Grapefruits (Citrus × paradisi) are subtropical fruits. They belong to the genus Citrus, which also includes lemons, oranges, tangerines (mandarin oranges), and pomelos. The fruit is a modified berry with tough, leathery rind called a hesperidium. As with other citrus fruits, grapefruit peels contain many volatile oil glands in pits. Their inner flesh is composed of eight to ten segments, called carpels, made up of juice-filled vesicles that are actually specialized hair cells. The flesh and juice are acidic, varying in color depending on the cultivars, which include white, pink, and red pulps of varying sweetness (generally, the redder varieties are sweeter). Along with other citrus fruits, they are members of the Rutaceae family, which is one of only two plant families that produce a class of phytochemicals called limonoids. Limonoids mainly deter animals from eating citrus plants. They are responsible for the bitter taste of citrus peels, and, when consumed by animals, act as a growth inhibitor, and even as a natural insecticide.

Grapefruits are the only citrus fruits that did not originate in Southeast Asia. They are the result of an 18th-century hybrid of an Indonesian pomelo (citrus grandis), and a sweet orange (citrus x sinensis) that emerged in Barbados. The Reverend Griffith Hughes (1707–c.1758), a Welsh minister and naturalist, first described the grapefruit, which he called “The Forbidden Fruit,” in The Natural History of Barbados, which was published in London in 1750. Grapefruits arrived in Jamaica by 1789.

It wasn’t until 1814 that a Jamaican farmer called the fruit “grapefruit,” reportedly because he thought it grew in grape-like clusters. In 1823, Count Odette Phillipe brought the seeds from the Bahamas to Safety Harbor near Tampa, Florida. The seeds from those first plants thrived and produced flavorful, seedy fruit, which eventually became the Duncan grapefruit. In the 1860s, a nurseryman named C. M. Marsh developed a seedless variety of grapefruit that bore his name. In 1870, John A. MacDonald noticed an unusual tree near his home in Orange County, Florida. He bought all the fruit from the tree. Soon after, he established the first grapefruit nursery from the seeds of those fruits. In 1885, Florida’s first shipment of grapefruits to New York and Philadelphia was the beginning of a serious commercial grapefruit industry. By the late 19th century, grapefruit trees were growing in southern Texas. One tree froze repeatedly during some very cold Texas winters, but survived to produce fruit.

Florida developed into a major commercial center with its Duncan and Marsh varieties of grapefruit. The Duncans were most used for canning. In the early years of the 20th century, new grapefruit varieties, including those with pink and red flesh, were developed and became popular in the northern states. The pink varieties discolored when canned, so they needed to be shipped fresh. As early as 1910 farmers were successfully growing grapefruits in the Rio Grande Valley of Texas, and in Arizona and California. In 1929 a Texas citrus grower discovered a red grapefruit growing on a tree that had been producing pink grapefruits. That mutation became a new cultivar named Ruby Red that was the first grapefruit granted a U.S. patent. During the Great Depression of the 1930s, destitute American families could use food stamps to get free grapefruits, along with other citrus fruits. Families weren’t quite sure whether grapefruits were supposed to be cooked or eaten raw. Apparently, some families complained that they had cooked the grapefruits for several hours and they were still too tough to eat.

All that changed during the 1940’s, when grapefruits became a household favorite across the United States. People cut grapefruits in half, loosened its sections with a special knife with a serrated, curved blade, and topped the grapefruit with a sprinkle of sugar and sometimes half a maraschino cherry for a new breakfast favorite. Many families owned a set of grapefruit spoons that had pointed tips and serrated edges for separating the flesh from the membranes. A popular salad combined grapefruit and orange sections tossed with lettuce and onion rings and topped with a French, poppyseed, or honey-mustard dressing. Fresh grapefruit, along with canned grapefruit sections and grapefruit juice, were shipped throughout the United States and exported to other countries. Jamaica, Trinidad, Israel, and several South American nations began cultivating grapefruit commercially.

During the 1950s and 1960s, fruit cups of canned grapefruit and orange sections in sweet syrup with a maraschino cherry on top became common at fancy restaurants and weddings. Gelatin molds featured embedded chopped grapefruit and orange sections. Broiled grapefruit topped with brown sugar was popular as an appetizer or dessert. The English enjoyed grapefruit marmalade, and some people even candied the grapefruit peels.

The grapefruit diet, which was around at least since the 1930s, became a fad in the 1970s. It claimed that a person could lose 10 pounds in 12 days by consuming grapefruits or grapefruit juice with every meal, supposedly because the grapefruit enzymes would burn fat away. There is no evidence that the diet worked. 

The Texas Red grapefruit became the official state fruit of Texas in 1993.

Today Mexico exports grapefruits to the United States, Canada, and Japan. In Asia, pomelos are still much more prevalent than grapefruits. The United States currently produces 41 percent of the world’s grapefruit and consumes more than other countries. Florida, the state where grapefruit was first grown, is still the largest producer with Texas following close behind. California and Arizona also have thriving commercial grapefruit orchards.

Commercial growers focus on developing fruits that are larger, more uniform in size, and with attractive color. Unfortunately, flavor is often sacrificed for appearance. The heirloom varieties were reportedly tastier than today’s new cultivars but are only used for canning grapefruit juice.

Grapefruit can:

1. Support your immune system. Grapefruit is an excellent source of vitamin C, which helps support your immune system and may help reduce the severity of cold symptoms. The tannic acid in grapefruits is a powerful antibacterial that can prevent diarrhea. Kaempferol in grapefruit has antimicrobial, analgesic, and antiallergic activities. Narirutin in grapefruits reduces reduces hepatitis C virus production by infected liver cells.
2. Fight free radicals. Vitamin C also fights free radicals, which are compounds that can damage cells. Limonin, nomilin, and  nomilinic acid in grapefruits also act as active antioxidants. Beta-crpytoxanthin in grapefruit protects your cells from the damaging effects of free radicals, provides a source of vitamin A, and reduces your risk of lung cancer, rheumatoid arthritis, and inflammatory polyarthritis. The tannic acid in grapefruits is a powerful antioxidant that may prevent Alzheimer’s disease, cancer, and diabetes. Kaempferol in grapefruit is a strong antioxidant that helps to prevent oxidative damage of your cells, lipids, and DNA. Naringenin in grapefruit has antioxidant effects, and may be useful in reducing oxidative damage to DNA. Narirutin in grapefruits reduces oxidative damage to DNA. Red and pink grapefruits also contain lycopene. Among the common carotenoids, lycopene has the highest capacity to help fight oxygen free radicals. 
3. Fight chronic inflammation. Besides leading to heart disease and cancer,  free radicals can trigger an inflammatory cascade. Grapefruits are therefore also associated with reduced severity of inflammatory conditions, such as asthma, osteoarthritis, and rheumatoid arthritis. Beta-crpytoxanthin in grapefruit reduces your risk of rheumatoid arthritis, and inflammatory polyarthritis. Campesterol in grapefruit prevents the absorption of LDL cholesterol, balances blood cholesterol levels, and displays anti-inflammatory properties, which may make it beneficial for arthritis and cardiovascular diseases, among other health conditions. Kaempferol and naringenin in grapefruit also have anti-inflammatory activities.
4. Prevent cancer. Grapefruit contains the phytochemicals apigenin, hesperidin, limonin, naringin, naringenin, and nobiletin, which not only increased the self-destruction (apoptosis) of cancer cells, but also the production of normal colon cells. Phytochemicals called limonoids in grapefruits, including limonin, nomilin, and  nomilinic acid, prevent the breakdown of cell DNA, fight cancers of the mouth, skin, lung, breast, stomach, and colon, and are are potent anti-carcinogens that may prevent cancerous cells from proliferating and inhibit tumor formation by promoting the formation of glutathione-S-transferase, a detoxifying enzyme. This enzyme sparks a reaction in your liver that helps to make toxic compounds more water-soluble so that they can be excreted from your body. Your body can readily absorb and use a very long-acting limonoid called limonin that is present in grapefruits and other citrus fruits in about the same amount as vitamin C. In citrus fruits, limonin is present in the form of limonin glucoside, in which limonin is attached to a sugar (glucose) molecule. Your body easily digests this compound, separating off the sugar and releasing limonin. Grapefruit pulp, like other citrus pulp, contains glucarates, compounds that may help prevent breast cancer. Beta-crpytoxanthin in grapefruit protects your cells from the damaging effects of free radicals, and reduces your risk of lung cancer. The tannic acid in grapefruits is a powerful antimutagenic, antioxidant, and antitoxic that may prevent cancer. Kaempferol in grapefruit is a strong antioxidant that helps to prevent oxidative damage of your cells, lipids, and DNA, and acts as a chemopreventive agent, which means that it inhibits the formation of cancer cells. Narirutin in grapefruits reduces oxidative damage to DNA. Naringenin, a flavonoid concentrated in grapefruit, helps repair damaged DNA in human prostate cancer cells. The risk of prostate cancer, the most commonly diagnosed cancer in men in the United States, increases with age, because the older you become, the more times your cells have divided and the greater the chance for DNA mutations to occur. DNA repair is one of your body’s primary defense mechanisms against the development of cancer, because it removes potentially cancer-causing mutations in cells. Naringenin helps restore damaged DNA by inducing two enzymes that repair DNA during the replication stage. These enzymes, 8-oxoguanine-DNA glycosylase 1 (hOGG1), and DNA polymerase beta (DNA poly beta), are both involved in the DNA base excision repair (BER) pathway. Unlike many other cancers, prostate cancer is slow-growing initially and often remains undetectable for a long time. Enjoying grapefruit regularly may be one way to prevent its progression by repairing the damaged DNA in prostate cells, thus preventing them from becoming cancerous. The lycopene in red and pink grapefruit also seems to have have anti-tumor activity, particularly against prostate cancer. 
5. Promote cardiovascular health. Because free radicals can oxidize cholesterol and lead to plaques that may rupture causing heart attacks or stroke, the vitamin C in grapefruit promotes cardiovascular health. Limonin, nomilin, and  nomilinic acid in grapefruits may reduce cholesterol, and inhibit the production of cholesterol compounds in your liver. Apolipoprotein B (ApoB) is a structural protein that is part of the low-density lipoprotein (LDL or “bad”) cholesterol molecule and is needed for LDL production, transport, and binding. When exposed to limonin in grapefruits, human liver cells produce less ApoB, which translates to lower levels of LDL cholesterol. Campesterol in grapefruit prevents the absorption of LDL cholesterol, and balances blood cholesterol levels. Kaempferol in grapefruit is a strong antioxidant that helps to prevent oxidative damage of your cells, lipids, and DNA, and seems to prevent arteriosclerosis by inhibiting the oxidation of LDL and the formation of platelets in your blood. Hesperidin in grapefruit strengthens your blood vessels. Naringenin in grapefruit may be useful in preventing heart disease. Narirutin in grapefruits inhibits the secretion of very-low-density lipoprotein and lowers plasma and hepatic cholesterol concentrations. Grapefruit also contains pectin, a form of soluble fiber that slows down the progression of atherosclerosis. Both white and red grapefruit can reduce blood levels of LDL cholesterol, but red grapefruit was more than twice as effective, and lowers triglycerides as well. In addition, while both white and red grapefruits significantly improved blood levels of protective antioxidants, red grapefruit’s better performance may be due to an as yet unknown antioxidant compound or the synergistic effects of its phytochemicals, including lycopene. 
6. Prevent kidney stones. Grapefruit increases urinary pH value and citric acid excretion, significantly decreasing your risk of forming calcium oxalate stones.
7. Prevent weight gain. Grapefruit may help prevent weight gain by lowering insulin levels. Naringenin in grapefruit may be useful in preventing obesity. Narirutin in grapefruits fights the obesity effects of a high-fat diet.

Both white and red grapefruits are comparable in their content of fiber, phenolic and ascorbic acids, and the flavonoid, naringinen. Red grapefruit contains more bioactive compounds and total polyphenols, total flavonoids and anthocyanins than white. In addition, pink and red grapefruits provide lycopene, a carotenoid phytochemical that can reduce men’s risk of developing prostate cancer.

Nutrients in 100 Grams of White Grapefruit

Nutrient	Amount	Daily Value
vitamin C	33.3 mg	56%
potassium	148 mg	4%
fiber	1.1 g	4%
carbohydrates	8.4 g	3%
pantothenic acid	0.3 mg	3%
copper	0.05 µg	3%
folate	10 µg	2%
choline	7.7 mg	2%
vitamin B6	0.043 mg	2%
thiamine	0.037 mg	2%
Calories	33	2%
vitamin A	33 IU	1%
calcium	12 mg	1%
protein	0.7 g	1%
niacin	0.3 mg	1%
vitamin E	0.1 mg	1%
riboflavin	0.02 mg	1%
magnesium	0.013 mg	1%
manganese	0.013 mg	1%
zinc	0.1 mg	0.7%
iron	0.1 mg	0.55%
fat	0.1 g	0.15%
sodium	0 mg	0%
cholesterol	0 mg	0%
vitamin K	0 µg	0%
carotene-ß	14 µg
lutein-zeaxanthin	10 µg
carotene-α	8 µg
crypto-xanthin-β	3 µg

Grapefruit is harvested when fully ripened and is available in the supermarkets year round; however, its peak season is January through June. Grapefruits should feel solid and heavy for their size, as this usually indicates thin skins and a higher concentration of juicy flesh. Grapefruits should be shiny,smooth, firm, yet slightly springy when gentle pressure is applied. Skin discoloration, scratches or scales do not affect the taste or texture. While chilled grapefruits do not have an apparent fragrance, those kept at room temperature should have a subtly sweet aroma. Avoid grapefruits that have soft areas, large brown spots, dull or dry-looking skin, or overly rough or wrinkled skin. 

Grapefruits can keep a week or slightly longer at room temperatures of 65 degrees or higher. For longer storage, about six to eight weeks, store the fruits in the fruit and vegetable keeper of the refrigerator. To consume grapefruit at optimum flavor, keep it at room temperature at least 2 hours before eating.

Commercial grapefruit is often washed and waxed before coming to market to retard moisture loss and lengthen shelf life. Frequently, fumigants and fungicides are applied to the grapefruit to prevent spoilage. Wash grapefruit thoroughly before cutting into the flesh.

Grapefruit has a sour to semi-sweet taste. Here are some ideas for enjoying it:

• Enjoy the traditional half grapefruit sectioned with a grapefruit knife as a breakfast, lunch, or dinner starter. If the grapefruit’s bitter notes are not to your liking, sweeten it with a spoonful agave nectar, maple syrup, or date sugar.
• When fresh grapefruit is not available, frozen grapefruit juice is an excellent substitute, either alone, or blended with the juices of other fruits such as apples, pears, and oranges. You can prepare a refreshing beverage or smoothie in the blender.
• Make a salad with grapefruit sections, either pink or white, along with orange and tangerine sections, over spinach or baby greens and some crunchy vegetables like kohlrabi, celery, sweet onions, or jicama. Add a creamy avocado dressing or one with a hint of fruity sweetness.
• When citrus is in season, toss the different varieties together in a fruit cup, a beverage, or a salad. Include white, pink, and red grapefruit for more color variety.
• Make a grapefruit spritzer with sweet grapefruit juice and seltzer.
• Prepare sorbet with grapefruit juice. Thin slightly with water, sweeten to taste, and freeze about 2 or 3 hours. Remove and stir, and return to the freezer until ready to serve.
• Enhance your mixed green salad with an oil-free salad dressing made from fresh pink grapefruit. Add sweet fruits such as chopped apples, pears, or raisins to balance the acidity of the grapefruit.

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This blog uses the latest nutritional data available from the USDA (United States Department of Agriculture), and the FDA (United States Food and Drug Administration), as well as nutritional data provided by food growers and manufacturers about their products. We believe the information on this blog to be accurate. However, we are not responsible for typographical or other errors. Nutrition information for recipes is calculated by Living Cookbook based on the ingredients in each recipe based on statistical averages. Nutrition may vary based on methods of preparation, origin and freshness of ingredients, and other factors.

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