Consumers who struggle to keep their cholesterol in check got some help from their grocery's dairy aisle a couple of years ago with the addition of cholesterol-lowering margarines. These products contain one of two similar, plant-based substances-called stanols and sterols-that inhibit the absorption of dietary cholesterol from the intestine. An Australian study published in the European Journal of Clinical Nutrition adds to what we know of these products' cholesterol-lowering potential.

Diet made a difference

In the first part of this analysis, researchers recruited 22 men and women with elevated blood cholesterol levels. Each consumed meals that included breakfast cereals, bread, and margarine that had been supplemented with either stanols or sterols. After 4 weeks, those on the sterol-supplemented group lowered their LDL ("bad") cholesterol by an average of 13.6%; the stanol-supplemented diet resulted in an 8.3% drop. Even though one regimen appeared to have more of an impact than the other, both represented significant reductions in cholesterol levels.

In the second phase of the study, 15 of the original participants consumed diets that included either a spread high in saturated fat or a sterol-supplemented margarine. As expected, those who consumed the sterol-supplemented margarine lowered their LDL cholesterol an average of 12%, while LDL cholesterol in the other group rose by 6%.

How much is enough?

An interesting point of this study is that, while stanols and sterols are commonly added to margarine, it's possible that they could be added to other foods, giving consumers additional cholesterol-lowering food choices. But, note the authors, more isn't necessarily better, since stanol-and sterol-laced products - which bind with fat in the intestine - may also remove some essential fat-soluble vitamins along with the unwanted cholesterol. Another concern is that scientists don't yet know the long-term effects of high doses of stanols and sterols.

A low-fat diet is the key

Right now, the only commercial food product that they're available in is margarine, and it's important to note that these products alone will not bring elevated cholesterol levels back in line. All fats are high in calories, and for many people, elevated cholesterol and excess weight go hand-in-hand. As part of a low-fat, heart-healthy diet, though, these margarine products may give consumers an added edge in keeping cholesterol levels within normal limits.