About half of the supplements with Red Yeast Rice extract contain such a high quantity of natural statins that you'd expect them to improve cholesterol levels. And about a third of all Red Yeast Rice supplements contain a fungal toxin that can cause kidney damage. Cardiologists at the University of Pennsylvania discovered that not all supplements manufacturers are careful.
Every drugstore stocks supplements containing Red Yeast Rice Extract, which reduce cholesterol levels. The supplements contain monacolins. One of these, monacolin K, is sold in synthetic form as the statin lovastin. Statins inhibit the production of cholesterol in the liver, and reduce the concentration of the 'bad' cholesterol LDL in the blood.
The researchers studied the effects of a Red Yeast Rice supplement on people with raised cholesterol levels who react badly to pharmacological statins. [Ann Intern Med. 2009 Jun 16; 150(12): 830-9, W147-9.] [Am J Cardiol. 2010 Jan 15; 105(2): 198-204.] The experiments had a successful outcome. The several monacolins in Red Yeast Rice apparently have fewer side effects than administering a high dose of a single statin, and they are effective too.
In another study the researchers discovered that a combined approach of Red Yeast Rice supplements, fish-oil capsules and improvements in lifestyle were equally as effective as a regular pharmacological approach for people with too high cholesterol levels. [Mayo Clin Proc. 2008 Jul; 83(7): 758-64.]
Sounds good, but there's one problem. When the researchers bought 12 supplements and analysed them, they discovered that the amount of active ingredient varied considerably. Lovastin or monacolin K [structural formula shown below left] is effective in doses of a few dozen milligrams per day. Cardiologists use doses of up to 80 mg per day. In the table below, which shows the amount (in mgs) of monacolins that users ingest on a daily basis if they keep to the recommended dosage, you can see that about half of the Red Yeast Rice supplements contain sufficient active ingredient.
The researchers also found the fungal toxin citrinin [structural formula below right] in some Red Yeast Rice supplements.
In high concentrations citrinin, which by the way is also found sometimes in cheese and grain products, damages lab animals' kidneys. It is not clear what quantity is required for this to happen in humans. According to the EFSA a daily intake of 0.2 microgram per day per kg bodyweight is safe, but that's an extremely cautious estimate. [EFSA Journal 2012; 10(3): 2605.] Despite these ifs and buts, the researchers are concerned about the more than thirty percent of the Red Yeast Rice supplements in which they found the mycotoxin. In their opinion, consumers would do best to avoid foods containing high concentrations of citrinin.
The researchers do not say what quantities they found in which supplements.
The American ConsumerLab also analysed a dozen Red Yeast Rice products a couple of years ago. These analyses confirmed the findings of the cardiologists at the University of Pennsylvania. [consumerlab.com 5/20/11] [naturalproductsinsider.com July 1, 2008] does name names.
Arch Intern Med. 2010 Oct 25;170(19):1722-7.