When it comes to vitamins and minerals, grapefruit has a lot to offer. A medium-sized grapefruit will provide 100% of your daily vitamin C requirement, plus significant amounts of vitamin A, potassium, thiamine, and folate. It also offers plenty of fiber to help with cholesterol and gut health.
Yet despite grapefruit’s myriad nutritional benefits, it should be approached with caution if you take any medications. Perhaps more than any other food, grapefruit interacts with medications at an extreme level. Grapefruit contains compounds known as furanocoumarins that destroy the ability of a key intestinal enzyme to break down medications before they enter your bloodstream. Without functioning enzymes, the bioavailability of the medication increases, meaning that far more of the drug gets absorbed. Even a small glass of juice could result in this “boosting effect,” which can take multiple days to wear off.
Decades of research have identified grapefruit interactions with medications in various drug categories, including certain statins, SSRIs, amphetamines, benzodiazepines, and many others. In total, grapefruit may react adversely with more than 85 drugs.
These interactions can be benign or dangerous, depending on the type of medication and what happens when you exceed the recommended dose, as well as other factors like how much grapefruit juice you drink and how much CYP3A4 enzyme you have in your small intestine. In severe cases, the side effects of grapefruit interaction include cardiac arrhythmia, gastrointestinal bleeding, kidney failure, and breathing problems.
To make matters more confusing, for certain classes of medications, grapefruit appears to have the opposite effect. For example, it makes the antihistamine fexofenadine (Allegra) less effective by affecting drug transporter proteins, thus preventing its absorption.
For this reason, grapefruit juice is mentioned in many medication guides and information sheets with prescription drugs, as well as Drug Fans labels for over-the-counter medicines. Some prescription drugs even come with an unmistakable “Do not take with grapefruit” warning label. It’s a good idea for individuals who take medications to discuss potential food-drug interactions with your doctor, especially if you're a fan of the sweet, tangy taste of grapefruit.
A health food with unhealthy side effects:
- The citrus industry has been working to tackle the issue by developing a grapefruit variety that won’t result in prescription drug interactions, though this is still in the early stages.
- The grapefruit originated in Barbados in the 17th century, when the sweet orange (C. × sinensis) was crossed with the pomelo (C. × maxima), another citrus fruit.
- Contrary to the claims of fad diets and wellness influencers, grapefruits are not better than any other food for increasing fat metabolism or “burning” belly fat. However, they are certainly a healthy choice for weight management, thanks to their high water and fiber content and low calorie count, at roughly 100 calories per fruit.
