The connection between cholesterol-lowing statins and grapefruit relates to how the body can metabolize these medications. Specifically, grapefruit juice can reduce the metabolism rate of statins, thus causing too much of the cholesterol medications to collect in the body. In most cases, this happens only if a quart (0.95 liters) or more of grapefruit juice is consumed. Some people might experience adverse effects with only one daily glass of grapefruit juice or one whole grapefruit.
Statins are prescribed to people who have high cholesterol levels. It works by decreasing the liver’s ability to produce low-density lipoprotein (LDL), or “bad” cholesterol, and slightly increasing the production of high-density lipoprotein (HDL), or “good” cholesterol. Statins immediately lower cholesterol levels. After about six weeks of treatment, long-term effects are present.
Normally, CYP3A4, an enzyme in the liver, destroys a significant portion of the statins before they can be absorbed into the bloodstream. Not only does this enzyme reduce the amount of statins absorbed, but it also causes them to be absorbed more slowly. Grapefruits contain furanocoumarins, which can inhibit the enzyme’s function. As a result, too much medication will be metabolized too quickly.
People who want to continue drinking grapefruit juice should consider purchasing juice that has had the furanocoumarins removed during production, which can help avoid the problems involved when statins and grapefruit are consumed. Solvents and absorption resins can be used to remove 99 percent of furanocoumarins. All other natural ingredients of the grapefruit juice are retained. Therefore, the taste and other health benefits are not changed.
If too many statins remain in the bloodstream, serious side effects can occur. Serious muscle conditions, such as myopathy or rhabdomyolysis, can result from the toxicity. In turn, kidney failure, liver failure or other life-threatening disorders can be triggered. Combining statins and grapefruit can even cause death.
Not all statins are affected. Grapefruit juice is not known to cause drug interactions with some high-cholesterol medications because they use a different enzyme than other medications. Grapefruit has no effect on the enzyme used by these medications. Other drugs are known to interact.
Regardless of the cholesterol medication taken, experts suggest that precaution be taken. It is best to avoid all grapefruit juice, whole grapefruit or grapefruit supplements if taking a drug that utilizes the enzyme CYP3A4. Other statins and grapefruit should not be consumed within a few hours of each other. If serious side effects occur, one should seek immediate medical attention to lessen the risk of long-term health problems.