Tart and tangy with an underlying sweetness, grapefruit has a juiciness that rivals that of the ever-popular orange and sparkles with many of the same health-promoting benefits. Although available throughout the year, they are in season and at their best from winter through early spring. Grapefruits usually range in diameter from four to six inches and include both seed and seedless and pink and white varieties. The wonderful flavor of a grapefruit is like paradise as is expressed by its Latin name, Citrus paradisi.
Grapefruit may be the less favored citrus choice when compared to its sweeter cousin, the orange, but grapefruit sparkles with health promoting compounds that may help:
- fight cold symptoms
- prevent certain forms of cancer
- prevent heart disease
Grapefruit is an excellent source of vitamin C, a vitamin that helps to support the immune system. Vitamin C-rich foods like grapefruit may help reduce cold symptoms or severity of cold symptoms. Over 20 scientific studies have suggested that vitamin C is a cold-fighter. Vitamin C also prevents the free radical damage that triggers the inflammatory cascade, and is, therefore, also associated with reduced severity of inflammatory conditions, such as asthma, osteoarthritis, and rheumatoid arthritis. As free radicals can oxidize cholesterol and lead to plaques that may rupture causing heart attacks or stroke, vitamin C is beneficial for promoting cardiovascular health. Owing to the multitude of vitamin C's health benefits, it is not surprising that research has shown that consumption of vegetables and fruits high in this nutrient is associated with a reduced risk of death from all causes, including heart disease, stroke and cancer.
Protection against Lung and Colon Cancer: Not only are grapefruit rich in vitamin C, but new research presented August 2004 at the 228th National Meeting of the American Chemical Society provides two more reasons to drink grapefruit juice: protection against lung and colon cancer. 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. Researchers also confirmed that grapefruit may help prevent weight gain by lowering insulin levels.
New insight into how grapefruit protects against cancer: Grapefruit juice significantly increases the production and activity of liver detoxification enzymes responsible for preparing toxic compounds for elimination from the body. The liver clears out toxins, including carcinogens, using a two step process called Phase I and Phase II detoxification. In the first part of this process, Phase I, enzymes belonging to the cytochrome P450 family, work on the toxin to make it more attractive to enzymes involved in the second part of the process, Phase II. Unfortunately, the action of Phase I enzymes often renders the toxin not only more attractive to Phase II enzymes, but even more dangerous, and some foods contain compounds that only increase the activity of Phase I without also turning up Phase II. Grapefruit increases the activity not only of the Phase I enzyme CYP1A1, but also that of NAD(P)H:quinone reductase 1, a Phase II detoxification enzyme that protects cells against oxidative stress and toxic quinines.
The end result: grapefruit works in both Phase I and Phase II to enhance the liver's ability to remove cancer-causing toxins.
Lycopene - The rich pink and red colors of grapefruit are due to Lycopene, a carotenoid phytochemical. Lycopene appears to have anti-tumor activity. Among the common dietary carotenoids, Lycopene has the highest capacity to help fight oxygen free radicals, which are compounds that can damage cells.
Limonoids - Phytochemicals in grapefruit called limonoids inhibit tumor formation by promoting the formation of glutathione-S-transferase, a detoxifying enzyme. This enzyme sparks a reaction in the liver that helps to make toxic compounds more water soluble for excretion from the body. Pulp of citrus fruits like grapefruit contain glucarates, compounds which may help prevent breast cancer.
Grapefruit contains pectin, a form of soluble fiber that forms a gel-like substance in the intestinal tract that can trap fats like cholesterol. In animal studies, grapefruit pectin inhibited the formation of atherosclerosis. Animals fed a high-cholesterol diet plus grapefruit pectin had 24% narrowing of their arteries, while animals fed only the high-cholesterol diet had 45% narrowing.
Prevent Kidney Stones
Want to reduce your risk of calcium oxalate kidney stones? Drink grapefruit juice. A study published in the August 2003 issue of the British Journal of Nutrition found that when women drank ½ to 1 litre of grapefruit, apple or orange juice daily, their urinary pH value and citric acid excretion increased, significantly dropping their risk of forming calcium oxalate stones.
Protection against Macular Degeneration
Your mother may have told you carrots would keep your eyes bright as a child, but as an adult, it looks like fruit is even more important for keeping your sight. Data reported in a study published in the June 2004 issue of the Archives of Opthamology indicates that eating 3 or more servings of fruit per day may lower your risk of age-related macular degeneration (ARMD), the primary cause of vision loss in older adults, by 36%, compared to persons who consume less than 1.5 servings of fruit daily. In this study, which involved 77,562 women and 40,866 men, researchers evaluated the effect of study participants' consumption of fruits; vegetables; the antioxidant vitamins A, C, and E; and carotenoids on the development of early ARMD or neovascular ARM, a more severe form of the illness associated with vision loss. Food intake information was collected periodically for up to 18 years for women and 12 years for men. While, surprisingly, intakes of vegetables, antioxidant vitamins and carotenoids were not strongly related to incidence of either form of ARM, fruit intake was definitely protective against the severe form of this vision-destroying disease. Three servings of fruit may sound like a lot to eat each day, but grapefruit can help you reach this goal. Try starting your day with a half grapefruit, add grapefruit sections to your green salads, or for an elegant dessert, spread a little honey over a half grapefruit and broil for 1-2 minutes.
The grapefruit is a large citrus fruit related to the orange, lemon, ugli and pomelo. Grapefruits are categorized as white, pink or ruby. However, this terminology doesn't reflect their skin color, which is either yellow or pinkish-yellow, but rather describes the color of their flesh. Grapefruits usually range in diameter from four to six inches, with some varieties featuring seeds while others are seedless. The wonderful flavor of a grapefruit is like paradise, just as its Latin name Citrus paradisi connotes. It is juicy, tart and tangy with an underlying sweetness that weaves throughout.
Grapefruits have a rather recent history, having been discovered in Barbados in the 18th century. Many botanists think the grapefruit was actually the result of a natural cross breeding which occurred between the orange and the pomelo, a citrus fruit that was brought from Indonesia to Barbados in the 17th century. The resulting fruit was given the name “grapefruit” in 1814 in Jamaica, a name which reflects the way it's arranged when it grows – hanging in
clusters just like grapes. Grapefruit trees were planted in Florida in the early 19th century, although they did not become a viable commercial crop until later that century. Florida is still a major producer of grapefruits, as is California, Arizona and Texas. Other countries that produce grapefruits commercially include Israel, South Africa and Brazil.
Tips for preparing grapefruit:
Grapefruits should be rinsed under cool water before consuming, even though you will probably not be eating the peel, since cutting into an unwashed fruit may transfer dirt or bacteria that may reside on the skin’s surface to the edible flesh. Grapefruits are usually eaten fresh by slicing the fruit horizontally and scooping out sections of the halves with a spoon. To separate the
flesh from the membrane you can either cut it with a sharp knife, a special curved-blade grapefruit knife, or a serrated grapefruit spoon. If there are seeds, you can remove them with your spoon before you eat. Grapefruits can also be eaten like oranges. You can peel them with your hands or with a knife. If choosing the latter method, starting at the top, make a vertical incision that runs downward and then back up to the top on the other side and then repeat so that there will be four sections of similar size. Be careful to only cut through skin and not into the membrane. The skin can then be peeled back with your hands or with the knife. The membranes can be separated, as you would do to an orange eaten in this manner. Another way to serve grapefruit is to peel and slice them.
A few quick serving ideas:
- Grapefruit sections add a tangy spark to green salads.
- Instead of your morning glass of OJ, have a glass of grapefruit juice.
- Combine diced grapefruit with cilantro and chili peppers to make a unique salsa.
- To enjoy a salad with a tropical flair, combine chopped grapefruit pieces, cooked shrimp and avocadoes and serve on a bed of romaine lettuce.
Grapefruit and Drug Interactions
Check with your healthcare practitioner if you're taking pharmaceutical drugs with grapefruit juice. Certain pharmaceutical drugs combined with grapefruit juice become more potent. Compounds in grapefruit juice, including naringenin, slow the normal detoxification and metabolism processes in the intestines and liver, which hinders the body's ability to breakdown and eliminate these drugs. These interactive drugs include the immunosuppressent cyclosporine and calcium channel blocker drugs, such as felodipine, nifedipine and verapamil. Other drugs enhanced by grapefruit juice are the antihistamine terfenadine, the hormone estradiol and the antiviral agent saquinavir. Research also indicates that individuals taking statin drugs should avoid grapefruit. Grapefruit increases the amount of statin drug that reaches the general circulation in two ways. First, grapefruit contains a compound called naringenin, which inactivates an enzyme (cytochrome P450 3A4) in the small intestine that metabolizes statin drugs. Secondly, grapefruit also inhibits P-glycoprotein, a carrier molecule produced in the intestinal wall that would normally transport the statin drug back to the gut. The end result of these two mechanisms is that much more of the statin drug enters the systemic circulation than would normally be the case, leading to a build up in statin levels that can be quite dangerous, and may trigger a rare but serious statin-associated disease called rhabdomyolysis. Rhaddomyolysis affects muscle tissue, usually causing temporary paralysis or weakness, unless the muscle is severely injured. (March 25, 2004)
The following chart shows the nutrients for which this food is either an excellent, very good or good source. Next to the nutrient name you will find the following information: the amount of the nutrient that is included in the noted serving of this food; the %Daily Value (DV) that that amount represents (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and, the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. For more detailed information on our Food and Recipe Rating System.
Nutrient Amount DV
Density World's Healthiest
vitamin C 66.00 mg 110.0 33.0 excellent
vitamin A 750.00 IU 15.0 4.5 very good
dietary fiber 2.70 g 10.8 3.2 good
potassium 230.00 mg 6.6 2.0 good