Statins are a group of cholesterol-lowering medications that prevent cholesterol production in the body by inhibiting the enzyme, HMG-CoA reductase. Not all statins are affected by grapefruit consumption. The Harvard Medical School Family Health Guide says that the statins that are significantly boosted by grapefruit consumption include, atorvastatin, lovastatin and simvastatin, but fluvastatin, pravastatin and rosuvastatin are not.
Enzyme Inhibition
Grapefruit contains the flavanone, naringin and the two furanocoumarins, bergamottin and dihydroxybergamottin. These compounds inhibit enzymes in the intestine and liver that transport and breakdown certain drugs, including some statins. When the breakdown of these drugs is inhibited, their concentrations increase in the body. An article in the American Journal of Cardiovascular Drugs says that the components in one glass of grapefruit juice or whole fresh fruit segments will inhibit enzymes that metabolize certain statins and increase their serum concentrations even if the drugs are taken 24 hours later. There is some controversy over how much one normal glass of grapefruit juice raises the serum concentrations of statins, and some people are much more vulnerable to its effects than others.
Adverse Health Effects
The most common adverse side effects of statins are gastrointestinal upset, muscle cramps and pain, and peripheral neuropathy, which causes tingling, numbness and pain in the extremities. A serious condition of acute muscle breakdown, also known as rhabdomyolysis, has been rarely reported.
Recommendations
A review in the August 2006 issue of the American Family Physician says that people taking certain statins should exclude grapefruit from their diet or choose an alternate medication that does not interact with grapefruit. The study says that grapefruit is low in calories and high in vitamin C, potassium and fiber and has been a recommended fruit of the American Heart Association's "Healthy Heart Campaign." But a letter in the July 2007 issue of the American Family Physician says that people should not be persuaded from consuming grapefruit because it is healthy and that it would be better to inform patients taking these drugs to consume a glass of grapefruit juice in the morning and take their statin drugs in the evening.
References
- Harvard Medical School Family Health Guide: Grapefruit and Medication: A Cautionary Note
- American Journal of Cardiovascular Drugs: Interactions Between Grapefruit Juice and Cardiovascular Drugs
- American Family Physician: Management of Grapefruit-Drug Interactions
- American Family Physician: The Grapefruit-Drug Interaction Debate: Role of Statins
