S’pore team finds that untreated rice extract can hinder liver function
RED yeast rice (hong qu mi), used widely in traditional Chinese medicine (TCM) and food, has often been praised for helping to lower cholesterol, as it contains compounds called monacolins. A low dose of red yeast rice extract has roughly the same effect on cholesterol levels as a higher dose of lovastatin, a cholesterol-lowering drug.
But a team of researchers from Nanyang Polytechnic (NYP) and TCM firm Eu Yan Sang has discovered that this bright reddish fermented rice can also interfere with Western drugs. Their research was published earlier this month in the journal Nature Scientific Reports, a newer, smaller offshoot of the prestigious Nature journal.
Under Eu Yan Sang’s three-year-old collaboration with NYP, researchers had previously noticed that red yeast rice contains a portion of water-soluble compounds, which they called Fraction X, whereas the cholesterol- lowering monacolins are not water-soluble. Dr Henry Leung, a lecturer at the polytechnic and the lead researcher, said the team then found that untreated red yeast rice extract interfered with liver cells’ ability to break down drugs after they are absorbed by the body, while extract treated to remove Fraction X did not. And it found that untreated extract caused a spike in drug levels in the blood of rats, whereas treated extract did not.
One of the next steps is to find out what exactly is in Fraction X that allows it to affect drug metabolism. Another is to test its effect on humans, said Dr Joel Lee, director of life sciences at NYP’s school of chemical and life sciences. But could ordinary consumers accidentally overdose on Western drugs by consuming red yeast rice – commonly used as a food colouring in dishes such as char siu and red rice wine mee sua – since it interferes with the drugs being cleared from the body? Dr Leung said the possibility existed. “The effect can vary from individual to individual, so it’s hard to gauge the amount at which red yeast rice would have that effect.”
Singapore College of Traditional Chinese Medicine vice-principal Clement Ng, who was not involved in the research, explained that in general, TCM practitioners advise clients to time their consumption of Western medications and TCM preparations at least two hours apart. “It’s a case-by-case basis... It depends on the constitution of the patient, and whether the patient is taking any conflicting medication. For instance, if the patient is taking bloodthinning medication, we don’t prescribe something similar,” he said.
The work was funded by Spring Singapore’s Innovation Development Scheme. The research has led to a patented way to extract Fraction X from red yeast rice to leave just the monacolins, and Eu Yan Sang Singapore managing director Vincent Lim said the firm will launch a commercial red yeast rice product this year