CHAPEL HILL, N.C., May 9 (UPI) -- U.S. researchers have identified the substance in grapefruit juice that causes potentially dangerous interactions with certain medications.
For many years doctors and pharmacists have told patients to avoid grapefruit juice if they are being treated with certain medications, including some drugs that control blood pressure or lower cholesterol.
Studies have shown that grapefruit juice can cause more of these drugs to enter the blood stream, resulting in undesirable and even dangerous side effects.
It was originally assumed that the ingredients responsible for drug interactions were the flavonoids that give grapefruit juice its bitter taste.
However, a study by Dr. Paul Watkins of the University of North Carolina at Chapel Hill shows that a group of chemicals called furanocoumarins are the likely culprit.
"This is the best evidence to date that furanocoumarins are the active ingredients in grapefruit juice that cause the interaction with medications," said Watkins.
The findings appear in the American Journal of Clinical Nutrition.
