a very early age. It was recently shown that polymorphisms in the ABCG5 and ABCG8 genes contribute to modifying serum plant sterol levels in healthy, non-sitosterolaemic individuals. Furthermore, several epidemiological studies have shown that the risk of developing heart disease seems to be increased even at more "normal" plant sterol levels. Since statins were shown to increase serum plant sterol concentrations, patients should probably not be treated with statins alone but with a combination therapy focusing simultaneously on improving the serum lipoprotein profile and lowering serum plant sterol concentrations. Cholesterol absorption The molecular mode of actions of stanols has been described in several preclinical and clinical trials and can be divided into two steps: Step 1: Cholesterol absorption occurs via the formation of micelles with bile acids. Stanols displace cholesterol from these micelles so that less cholesterol is absorbed. Stanols need to be taken as part of a meal in order to be incorporated in the micelles. Step 2: In vitro studies have shown that stanols activate LXR alpha, LXR beta and ABCA1 transporter proteins. It is thus hypothesised that stanols work in enterocytes by activating the excretion of cholesterol back into the intestinal lumen. Only stanols have been proven to retain their efficacy in long-term use, most likely due to the minimal absorption of stanols, and consequently their lack of effect on bile acid metabolism. As a consequence of the reduced absorption of cholesterol, the absorption of fat-soluble components other than cholesterol, such as vitamins and antioxidants, may also be reduced. Like cholesterol, carotenoids and tocopherols are transported by lipoproteins. Since the number of LDL particles in circulation decreases after consumption of plant sterols or stanols, plasma concentrations of carotenoids and tocopherols also decrease. This is why these antioxidants are often standardized to plasma lipid concentrations. The results of randomised, placebo-controlled trials on the effects of plant sterols or stanols on fat-soluble vitamins and antioxidants were summarised in 2003. Significant reductions were only seen in clinical trials for hydrocarbon carotenoids. These reductions are probably caused by reduced absorption and lower plasma concentrations of the carrier, LDL. After correcting for cholesterol levels, only the reduction in the β-carotene level remained. It is important, however, that carotenoid and tocopherol levels remained within the normal ranges. Clinical trials also showed that when following the recommended diet, including consumption of vegetables and fruit, carotenoid levels did not decrease. Plasma concentrations of retinol (vitamin