Food supplements with red yeast rice: More regulations are needed

Dietary supplements are widely used in Europe and abroad. By definition, they should provide nutrients that may otherwise not be consumed in sufficient quantities. However, there are numerous food supplements marketed as self-medication substances promoting health related issues. Among these there are products containing red yeast rice (RYR) promoting the maintenance of normal blood low-density lipoprotein (LDL) cholesterol concentrations. This property is due to the content of monacolins, among which monacolin K, which is chemically identical to lovastatin, is the most important. In randomized placebo-controlled trials it has been shown that RYR reduces triglycerides and totaland LDL-cholesterol. Like statins monacolin K is an inhibitor of the HMG-CoA reductase enzyme that is involved in the synthesis of cholesterol. A dose of RYR containing about 5–7mg of monacolin K is considered as effective in lowering cholesterol as 20–40mg of pure lovastatin. In this issue of the European Journal of Preventive Cardiology Pieter A Cohen and co-workers report on the variability in strength of RYR supplements purchased from mainstream retailers. They analysed 28 brands of RYR supplements for monacolin K content. Monacolin K was not detected in two brands; in the other 26 the quantity of monacolin K ranged more than 60-fold. Following the intake recommended by the manufacturers the quantity of monacolin K consumed per day would range more than 120-fold, from 0.09 to 10.94mg. In other studies the quantity of monacolin K in RYR supplements also varied a lot. In a report of the Superior Health Council of Belgium the quantity of monacolin K in supplements notified to the health authorities by the manufacturers varied 30-fold. This variation is dependent on the strain of yeast selected and of specific features of the fermentation process. This large variation in monacolins content of RYR supplements may introduce large differences in the lipid lowering effects within and between individuals. There may also be a large inter-individual variation in the response to a given dose of monacolin K, comparable to what has been observed for a given dose of a given statin. These large variations in the quantity of monacolin K in RYR supplements and a possible inter-individual variation in the response to a given dose of RYR raise questions as to the effectiveness and the safety of these supplements. Adverse effects of statins have been well documented and are dose dependent. The combination of RYR supplements with statins could make the risk for side effects even greater; these supplements are freely available and do not contain any warning as to possible adverse reactions. RYR is also an inhibitor of isoforms of cytochrome P450 (1A2 and 2C19) and of the glycoprotein P (P-gp), meaning that interactions with other drugs exist, which may lead to an increased risk of adverse effects. Over the past years several reports have appeared concerning side effects of RYR supplements. In Europe surveillance systems of dietary supplements exist in only a few countries. In France a national system of ‘nutrivigilance’ exists; over a period of four years 30 reports were received related to RYR supplements. The adverse effects that were reported relate to muscle symptoms, liver enzyme abnormalities, allergic, skin and gastro-intestinal reactions. Within the Italian surveillance system of natural health products 55 suspected adverse reactions due to the intake of dietary supplements containing RYR were collected from 2002 to 2015; in 14 cases (27%) the reactions were serious. The authors concluded that the safety profile of RYR supplements seems to be similar to that of statins. Similar adverse effects have also been reported in other scientific journals. Uncertainties related to safety issues also exist when it comes to the composition of these products; some may also contain monacolins other than monacolin