The food-pharma interface: consequences of combined use of functional foods and statins

It is increasingly being recognised that most chronic diseases are multifactorial in origin. The focus of this thesis was cardiovascular disease (CVD), a multifactorial disease in which a combination of genetic and environmental factors contributes to the aetiology and progression of the disease. To control multifactorial diseases, a treatment approach in which medicines and nutrition complement each other may prove to be the most successful. In the domain of nutrition, apart from (disease-related) dietetic regimes, an increasing number of functional foods and dietary supplements, each with their own health claim, are marketed. These food items are considered to be positioned between traditional foods and medicines at the so-called ‘Food-Pharma interface’. The attention of the European Union regarding functional foods and dietary supplements has been principally directed to food safety and (claims of) efficacy, and most of the research focuses on these two areas. Currently little is known about physiological or behavioural interactions between functional foods or dietary supplements and pharmaceuticals. This thesis aims to start filling the gaps in knowledge in this field and adds to our understanding of the beneficial and harmful effects of the combined use of functional foods/dietary supplements and medicines. The present thesis shows that the use of functional foods and dietary supplements may offer opportunities to reduce health risk factors when combined with prescription drugs. We have shown that functional foods enriched with phytosterols/-stanols lower total and LDL cholesterol by 4% and 5%, respectively, when used in combination with statins in a real-life setting. At the moment, however, it is not clear whether these reductions in cholesterol levels lead to a reduced CVD risk. For functional foods enriched with n-3 polyunsaturated fatty acids (n-3 PUFA) it was found that patients on statin therapy were at a relatively low risk of future cardiovascular events, such that supplementation with n-3 PUFA did not provide additional protection against cardiovascular events. There are also potential problems related to the use of functional foods and dietary supplements. First, their use may increase the risk for physiological food-drug interactions due to the elevated amounts of specific functional ingredients in the diet. In an experimental animal study, it was shown that the cholesterol-lowering effect of statins was reduced when oat beta-glucans were present in the diet of female LDL-receptor deficient mice. Second, we showed that the use of functional foods or dietary supplements may lead people to indulge in self-medication, resulting in lower adherence to drug therapy. Research towards this behavioural interaction is currently lacking and will become more important in the future as the world market for functional foods and dietary supplements is growing.