Though a breakfast staple today, grapefruit were first cultivated in the 18th century, when a hybrid of Jamaican oranges and a Indonesian fruit called pomelo was grown in Jamaica. At first, it was considered too bitter to be edible, but soon it was being praised as better than oranges. The first grapefruit in the United States were grown from fruits brought to Florida in 1823. Grapefruit is now grown in Texas and Florida, as well as China, the Caribbean, and the Middle East.
Today, grapefruit is enjoyed not only for its taste but also for its health benefits—but it’s possible to take this too far. In recent years, many magazines and web sites have touted what is supposedly the "Mayo Clinic diet," which is heavy on grapefruit. This is wrong on two counts:
- Grapefruit, while healthy, is not the miracle food it is said to be. Grapefruit-based diet plans typically call for one and a half grapefruit each day, but there is no scientific evidence this will contribute to weight loss.
- The real Mayo Clinic diet is actually based not on specific foods, but on the dieter changing eating habits wholesale—it is as much psychological as nutritional. The Mayo Clinic does not endorse grapefruit-based diets, or any single-food-centered diets or diet programs with rigid menus, and in fact warns that they may be dangerous.
That’s not to say grapefruit doesn’t have health benefits. Grapefruit is full of antioxidants—substances that help protect against heart disease—such as vitamin C and lycopene. In fact, grapefruit juice has among the highest levels of antioxidant activity of any food. Eating one grapefruit per day, studies show, can lower cholesterol levels as much as 15 percent. D-limonene, another component of grapefruit, blocks the formation of carcinogens and keeps cells in the body from turning cancerous. Grapefruit also improves iron absorption.
There is a downside, however. Grapefruit juice can interfere with some medications. People taking statin drugs, antidepressants, and blood pressure medications may find that grapefruit juice heightens the effects of these medications, to the point that accidental overdose becomes a significant risk. In addition, grapefruit is high in potassium, which can be dangerous to people with kidney problems.