These evergreen trees are usually found at around 5-6 m tall, although they can reach 13-15 m. The leaves are dark green, long (up to 150 mm) and thin. It produces 5 cm white four-petalled flowers. The fruit is yellow-skinned, largely oblate and ranges in diameter from 10-15 cm and has an acidic yellow segmented pulp. The numerous cultivars include the white grapefruit and the red, of which the 1929 US Ruby Red (of the Redblush variety) has a patent. The fruit has only become popular from the late 19th century; before that it was only grown as an ornamental plant. The US quickly became a major producer of the fruit, with orchards in Florida, Texas, Arizona, and California. In Spanish, the fruit is known as toronja or pomelo.
Grapefruits are high in pectin, a soluble fibre that helps to reduce cholestrol. Recent studies indicate that grapefruit contain substances that prevent disease. Lycopene, an antitoxidant found in pink and red fruits lower prostate cancer risk.
Grapefruits contain phenolic acids which inhibits the formation of cancer-causing nitrosamines; limonoids, terpenes and monoterpenes, which induce the production of enzymes that help prevent cancer.
They also contain bioflavonoids, which inhibit the action of hormones that promote tumour growth.
Grapefruit also helps in cases of rheumatoid arthritis, lupus and inflammatory diseases.
The fruit is rich in Vitamin C. A cup of freshly-squeezed grapefruit juice has 95 mg of vitamin C, more than 100 % of RDA.
It is also low in calories.