Postlaunch monitoring of functional foods can encompass monitoring of effectiveness under conditions of customary use. To this end, the effectiveness of phytosterol/-stanol enriched margarine consumption in free-living conditions was investigated with data from the Dutch "Doetinchem cohort study". In total, 4505 subjects (aged 26-70 years) were examined in 1994-1998 and re-examined during 1999-2003. A general and a food frequency questionnaire and non-fasting blood samples for total and HDL cholesterol determination were obtained. Subjects were stratified into phytosterol/-stanol enriched margarine users (n = 84) and non-users (n = 4421) based on the re-examination data, as these margarines were available on the Dutch market from 1999 onwards.Mean spontaneous daily use (g ± SD) of phytosterol-containing margarine (n = 71) was 15 ± 8 and of phytostanol-containing margarine (n = 13) 9 ± 6. After five years, total blood cholesterol had increased with 0.26 mmol/l in non-users while it had not significantly changed in users. The difference in total blood cholesterol change in users versus non-users was −0.30 mmol/l (p < 0.001). The beneficial effect of the phytosterol/-stanol enriched margarine, used under customary conditions can be characterized as a stabilization of cholesterol levels. This is the first report finding a modest beneficial effect on blood cholesterol level under customary conditions thereby partly confirming findings from clinical trials.

The consumption of products enriched with plant sterol or stanol esters lowers serum total and LDL-cholesterol concentrations, thereby most likely reducing the risk of coronary heart disease. However, using plant sterol (not plant stanol) enriched products elevates serum plant sterol concentrations in humans. This may be unwanted because health effects of elevated serum plant sterol concentrations are still controversial. Within postlaunch monitoring of functional foods, we compared serum plant sterol and plant stanol concentrations among users of plant sterol (n = 67) or plant stanol (n = 13) enriched margarines with those of matched nonusers (n = 81) in the ongoing Dutch Doetinchem cohort study. Subjects (aged 29-67 y) were examined in 1994-1998 (before the introduction of enriched margarines) and re-examined in 1999-2003. Serum concentrations of plant sterols and stanols were measured in samples from nonfasting subjects by GLC-MS. Intake of plant sterols was 1.1 +/- 0.6 g/d and was associated with a decrease of serum total cholesterol concentration of 0.25 +/- 0.91 mmol/L (4%, P < 0.05), a change that differed (P < 0.05) from the nonsignificant increase in nonusers (+2%, 0.12 +/- 0.78 mmol/L, P = 0.16). Cholesterol-standardized serum sitosterol and campesterol increased in plant sterol users by 22% (P < 0.0001) and 103% (P < 0.0001), respectively. Cholesterol-standardized serum sitostanol and campestanol increased in plant stanol users by 197% (P = 0.02) and 196% (P = 0.01). To our knowledge, these data are the first to show changes in serum cholesterol, plant sterol, and plant stanol concentrations after (long-term) consumption of plant sterol and stanol enriched margarines in a free-living population in a nonexperimental setting. Whether the increased serum sterol concentrations result in adverse side effects needs to be investigated in future postlaunch monitoring studies.

Background: Studies on effectiveness of phytosterol/-stanol-enriched margarines in the community have received low priority. For postlaunch monitoring purposes including risk-benefit analyses, it is needed to investigate both exposure and effectiveness of these margarines. Objective: To study the use and effectiveness of phytosterol/-stanol-enriched margarine. Design, setting and subjects: The study population consisted of 2379 subjects that participated in a community intervention study ('Hartslag Limburg') aged 28-76 years. In 1998 and 2003, blood samples for total and high-density lipoprotein (HDL) cholesterol were obtained. A general questionnaire and food frequency questionnaire (FFQ) were administered. From 1999 onwards, phytosterol/-stanol-enriched margarines were introduced on the Dutch market. On the basis of 2003 data, subjects were classified in users of (a) phytosterol/-stanol-enriched margarine, (b) cholesterol-lowering drugs, (c) the combination (both enriched margarine and drugs) and (d) neither enriched margarines nor cholesterol-lowering drugs. Results: Mean (7s.d.) daily intake of phytosterol-enriched margarine (n ¼ 99) and phytostanol-enriched margarine (n ¼ 16) was 1479 g. From 1998 to 2003, total serum cholesterol concentration changed significantly different among the four groups: in the combination users À2.0471.50 mmol/l (À29%), in cholesterol-lowering drug users À1.0971.17 mmol/l (À17%), in the enriched margarine users À0.2470.75 mmol/l (À4%) and in non-users þ 0.1070.72 mmol/l ( þ 2%)(Po0.05). Conclusion: Recommended doses are not consumed, but phytosterol/-stanol-enriched margarines can modestly reduce serum total cholesterol in the community. These margarines cannot equal the effect of cholesterol-lowering drugs, but may act additively. Further investigation of the health effects that may occur during simultaneous cholesterol lowering drugs and phytosterol-or -stanol-enriched margarines usage is important, as well as community education about the cholesterol lowering foods and drugs.

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