Both red yeast rice, made by fermenting yeast on top of red rice, and grapefruit pectin, made from the pulp and peel of the fruit, can have cholesterol-lowering effects. Red yeast rice contains monacolin K, also known as lovastatin, the same drug found in prescription statins used to lower cholesterol levels. Grapefruit can change the absorption of many medications, including statins. If you're taking red yeast rice containing lovastatin, you should not also take grapefruit pectin to lower cholesterol.
Red Yeast Rice Actions
The active ingredient in red yeast rice that lowers cholesterol, called lovastatin or mevinolin, has the same actions as the prescription version of the drug. Statin drugs block the action of an enzyme called HMG-CoA reductase, which helps the body produce cholesterol. But prescription drugs contain a precise amount of drug, where the drug amount in red yeast rice can vary. For this reason, the U.S. Food and Drug Administration does not allow red yeast rice sold in the United States to contain lovastatin.
Grapefruit Actions
Grapefruit pectin may also help lower cholesterol, according to two studies published in the September 1988 issue of "Clinical Cardiology" by researchers from the University of Florida. The first, an animal study, found that miniature swine fed grapefruit pectin in their diet had significantly lower cholesterol, 168 mg/dl compared to 249 mg/d. The second, a human study, found that grapefruit pectin lowered cholesterol by 7.6 percent and low-density lipoprotein, the "bad" cholesterol, by 10.8 percent over a 16-week period in people with medium to high risk of coronary artery disease.
Grapefruit's Effect on Lovastatin
While both grapefruit pectin and red yeast rice may have benefit in lowering cholesterol, using them at the same time could cause harm. Grapefruit can change the way you metabolize lovastatin in a way that causes more of the drug to be absorbed. This can result in dangerously high levels of the drug entering your bloodstream.
Concerns
Since the amount of lovastatin in red yeast rice is not controlled, the amount present could exceed the normal therapeutic dose. Adding grapefruit pectin could increase the amount of lovastatin you ingest to even higher levels. At high doses, statins can cause a serious muscle breakdown called rhabdomyolysis, which allows toxins to enter the bloodstream that can damage the kidneys. Kidney failure and death can occur in severe cases. Statins can also cause liver damage in some people.
References
- Drugs.com: Red Yeast Rice
- "Clinical Cardiology"; Grapefruit Pectin Inhibits Hypercholesterolemia and Atherosclerosis in Miniature Swine; P. Baeky, et al.; September 1988
- MayoClinic.com; Red Yeast Rice; July 2011
- "Clinical Cardiology"; The Effects of Grapefruit Pectin on Patients at Risk for Coronary Heart Disease Without Altering Diet or Lifestyle; J. Cerda, et al.; September 1988
- Medline Plus; Red Yeast Rice; May 2011
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