Unlike other water-soluble vitamins, vitamin C, or ascorbic acid, doesn't appear to act either as a catalyst or as a coenzyme. Its primary role is a major one, however: regulating the formation of collagen, a protein that makes up the connective tissue found in skin, bones, cartilage, teeth, muscles and the walls of blood vessels. As an important antioxidant, vitamin C also helps protect vitamin A, vitamin E and various fatty acids from the damage caused by excessive oxidation.
Because little of vitamin C is stored in the body, a daily dietary source is necessary. The vitamin is found almost exclusively in fruits and vegetables, particularly in citrus fruits such as oranges and lemons (interestingly, most animals synthesize their own vitamin C. Only primates, guinea pigs and a few fairly exotic creatures--such as the Indian fruit bat--need to get the vitamin from food). Today cereals, infant formulas and other foods are often supplemented with vitamin C, so that a serious deficiency is quite rare.
In past centuries, however—and even in the first decade of the twentieth century--vitamin C deficiencies were not only common, especially during the winter months, but occasionally lasted long enough to produce scurvy, a debilitating and potentially fatal disease. A prolonged lack of vitamin C, after all, leads to problems with the body's connective tissues. This means that, early in scurvy, the walls of the smaller blood vessels begin to rupture. The patient's gums bleed and small hemorrhagic spots appear on the skin. In later stages, teeth loosen and fall out, bones weaken, joints become swollen and painful, wounds fail to heal (connective tissue is needed to repair cuts in the skin), anemia may develop and, unless the disease is checked, death results.
The discovery of vitamin C came after centuries of the search for a scurvy cure. The disease was often described by historians since it tended to plague armies, navies, explorers, and even crusaders. Many of the crewmen who sailed with Vasco da Gama (1469-1524) in 1498 and with Ferdinand Magellan (1480-1521) in 1519, for example, were killed, not by savage storms or hostile natives, but by the scurvy that developed after long months eating the typical navy diet of dry biscuits and salted beef. Fortunately for later researchers, historians also reported on the folk remedies that seemed to keep the terrible disease at bay. For instance, when Jacques Cartier (1491-1557) arrived in Newfoundland in 1536 with hundreds of scurvy-ridden crewmen, friendly Indians advised him to give his men an extract of needles from local trees (thought to be white cedar, spruce or sassafras.) Cartier took their advice and promptly cured most of his men. During that same century, other writers mentioned cloudberries, various vegetables and even citrus fruits as a remedy for scurvy.
Nevertheless, the Scottish naval surgeon, James Lind (1716-1794), is generally credited with being the first to discover the cure for scurvy. In 1747--shortly after the four-year voyage of Admiral George Anson (1697-1762), during which over a thousand sailors died mostly from scurvy--Lind began his own investigations into the disease. After reading numerous historical accounts, Lind realized that scurvy almost invariably broke out among people whose diet, for one reason or another, had become severely limited. He therefore took a ten-week voyage during which he treated stricken sailors with various foods--and found that citrus fruits effected the fastest and most dramatic cures. Although Lind published his Treatise on the Scurvy in 1753, it wasn't until almost a half-century later, in 1795, that the admiralty began prescribing daily doses of lime juice for all British sailors (as a result, British sailors became known as limeys). Scurvy promptly diminished, but only in the British navy.
For the most part, the civilized world continued to resist the notion that scurvy might be due to a dietary deficiency. In 1907, however, two Norwegian biochemists, Axel Holst (1861-1931) and Theodore Frolich, proved conclusively that a scurvy-like condition could be produced in the guinea pig by restricting certain foods and cured by restoring those foods. The stage was then set for the eventual discovery of a new vitamin. Between 1910 and 1920, Zilva and his associates worked at isolating the elusive anti-scurvy substance in various foods and found one substance that appeared to be effective. However, the actual isolation of ascorbic acid was accomplished a few years later, in 1928, by two independent teams of researchers. One of the teams was headed by Albert Szent-Györgyi, who extracted a substance from cabbage, oranges, paprikas and adrenal glands which he named hexuronic acid. Charles G. King (1896-), at the University of Pittsburgh, reported that hexuronic acid was identical to the vitamin C that he and his associates had isolated from oranges and lemons. Both of these reports were published in 1932. A short while later, vitamin C was synthesized by two men: Walter Norman Haworth (1883-1950), an English chemist who also determined its chemical structure, and Tadeus Reichstein, a Polish-Swiss endocrinologist, who completed the vitamin's synthesis in 1933.
Today, vitamin C is credited with such uses as an anti-stress drug and for prevention and treatment of the common cold. In 1996, however, studies done on the use of vitamin C for the common cold have been inconclusive at best. It appears that children may benefit from high doses of vitamin C during "cold season," but there may be no heightened immunity for adults. Further controlled studies are necessary before any conclusions are made regarding vitamin C's effectiveness against the common cold.
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