Scientific evidence is beginning to stack up in favor of long-held claims that grapefruit helps fight obesity, lower cholesterol and reduce the risk of certain kinds of cancer.
When we first tried grapefruit diets back in the '70s, everyone speculated that it was the ascorbic acid that somehow ate up a lot of the calories from other stuff we happened to put in our stomachs, especially the high-fat stuff, to kick-start digestion and somehow help us to lose weight.
Under the same theory, we could have lost even more by eating a lot of lemons every day - if our stomach linings and tooth enamel could have withstood the acid onslaught.
Of course, no one ever stayed on one of those old 800-calorie, grapefruit-and-egg diets long enough to prove the weight-loss claims, and none of us had ever heard of cholesterol or considered the idea of using food to fight cancer.
Now, researchers from Scripps Metabolic Research Center in San Diego and Johns Hopkins University School of Medicine in Baltimore, among others, say there is scientific evidence for some of the health claims of grapefruit growers.
Their latest research was presented in a dozen papers at a two-day symposium, "Potential Health Benefits of Citrus," at the American Chemical Society's annual meeting in August.
One Scripps Center study, which included 100 men and women, found that they lost 3.6 pounds on average when they ate half a grapefruit with each meal during a 12-week pilot study and 3.3 pounds when they drank an 8-ounce glass of grapefruit juice three times a day.
To share the benefits, you just add grapefruit to whatever diet seems to work best for what you are trying to achieve, says M. Joseph Aherns, former director of research for the Florida Department of Citrus and co-author of "The Grapefruit Solution" (Linx, $7.50 paperback).
Grapefruit is the centerpiece for what is being hailed as a "trans diet" plan that takes any diet, ranging from high-protein to low-fat and Jenny Craig to Weight Watchers and adds fresh grapefruit, grapefruit juice or one of the new dietary supplements that puts the extract of a whole half of organically grown grapefruit in a single, convenient capsule.
But ascorbic acid apparently isn't the most important active ingredient. That would be naringin, a flavonoid compound that gives grapefruit its characteristic bitter flavor and blocks the uptake of fatty acids into cells to prevent our bodies from effectively using carbohydrates.
"Grapefruit reduces your body's ability to store carbohydrates," says Daryl Thompson, a grapefruit grower and co-author of the book. Thompson and Ahrens discussed grapefruit in a recent three-way conference call.
One problem has been that naringen can slow the breakdown of certain drugs used to control high blood pressure and cholesterol. While taking drugs with grapefruit juice can increase their effectiveness, it can also cause overdoses.
But scientists from Texas A&M University are turning that problem into a benefit, according to animal studies presented at the Chemical Society meeting. They are developing a "super pill" that uses grapefruit pulp to increase the effectiveness so you can take lower doses of heart and blood pressure medications.
For more information, go to www.getyourgrapefruit.com.
Carolyn Poirot writes a weekly health column for the Fort Worth Star-Telegram. Contact her at firstname.lastname@example.org or (817) 390-7687.
(c) 2004, Fort Worth Star-Telegram. Distributed by Knight Ridder/Tribune News Service.