Grapefruit - Citrus paradisi

Detailed Description

A popular fruit with a mildly bitter taste and a surprising array of health effects

Botanical Information

Grapefruit is a citrus tree that typically grows to a height of 5–6 meters, and in rare cases up to 13–15 meters. The leaves are dark green, up to 150 mm long, narrow, and evergreen.

The trunk, leaves, and flowers closely resemble those of the orange tree. The mature fruit is slightly larger and longer than the largest orange. Grapefruit flowers have five petals and measure about 5 cm across. The fruit, known as grapefruit, has a yellow rind (exocarp) and a diameter of 10–15 cm. The inner pulp is divided into segments, and its color ranges from white and pink to deep red. The fruits also vary in sweetness.

Origin and Distribution

Grapefruit is originally from Barbados. Today, it is a globally grown fruit crop, with the largest producers being China, Brazil, Israel, Vietnam, the USA (Texas, California, Florida), Turkey, Mexico, and Spain.

Usage / Dosage

Grapefruit was officially discovered on the Caribbean island of Barbados, from where it was later imported to America (Florida) by Count Odet Philippe in 1823. It is likely a cross between a Jamaican orange (Citrus sinensis) and an Indonesian pomelo (C. maxima). While grapefruit can be grown as an ornamental plant, it became popular as a fruit only in the 19th century.

Grapefruit (also called the forbidden fruit) was first documented in 1750 by the Welsh Reverend Griffith Hughes in The Natural History of Barbados. In 1814, naturalist John Lunan used the term 'grapefruit' in his description of a similar Jamaican citrus plant. In 1830, the Jamaican variety was classified as Citrus paradisi by botanist James Macfadyen.

In Costa Rica, grapefruit is boiled to remove its sourness and made into a dessert called toronja rellena (stuffed grapefruit). In Haiti, grapefruit is primarily used for its juice (jus de Chadèque) and also to make jam (confiture de Chadèque).

Detoxification

The fruit contains high amounts of vitamins—especially vitamin C, though in lower amounts than some other fruits. Its significant fiber content can help regulate digestion and detoxify the digestive tract by trapping harmful substances.

Cardiovascular Health

Fiber, in appropriate amounts, has a beneficial effect on cholesterol and blood sugar levels and protects the vascular walls. A 2006 study published in the Journal of Agricultural and Food Chemistry found that grapefruit can reduce cholesterol levels by up to 15.5%.

In this study, 57 patients with high cholesterol who had undergone bypass surgery were followed. Half consumed grapefruit regularly after the operation, while the others did not. The grapefruit group experienced a significant reduction in cholesterol.

According to research from the American Heart Association, higher flavonoid consumption from citrus fruits may reduce the risk of ischemic stroke in women. The risk was 19% lower among those who consumed more citrus fruits.

Consuming grapefruit can reduce triglyceride levels, which are generally responsible for clogging arteries and raising cholesterol. Thanks to its high potassium and low sodium content, grapefruit is recommended for cardiac patients and those with high blood pressure.

A randomized prospective study also evaluated grapefruit’s effects on weight, blood pressure, and lipid profiles in overweight adults. For six weeks, half the participants ate fresh grapefruit three times a day with each meal. They saw moderate weight loss, lower systolic blood pressure, and significant decreases in total cholesterol and LDL (low-density lipoprotein).

Antioxidants

Grapefruit is rich in antioxidants, especially in red varieties, which are high in carotenoids and lycopene. These compounds give the fruit its color and may lower the risk of heart disease.

Thirteen flavonoids have been quantified in grapefruit peel extracts. Naringin, isonaringin, and other flavonoids showed strong cytoprotective effects in neuroblastoma cell lines.

The antioxidant sources in grapefruit (mainly vitamin C and others) can help combat free radicals, which are believed to promote cancer. A small grapefruit provides about 68.8 mg of vitamin C (recommended daily intake: 75 mg for women, 90 mg for men) and 2,270 micrograms of lycopene, another antioxidant.

A 2016 population study of nearly 50,000 men observed a link between high consumption of tomato sauce (lycopene-rich) and a lower risk of prostate cancer. Lycopene is also present in high amounts in grapefruit.

Digestive Health

Grapefruit is a source of both water and fiber. A small grapefruit weighing 200 g contains up to 182 g of water and 2.2 g of fiber. Both water and fiber help prevent constipation and support regular bowel movements, contributing to a healthy digestive tract.

Adults are generally advised to consume up to 33.6 g of fiber per day, depending on age and sex. There is evidence that a high-fiber diet may help prevent colorectal cancer.

Natural Antibiotic

Grapefruit seeds have antibiotic properties. Grapefruit seed extract is used as a prevention against infectious diseases and yeast. The extract is helpful against fungal infections, acne, cold sores, and rashes. Components in grapefruit have also been noted for significantly increasing antioxidant activity.

Diet

The fruit’s bitterness helps curb sugar cravings. Grapefruit’s low calories make it a good option for those aiming to lose weight. It also has a low glycemic index and doesn’t significantly raise blood sugar levels.

A 2013 study described grapefruit as significantly reducing the risk of type 2 diabetes. The authors also highlighted the importance of naringin content.

Cosmetics

Grapefruit extracts are used in cosmetics to remove impurities and strengthen the skin’s upper layer. They bring radiance and vitality to the skin and are beneficial for those prone to dandruff, acne, bacterial skin infections, and rashes. Vitamin C in the fruit stimulates collagen synthesis—a fundamental building block giving skin its plumpness and elasticity. Lycopene and other compounds also act antioxidatively, supporting skin health.

Grapefruit’s active compounds offer excellent antiseptic and anti-inflammatory properties. They cleanse the skin, impart freshness, and grapefruit essence gives products a refreshing, sophisticated bittersweet scent.

Drug Interactions

Grapefruits contain furanocoumarins, which influence liver enzyme activity and drug metabolism. Grapefruit consumption may affect metabolism of allergy medicines, and also interacts with blood pressure medications; its high potassium, meanwhile, supports blood pressure reduction.

Consuming grapefruit juice alongside medication can increase plasma concentrations of some drugs and decrease others, which may lead either to unwanted side effects or decreased therapeutic effects.

Active Compounds

In 200 grams of grapefruit, you’ll find 64 kcal of energy, 1.3 grams of protein, 16.2 grams of carbohydrates, 0.21 grams of fat, and 2.2 grams of fiber. Grapefruit is a significant source of vitamin C, thiamin (B1), vitamin K, and flavonoids. It also contains smaller amounts of magnesium, iron, calcium, phosphorus, folate, choline, and vitamin A. Other notable compounds include lycopene, lutein, and zeaxanthin.

Traditional Dosage

For the treatment of obesity, specific products containing grapefruit extract are used at dosages of 450–700 mg twice daily for 12 weeks. Effects were also seen from consuming half a grapefruit three times daily or taking capsules with 500 mg grapefruit extract three times daily before meals for 12 weeks.