of an effect diet has on cholesterol levels. They also say that body weight may play a part in cholesterol control. Heavier study participants were less likely than leaner individuals to respond to diet changes, meaning that their cholesterol levels stayed higher-than-average even while on the low-saturated fat diet.
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Before consumers reach for margarine, though, they should consider what else the study's authors had to say about margarine and about dietary fat in general.

The method used to convert vegetable oil into margarine (a process called hydrogenation) changes the structure of some of the fat molecules to potentially harmful trans fat. This type of fat mimics saturated fats in that both elevate blood cholesterol levels. In fact, the researchers speculate that the cholesterol-lowering edge that margarine had over butter in this study was somewhat offset by the cholesterol-raising effect of the trans fat in the margarine.

What is the consumer to do?

They advise consumers to choose soft or liquid margarine - both are less hydrogenated, so they have substantially less trans fat than solid stick margarine. An even better choice would be one of the several brands of trans fat-free margarine now on grocery shelves.

But it's important to remember that even a product low in trans fat may have just as many calories as stick margarine or butter, about 100 calories per tablespoon. So consumers should monitor their overall fat intake as well. Soft "diet" margarines are whipped with air and water to increase the volume and decrease the number of calories per serving, but even these products can contribute a significant amount of fat to the diet.

So what's a savvy consumer to do? There are other alternatives to butter and margarine, some of which are just as tasty and even lower in saturated or trans fats. You might try switching to olive oil for a bread spread, or perhaps a low-fat cottage cheese. In some baked goods, some of the margarine and butter can be replaced with applesauce, which has no fat at all.

Butter versus margarine is a personal choice. Some people simply prefer the taste of one over the other. But if you resolve to use less of either whenever you can, you can treat yourself to whichever you prefer for those times when nothing else will do.