Red yeast rice appears to lower blood cholesterol and triglyceride levels with few side effects, but there is no evidence that it can treat cancer.
Little is known about the way red yeast rice works. One of its constituents, monacolin K, also known as lovastatin, is an active ingredient in the cholesterol-lowering drug, Mevacor®. The drug works by inhibiting an enzyme essential for the creation of cholesterol in the body. Therefore, it is assumed that red yeast rice works through a similar mechanism.
To lower high cholesterol
A few clinical trials show that the use of red yeast rice can reduce cholesterol and triglyceride levels in the blood.
Citrinin, a toxic fermentation byproduct, has been found in a number of preparations of red yeast rice.
Grapefruit juice may increase the effects of red yeast rice.
Muscular disease resulting in muscle weakness
A 63-year-old woman developed severe hypertransaminasemia following use of Equisterol, an over-the-counter lipid-lowering product containing guggulsterol and red yeast rice extract, for 6 months. Her symptoms normalized after equisterol was discontinued.
A 62-year-old woman developed severe hepatitis following use of red yeast rice capsules for approximately 4 months before admission. Her condition improved after discontinuing red yeast rice.
The U.S. Food and Drug Administration declared that the dietary supplement Cholestin, manufactured by Pharmanex, cannot be marketed as a dietary supplement because it contained lovastatin, a prescription drug.
Used in China as food and medicine for thousands of years, red yeast rice is the fermented product of the fungus, Monascus purpureus, grown on rice. It was first marketed as a dietary supplement in the United States by Pharmanex under the trade name Cholestin (1). The active constituent, monacolin K, is the same as lovastatin, an active ingredient in the cholesterol-lowering drug (2). A number of clinical trials have demonstrated effectiveness of red yeast rice preparations in reducing cholesterol levels in hyperlipidemic patients (3)(4)(5)(14)(15)(16)(17), but one of the extracts tested did not lower blood pressure in hypertensive patients (20). In another study, co-supplementation with Coenzyme Q10 was found to be associated with improved LDL-cholesterolemia and endothelial reactivity in moderately hypercholesterolemic subjects (22).
It is important to note that several preparations of red rice yeast contain citrinin, a toxic fermentation byproduct (6).
Mechanism of Action
Components such as citrinin, monacolines and monankarin, and monascopyridines have been isolated from red yeast rice (10). Fermentation products are standardized to contain 0.4% 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors. HMG-CoA reductase is the rate-limiting enzyme in endogenous cholesterol biosynthesis (1). The principal HMG-CoA reductase inhibitor is monacolin K, also known as lovastatin (11).
Citrinin, a toxic fermentation byproduct, was found at measurable concentrations in a number of preparations (6).
Grapefruit juice may increase the effects of red yeast rice (9).
Stomach ache (3), heartburn, dizziness and flatulence (7), liver injury and myopathy (21)(23).
Anaphylaxis in a 26-year-old man (8) and rhabdomyolysis in a 28-year-old renal transplant recipient (12).
A 63-year-old woman developed severe hypertransaminasemia following use of Equisterol, an over-the-counter lipid-lowering product containing guggulsterol and red yeast rice extract, for 6 months. Symptoms normalized after equisterol was discontinued (18).
A 62-year-old woman developed severe hepatitis following use of red yeast rice capsules for approximately 4 months before admission. Her condition improved after discontinuing red yeast rice (19).
Coenzyme Q10: Red yeast rice contains lovastatin which has been shown to lower coenzyme Q10 levels (13).
Schulz V, Hansel R, Tyler VE. Rational Phytotherapy: A Physician’s Guide to Herbal Medicine. New York: Springer, 2001.
Wang J, et al. Multicenter clinical trial of the serum lipid-lowering effects of a Monascus purpureus (red yeast) rice preparation from traditional Chinese medicine. Current Therapeutic Research, Clinical & Experimental 1997 58(12):964-978.