The sweet orange does not occur in the wild. It is believed to have been first cultivated in southern China, northeastern India, or perhaps southeastern Asia (formerly Indochina). The Persian orange, grown widely in southern Europe after its introduction to Italy in the 11th century, was bitter. It was used primarily for medicinal purposes. Italian traders might have introduced it to the Mediterranean area after 1450. Portuguese navigators have also been credited with bringing orange trees to the Mediterranean region around 1500. After introduction of the sweet orange, it was quickly adopted as an edible fruit; it was so highly regarded that wealthy persons grew oranges in private conservatories, called orangeries. Certainly by 1646 it was well known in Europe.
In some South East Indo-European languages the orange was named after Portugal, which was formerly the main source of imports of sweet oranges. Examples are Bulgarian portokal портокал, Greek portokali πορτοκάλι, Persian portaghal پرتقال, Albanian portokall, Macedonian portokal портокал, and Romanian portocală. In Italian the word portogallo to refer to the orange fruit is dialectal. It means literally "Portugal". Similar words are in common use in most Italian dialects across the whole country. Related names can also be found in other languages: Turkish portakal, Arabic al-burtuqal البرتقال, Amharic birtukan, and Georgian p'ort'oxali ფორთოხალი, Portuguese, Spanish, Arab, and Dutch sailors planted citrus trees along trade routes to prevent scurvy. On his second voyage in 1493, Christopher Columbus took the seeds of oranges, lemons and citrons to Haiti and the Caribbean. They were introduced in Florida (along with lemons) in 1513 by Spanish explorer Juan Ponce de León, to California by the Franciscans in the 18th century, and were introduced to Hawaii in 1792.
Spaniards undoubtedly introduced the sweet orange into South America and Mexico in the mid-1500s, and probably the French took it to Louisiana. It was from New Orleans that seeds were obtained and distributed in Florida about 1872 and many orange groves were established by grafting the sweet orange onto sour orange rootstocks. Arizona received the orange tree with the founding of missions between 1707 and 1710. The orange was brought to San Diego, California, by those who built the first mission there in 1769. An orchard was planted at the San Gabriel Mission around 1804. A commercial orchard was established in 1841 on a site that is now a part of Los Angeles. In 1781, a surgeon and naturalist on the ship Discovery collected orange seeds in South Africa, grew seedlings on board and presented them to tribal chiefs in the Hawaiian Islands on arrival in 1792. In time, the orange became commonly grown throughout Hawaii, but was virtually abandoned after the arrival of the Mediterranean fruit fly, and the fruit is now imported from the United States mainland. - Fruits of Warm Climates
Nutrients in oranges are plentiful and diverse. The fruit is low in calories, contains no saturated fats or cholesterol, but is rich in dietary fiber, pectin, which is very effective in persons with excess body weight. Pectin, by its action as bulk laxative, helps to protect the mucous membrane of the colon by decreasing its exposure time to toxic substances as well as by binding to cancer causing chemicals in the colon. Pectin has also been shown to reduce blood cholesterol levels by decreasing its re-absorption in the colon by binding to bile acids in the colon. - Nutrition & You
In recent research studies, the healing properties of oranges have been associated with a wide variety of phytonutrient compounds. These phytonutrients include citrus flavanones (types of flavonoids that include the molecules hesperetin and naringenin), anthocyanins, hydroxycinnamic acids, and a variety of polyphenols. When these phytonutrients are studied in combination with oranges "vitamin C, the significant antioxidant properties of this fruit are understandable. But it is yet another flavanone in oranges, the herperidin molecule, which has been singled out in phytonutrient research on oranges. Arguably, the most important flavanone in oranges, herperidin has been shown to lower high blood pressure as well as cholesterol in animal studies, and to have strong anti-inflammatory properties. Importantly, most of this phytonutrient is found in the peel and inner white pulp of the orange, rather than in its liquid orange center, so this beneficial compound is too often removed by the processing of oranges into juice. - Oranges, Worlds Healthiest Foods
Raw orange peel has 1.5 g of protein and is a source of potassium, riboflavin and vitamin A. Oranges are considered a source of calcium, which contributes to bone and tooth health. According to Purdue University Horticulture and Landscape Architecture, 100 g of edible orange fruit contains 40 mg of calcium, while the same amount of orange peel has 161 mg of calcium. - Rose Welton, LiveStrong
Folic acid in Oranges is one B vitamin that promotes good cardiovascular health. Folic acid helps to lower blood concentrations of homocysteine. Homocysteine is an amino acid by-product of protein metabolism that plays a major role in cardiovascular disease. High levels of homocysteine can result in a heart attack. Homocysteine builds up in the circulatory system damaging the blood vessels. The combination of folic acid and other B vitamins can lower the risk of a heart attack or stroke, by removing homocysteine from the circulatory system. - Catalina Andrade, Suite 101
Regularly consuming vitamin C retards the development of hardening of the arteries. An orange a day is sufficient for a man to keep his sperm healthy. Vitamin C, an anti-oxidant, protects sperm from genetic damage that may cause a birth defect. A high intake of flavonoids and vitamin C has been known to halve the risk of heart diseases. - Juicing For Health, Oranges