Research highlights red yeast rice reactions over 14 years

Red yeast rice (RYR) is often used by patients with high cholesterol, and is hailed as an alternative to statin drugs. It has an EU-approved health claim​​ for cholesterol management at 10 milligrams (mg) per day of its prime constituent, monacolin K.

However researchers have collated some adverse effects over more than a decade, including myopathies and liver issues.

Adverse reaction tally​

Scientists from Sapienza University and the National Institute of Health in Rome in Italy analysed 1261 suspected adverse reactions (ARs) recorded in World Health Organisation (WHO) databases.

From April 2002 to September 2015 there were 52 RYR ARs. 

These reactions ranged from muscle pain and/or increase in creatine phosphokinase (19), muscle injury (1), liver injury (10), gastrointestinal reactions (12), skin reactions (9) and other reactions (4).

Women were involved in 70% of cases and 13 cases resulted in hospitalisation. 28 of these patients were taking other medications including ACE inhibitors,  thyroid  hormones,  selective  serotonin  re-uptake  inhibitors,  oral  contraceptives, antibiotics,  benzodiazepines,  calcium  antagonists, beta-blocking  agents  and diuretics. Some were taking food supplements such as vitamin  D, fish  oil and olive extracts.

“Monacolin K contained in RYR is identical to lovastatin,  and  early  monitoring  of  liver  function  and  signs  of  muscle  injury should be considered,”​ the study’s authors recommended.  

“When used as self-prescription, without medical advice and monitoring and possibly for long term, patients should be aware adverse reactions, such as hepatitis or rhabdomyolysis, can remain asymptomatic for long periods.”​

RYR is derived by fermenting steamed rice with a fungus belonging to the Monascus genus, mainly M. purpureus ​(Aspergillaceae  family).

During this process monacolins are produced as well as pigments, which are responsible for the rice’s red colour.

Between 2009 and 2013, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) recorded 30 ARs linked with food supplements containing RYR, mainly consisting of myopathies and liver injury. It is not known if these were also logged with the WHO.

The researchers recommended future studies using questionnaires to gain information on specific uses of RYRs in order to make cross-national comparisons.

Source: British Journal of Clinical Pharmacology​

Published online ahead of print: DOI: 10.1111/bcp.13171​​

“Adverse reactions to dietary supplements containing red yeast rice: assessment of cases from the Italian surveillance system.”​

Authors: G. Mazzanti et al.