Plant sterol-ester and stanol-ester margarines reduce elevated low-density lipoprotein (LDL) levels by 10 to 15 percent. This effect occurs through a reduced absorption of dietary and biliary cholesterol. Because a compensatory increase in cholesterol production occurs, the simultaneous use of a statin drug with a stanol-ester margarine may increase the drop in LDL. Simons and associates studied the effects of adding sterol-ester margarine to ongoing statin therapy in the management of hypercholesterolemia.

Men and women with documented primary hypercholesterolemia and baseline LDL cholesterol levels of at least 97 mg per dL (2.50 mmol per L), regardless of previous statin treatment, were randomized to one of four groups after a four-week washout of all lipid-lowering treatment and collection of baseline studies. The four double-blind treatment groups included the following: (1) placebo plus regular margarine; (2) placebo plus sterol-ester margarine; (3) cerivastatin in a dosage of 400 mcg plus regular margarine; and (4) cerivastatin in a dosage of 400 mcg plus sterol-ester margarine. This study was initiated before the withdrawal of cerivastatin from the market, but the results are still valid because the mechanism of action of cerivastatin is similar to that of other statins. All participants were asked to consume 25 g per day of margarine during two meals, representing an intake of 2 g per day of plant sterol. Clinical observations and laboratory testing were performed at each visit in the washout period and the four-week treatment period.

Among the 152 participants included in the analysis, the group treated with cerivastatin and sterol-ester margarine showed a decrease in LDL equivalent to that occurring with sterol-ester margarine alone. This efficacy of cerivastatin and sterol-ester margarine also occurred in total cholesterol and serum apolipoprotein-B levels. There was no significant effect on high-density lipoprotein cholesterol or apolipoprotein-A1 levels. Adverse effects were similar among all four groups, and there were no clinically significant changes in muscle and liver enzymes.

The authors conclude that when a sterolester margarine is added to statin therapy, the increased effect on LDL is similar to that obtained when using the sterolester margarine alone. This demonstrates that the additional effect achieved by adding the plant margarine is simply additive to that of the statin rather than based on an interaction that yields a greater effect. The LDL-lowering effect of sterol- or stanol-ester margarine, used alone or with a statin, is probably between 8 and 15 percent.

editor's note: A daily consumption of 2.5 g of plant stanols appears to successfully lower LDL cholesterol. Plat and associates determined that consumption of this amount of plant stanols once per day at lunch was as effective as dividing this daily consumption over three daily meals. Results of a study by Williams and colleagues demonstrated the efficacy of plant stanol ester consumption in reducing total and LDL cholesterol in healthy preschool-aged children who consumed a total daily dose of 3 g in three daily servings. These studies support the addition of dietary plant stanols to lower serum cholesterol. The optimal amount of daily intake has not yet been determined, although a study by Hallikainen and associates found that daily doses of stanol as low as 1.6 g provide significant cholesterol reduction, with minimal improvement occurring with doses of 2.4 to 3.2 g daily.—R.S.