Drug Induced Liver Injury (DILI) due to variability in monacolin K content in Red Yeast Rice (RYR): An expert opinion

Introduction: Red yeast rice (RYR) is an effective cholesterol-lowering nutraceutical reversibly inhibiting 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase. As liver damage is a possible (albeit rare) side effect of HMG-CoA inhibitors, it make sense to focus on the tolerability of the liver to RYR extracts. The aim of this paper is to offer an expert opinion on the risk of liver damage by the use of RYR extract. Methods: A review of the available literature has been carried out and critically reviewed by the authors. Results: According to a large meta-analysis of 53 randomized clinical trials comprising 112 treatment arms, which included 8535 subjects with 4437 in the RYR arm and 4303 in the control arm of the study, RYR administration was not associated with increased risk of Drug Induced Liver Injury (DILI) during RYR treatment. Single cases of DILI have been associated with the use of RYR supplements. Even if the causal relationship is hardly demonstrable, it is possible that products containing impurities or toxic elements such as citrinin or unstandardized dosages of bioactive compounds like monacolins, could be implicated in liver toxicity. Conclusion: DILI associated with RYR intake are exceptional and hardly associated to RYR per se rather than to low-quality products. Nutrivigilance and stricter manufacturing regulations should be implemented and are recommended in order to protect consumers from low quality and potentially dangerous dietary supplements.