Studies confirm that by adding grapefruit or grapefruit juice to your daily diet, you can shed those unwanted pounds.
A 12-week pilot study, led by Dr. Ken Fujioka, monitored weight and metabolic factors of the 100 men and women who participated in the Scripps Clinic “Grapefruit Diet” study. On average, participants who ate half a grapefruit with each meal lost 3.6 pounds, while those who drank a serving of grapefruit juice three times a day lost 3.3 pounds. However, many patients in the study lost more than 10 pounds.
The most important active ingredient in grapefruit that helps us to lose weight is 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.
But grapefruit confers so many more health benefits than its ability to help us shed pounds. “Grapefruit packs in lots of nutritional goodies, supplying a heaping dose of vitamin C, folic acid, and potassium — all of which protect your heart,” says Dr. Barry Sears in his book The Top 100 Zone Foods. “Pink grapefruit is relatively rich in anti-oxidants, and ruby red grapefruit provides an added bonus: lycopene, the phytochemical that helps prevent the ‘bad’ (LDL) cholesterol from oxidizing and damaging artery walls.”
As a powerful antioxidant, lycopene helps neutralize harmful free radicals, which are implicated in cancer, heart disease, macular degeneration and other age-related illnesses. The evidence for a benefit was strongest for cancers of the prostate, lung, and stomach. Data were also suggestive of a benefit for cancers of the pancreas, colon and rectum, esophagus, oral cavity, breast, and cervix.
In a Harvard study of more than 28,000 women, those with the highest blood lycopene levels were about half as likely to develop heart disease over five years as women with the lowest levels. Research also suggests that lycopene may aid blood pressure and bone health.
Grapefruit also contains pectin, a form of soluble fiber that has been shown in animal studies to slow down the progression of atherosclerosis. Pigs fed a high-cholesterol diet plus grapefruit pectin had 24 percent narrowing of their arteries, while pigs fed the high-cholesterol diet without grapefruit pectin had 45 percent narrowing.
In humans, drinking three 6-ounce glasses of grapefruit juice a day was shown to reduce the activity of an enzyme that activates cancer-causing chemicals found in tobacco smoke. In rats whose colons were injected with carcinogens, grapefruit and its isolated active compounds (apigenin, hesperidin, limonin, naringin, naringenin, nobiletin) not only increased the suicide (apoptosis) of cancer cells, but also the production of normal colon cells.