Healthy Habits: Grapefruit

I recently had the opportunity to interview Dr. Donnica L. Moore, MD, about grapefruit and its health benefits, as well as possible drug interactions.

What specific health benefits can grapefruit provide?  

Grapefruit is a “superfood”.  A “superfood” refers to foods that are naturally packed with antioxidants, fiber, vitamins, and minerals. When eaten as a part of a healthy diet, “superfruits” like citrus fruits (such as oranges, lemons and grapefruits) may help reduce the risk of chronic diseases, strengthen the immune system, help control appetite, aid with weight loss and promote skin health.   Studies show that a person can actually lose weight while eating larger quantities of food by choosing foods high in fiber and water content such as citrus fruits. Why does this work? Because these foods contain fewer calories per gram, provide a greater feeling of fullness and help keep blood sugar levels more constant, thereby resulting in increased appetite control. 

 

Citrus fruits are packed with beneficial antioxidants and essential nutrients that may promote heart health and may help reduce the risk of some chronic diseases. For instance, the flavonoids in fruits like grapefruit may help protect the heart by reducing inflammation in the arteries. And, studies show that frequent consumption of citrus fruit, as part of a healthy diet, may help decrease the risk of certain cancers, including stomach, prostate, pancreatic, gastric and other affected organs.  A recent publication from the Nurses Health Study suggests that women who consumed the highest amount of citrus fruits per day (including grapefruit) had a decreased incidence of the most common type of stroke. 

Citrus fruits are specifically considered to be a superfood for skin care because they contain phytonutrients that function as antioxidants, protecting you from free radicals that damage skin cells and lead to signs of aging.

 

What drug interactions do people need to be aware of?

People need to be aware of interactions between prescription drugs; interactions between prescriptions & over-the-counter medicines, vitamins or supplements; interactions between drugs & foods or beverages; and interactions between drugs and illicit substances, alcohol and nicotine.  

Why does grapefruit interact with some drugs and not others?

 

There are several medications which have had interactions with grapefruit, notably Valium, some of the statins, and even Viagra.  But if you take any medicines, you should check with your doctor or pharmacist to make sure that yours isn’t on the list.  It would be unfortunate to miss out on the nutritional and taste benefits of grapefruit if you didn’t have to. 

 

Some prescription and non-prescription medications don’t mix well with grapefruit or grapefruit juice.  Grapefruit can increase the absorption of some drugs into the bloodstream which may lead to adverse affects. As a doctor, one thing I try to share with my patients is that the reason for concern only applies to some, specific  medications – not all of them. Therefore, my best advice is to check with your doctor or pharmacist and ask them about whether the specific medicines you take may have an interaction with grapefruit. Don’t make assumptions!  Chances are, you may find out that grapefruit is perfectly safe to enjoy with your medicines.  Also:  Use your doctor’s visit to also ask about whether you still need to take all your medications. It might be time to update dosages or time to discontinue a prescription.  Or, your doctor may change you to a medicine which is similar to the one you were originally taking, but is perfectly safe to enjoy with grapefruit. 

Why does grapefruit interact with some medicines?  Grapefruit is a potent inhibitor of the cytochrome P450 enzyme, which can affect the metabolism of a variety of drugs, increasing their bioavailability. In some cases, this can lead to serious elevations of some drugs in the blood-stream as well as decreases in their rates of metabolism.  The onset of the interaction can occur within 30 minutes following intake of a single glass of grapefruit juice, and the inhibition can last up to 3 days following the last administration of grapefruit juice.

 

 Are there other foods that people need to be aware of they may have negative drug interactions?

 

Other common foods & beverages people need to be careful about mixing with their medicines include alcohol, licorice, and chocolate.  Also remember that many medicines need to be taken on an empty stomach and some need to be taken with food!  These are all important questions to ask your doctor or pharmacist any time you start a new medicine. . .or now, for all your medicines, if you are uncertain about any of these issues.

 

Where can people look for more information on food-drug interactions?

The most important source of information about food-drug interactions is your doctor or pharmacist.  There is also a lot of useful information online, especially at www.cdc.gov.