Grapefruit is also a useful source of lycopene, which is associated with a reduced risk of cancer. 2. May support heart health. In 2012, the American Heart Association published a report that suggested that a diet high in certain flavonoids, compounds found in citrus fruits including grapefruit, may lower a woman’s risk of stroke. However, more research is needed to understand exactly why. Grapefruit juice decreases the activity of the cytochrome P450 3A4 (CYP3A4) enzymes that are responsible for breaking down many drugs and toxins. Grapefruit contains compounds known as furanocoumarins that block the CYP3A4 enzymes. When grapefruit juice is consumed, the enzyme’s ability to break down the drug for elimination is decreased. Grapefruit peel may never play a prominent role in your diet, but it is edible, and when you trash the peel, you’re also throwing away beneficial nutrients. The peel has significantly more fiber than the pulp. It also contains essential oils, phytochemicals and vitamin C, all of which provide antioxidant protection. Grapefruit juice contains compounds called furanocoumarins that stop CYP3A from doing its job. As a result, more of the drug is absorbed, making it more powerful than it's meant to be — even toxic in some cases. Not all statins are affected equally by grapefruit juice, so grapefruit fans might want to switch to a statin that's less affected (see the table below). But if you can't switch. Grapefruit contains a chemical that can interfere with your body’s ability to break down or metabolize certain statin medications. When statin takers eat large amounts of grapefruit, the level. Grapefruit and grapefruit juice can negatively interact with medications in several different classes. However, not all drugs in each class of medications are affected. Some of the drugs that interact with grapefruit include: Allegra (fexofenadine), an allergy medication.