Statins, Sterols, and Stanols

Abstract & Commentary

By Russell H. Greenfield, MD, Editor

Synopsis: Margarines containing plant sterols and stanols can be an effective long-term therapeutic intervention to aid with cholesterol lowering in people already on a stable statin regimen.

Source: de Jong A, et al. Effects of long-term plant sterol or stanol ester consumption on lipid and lipoprotein metabolism in subjects on statin treatment. Br J Nutr 2008;100:937-941.

Combining treatments for recalcitrant dyslipidemia that have differing mechanisms of action could be of greater benefit to patients than simply doubling the dose of standard agents. The authors of this small randomized, double-blind trial examined the effects of long-term plant sterol or stanol consumption on cholesterol levels and apolipoproteins in patients already on a stable statin regimen.

A total of 54 people (32 men) completed this trial (data evaluable on n = 47) where participants were asked to replace their usual spread with a "light" margarine. After a brief run-in period, subjects were randomized to one of three groups for a total of 85 weeks: control margarine; a plant sterol-enriched margarine (2.5 g/d); and a plant stanol-enriched margarine (2.5 g/d). Subjects were asked to weigh the margarine tubs daily to ensure 30 g daily consumption, and to return the tubs for weighing at weeks 5, 50, and 90. During these same times participants completed a Food Frequency Questionnaire regarding the previous four weeks' food intake, and energy intake was calculated by participating dietitians. Fasting blood samples for various lipid parameters were obtained at weeks 0, 4, 5, 9, 10, 29, 30, 49, 50, 69, 70, 89, and 90.

Results showed that subjects in both the sterol and stanol groups experienced a significant additional decrease in total and LDL cholesterol. At weeks 45 and 85, total cholesterol declined in the plant sterol group by 0.49 (8.8%) and 0.29 (5.1%), respectively. Total cholesterol declines in the plant stanol group for the same time periods were 0.82 (6.9%) and 0.50 (9.4%). With respect to LDL-C measures at 45 and 85 weeks, levels decreased by 0.40 (11.6%) and 0.28 (8.7%) in the plant sterol group, and by 0.31 (8.7%) and 0.42 (13.1%) in the plant stanol group. ApoB decreased only in the plant stanol group. The study authors concluded that both plant sterols and plant stanols effectively lower cholesterol levels when regularly consumed by people already on a stable statin regimen.

Commentary

Previous studies of the effectiveness of sterols and stanols for management of high cholesterol have reported promising results, but most were short-term trials. In this 85-week trial subjects tolerated therapy with their supplemented margarines well, and experienced significant improvements in their lipid profiles while on statins.

Both sterols and stanols have a chemical structure similar to cholesterol, and it is believed that they act by limiting intestinal absorption of cholesterol. Both are most commonly found as components of functional foods, especially margarines marketed to those with high cholesterol.

de Jong's group put together a very nice trial notable for its duration and the frequency of lipid level measurement. On the flip side, the sample size is small, and while subjects were asked not to change their dietary and exercise patterns during the trial there was no objective verification of this. Research suggests that simply being enrolled in a study can promote lifestyle and dietary changes, some of which may have impacted study results.

The good news is that this paper adds to a sizable amount of data supporting the use of plant sterols and stanols as adjunctive therapy for the treatment of high cholesterol. Keep in mind that it behooves patients to read labels when buying their margarines, however, as many still contain trans fats.