Sugar is a term for a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose characterized by a sweet flavor. In food, sugar almost exclusively refers to sucrose, which primarily comes from sugar cane and sugar beet. Other sugars are used in industrial food preparation, but are usually known by more specific names—glucose, fructose or fruit sugar, high fructose corn syrup, etc.
Sugar, because of its simpler chemical structure, was once assumed (without scientific research) to raise blood glucose levels more quickly than starch, but results from more than twenty studies demonstrate that sugar and starch cause blood glucose to rise at similar rates. This finding showed that controlling all carbohydrates is necessary for controlling blood glucose levels in diabetics, the idea behind carbohydrate counting. Many experts believe that eating too much sugar does not cause diabetes, although excessive calories from sugar can lead to obesity, which may increase the risk of diabetes. However, a 2010 meta-analysis of eleven studies involving 310,819 participants and 15,043 cases of type 2 diabetes found that "SSBs [sugar-sweetened beverages] may increase the risk of metabolic syndrome and type 2 diabetes not only through obesity but also by increasing dietary glycemic load, leading to insulin resistance, β-cell dysfunction, and inflammation."
Sugars such as sucrose are known to contribute to tooth decay, and it is impossible to develop cavities in the absence of fermentable carbohydrates. The role of starches is disputed. Lower rates of tooth decay have been seen in hereditary fructose intolerance.
Sugar has been produced in the Indian subcontinent since ancient times. It was not plentiful or cheap in early times—honey was more often used for sweetening in most parts of the world. During his campaign in India, Alexander the Great was surprised to taste the sweetening agent that was different from honey.
Originally, people chewed sugarcane raw to extract its sweetness. Sugarcane was a native of tropical South Asia and Southeast Asia. Different species likely originated in different locations with S. barberi originating in India and S. edule and S. officinarum coming from New Guinea.
However, sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store and to transport. Crystallized sugar was discovered by the time of the Imperial Guptas. Indian sailors, consumers of clarified butter and sugar, carried sugar by various trade routes. Traveling Buddhist monks brought sugar crystallization methods to China. During the reign of Harsha (r. 606–647) in North India, Indian envoys in Tang China taught sugarcane cultivation methods after Emperor Taizong of Tang (r. 626–649) made his interest in sugar known, and China soon established its first sugarcane cultivation in the seventh century. Chinese documents confirm at least two missions to India, initiated in 647 AD, for obtaining technology for sugar-refining. In South Asia, the Middle East and China, sugar became a staple of cooking and desserts.
During the Muslim Agricultural Revolution, Arab entrepreneurs adopted sugar production techniques from India and then refined and transformed them into a large-scale industry. Arabs set up the first cane sugar mills, refineries, factories and plantations. The Arabs and Berbers spread the cultivation of sugar throughout the Arab Empire and across much of the Old World, including Western Europe after they conquered the Iberian Peninsula in the eighth century AD. Ponting traces the spread of the cultivation of sugarcane from its introduction into Mesopotamia, then the Levant and the islands of the eastern Mediterranean, especially Cyprus, by the 10th century. He also notes that it spread along the coast of East Africa to reach Zanzibar.
Crusaders brought sugar home with them to Europe after their campaigns in the Holy Land, where they encountered caravans carrying "sweet salt". Early in the 12th century, Venice acquired some villages near Tyre and set up estates to produce sugar for export to Europe, where it supplemented honey as the only other available sweetener. Crusade chronicler William of Tyre, writing in the late 12th century, described sugar as "very necessary for the use and health of mankind".
In August 1492 Christopher Columbus stopped at La Gomera in the Canary Islands, for wine and water, intending to stay only four days. He became romantically involved with the Governor of the island, Beatriz de Bobadilla y Ossorio, and stayed a month. When he finally sailed she gave him cuttings of sugarcane, which became the first to reach the New World.
The etymology reflects the spread of the commodity. The English word "sugar" originates from the Arabic word سكر sukkar, itself derived from Sanskrit शर्करा sharkara. It most probably came to England by way of Italian merchants. The contemporary Italian word is zucchero, whereas the Spanish and Portuguese words, azúcar and açúcar respectively, have kept a trace of the Arabic definite article. The Old French word is zuchre - contemporary French sucre. The earliest Greek word attested is σάκχαρη [sákχari]. A satisfactory pedigree explaining the spread of the word has yet to be done. Note that the English word jaggery (meaning "coarse brown Indian sugar") has similar ultimate etymological origins (presumably in Sanskrit).
The term sugar usually refers to sucrose, which is also called "table sugar" or "saccharose." Sucrose is a white crystalline disaccharide. It is often obtained from sugar cane or sugar beet. Sucrose is the most popular of the various sugars for flavoring, as well as properties (such as mouthfeel, preservation, and texture) of beverages and food.