Scurvy

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Scurvy (N.Lat. scorbutus) is a deficiency disease that results from lack of vitamin C, which is required for correct collagen synthesis in humans. The scientific name of vitamin C, ascorbic acid, is derived from the latin name of scurvy, scorbutus. Scurvy leads to the formation of liver spots on the skin, spongy gums, and bleeding from all mucous membranes. The spots are most abundant on the thighs and legs, and a person with the ailment looks pale, feels depressed, and is partially immobilized.

Scurvy was at one time common among sailors and others who were on ships, whose ships were out to sea longer than perishable fruits and vegetables could be stored and by soldiers who were similarly separated from these foods for extended periods. It was described by Hippocrates (c. 460 BC–c. 380 BC). Its cause and cure has been known in many native cultures since prehistory. For example, in 1536, the French explorer Jacques Cartier, exploring the St. Lawrence River, used the local natives' knowledge to save his men who were dying of scurvy. He boiled the needles of the arbor vitae tree (Eastern White Cedar) to make a tea that was later shown to contain 50 mg of vitamin C per 100 grams.

However it was a Scottish captain in the British Royal Navy, James Lind ( 1716 – 1794) who first proved it could be treated with citrus fruit in experiments he described in his 1753 book, A Treatise of the Scurvy.

In infants, scurvy is sometimes referred to as Barlow's Disease, named after Sir Thomas Barlow ( 1845- 1945), a British physician who described it. Barlow's disease is different from Barlow's syndrome.

Scurvy is also known as Moeller's disease and Cheadle's disease.

Prognosis

Untreated scurvy is always fatal. However, since all that is required for a full recovery is the resumption of normal vitamin C intake, death from scurvy is rare in modern times.

Pathophysiology

Normal collagen synthesis depends upon the hydroxylation of proline and lysine residues in the endoplasmic reticulum, to form hydroxyproline and hydroxylysine, respectively. Prolyl and lysyl hydroxylase, the enzymes that catalyze the hydroxylation reactions, require vitamin C as a cofactor. In cases of chronic deficiency, hydroxyproline and hydroxylysine are not formed in appreciable amounts and the resulting collagen fibrils are considerably weaker. This is due in part to the loss of hydrogen bonding between hydroxyprolines and constituent heteroatoms within the collagen α-helical trimer, which otherwise confer mechanical stability.

History

Scurvy was probably first observed as a disease by Hippocrates. In the 13th century the Crusaders suffered from scurvy frequently, and it has inflicted terrible losses on both besieged and besieger in times of war. Scurvy was one of the limiting factors of marine travel, often killing large numbers of the passengers and crew on long-distance voyages. It even played a significant role in World War I.

The British civilian medical profession of 1614 knew that it was the acidic principle of citrus fruit which was lacking, although they considered any acid as acceptable when ascorbic acid (Vitamin C) was unavailable. In 1614 John Woodall (Surgeon General of the East India Company) published his book "The Surgion's Mate" as a handbook for apprentice surgeons aboard the company's ships. In it he described scurvy as resulting from a dietary deficiency. His recommendation for its cure was fresh food or, if not available, oranges, lemons, limes and tamarinds, or as a last resort, Oil of Vitriol (sulfuric acid).

However, it was not until 1747 that the treatment and prevention of scurvy by supplementation of the diet with citrus fruit such as lemons and limes was introduced into the British Navy by James Lind. It was in conforming to this policy that Captain James Cook persuaded his men to eat foods such as citrus fruits and sauerkraut during their voyages of discovery in HM Bark Endeavour. This major innovation ensured that not a single man was lost to scurvy during Cook's first voyage, although two did suffer from the disease for a time. This was a remarkable and practically unheard-of achievement in 18th century long-distance sea-faring.

The plant known as " scurvy grass" acquired its name from the observation that it cured scurvy, but this was of no great help to those who spent months at sea. During sea voyages, it was discovered that sauerkraut was of use in preventing scurvy. In the Royal Navy's Arctic expeditions in the 19th century it was widely believed that scurvy was prevented by good hygiene on board ship, regular exercise, and maintaining the morale of the crew, rather than by a diet of fresh food, so that Navy expeditions continued to be plagued by scurvy even while fresh meat was well-known as a practical antiscorbutic among civilian whalers and explorers in the Arctic. At the time Robert Falcon Scott made his two expeditions to the Antarctic in the early 20th century, the prevailing medical theory was that scurvy was caused by "tainted" canned food. It was not until 1932 that the connection between vitamin C and scurvy was established.

The use of limes by the Royal Navy to prevent scurvy gave rise to the name "limey" for a British sailor, which has been since extended to all British in American slang. The name " kraut" for a German soldier in World War II may similarly be based on the fact that the German Navy kept sauerkraut as scurvy prevention after the Royal Navy changed to limes.

Modern incidence

Scurvy is mostly caused by the lack of Vitamin C. In modern western society, scurvy is rarely present in adults. However, vitamin C is destroyed by the process of pasteurization, so babies fed with ordinary bottled milk sometimes suffer from scurvy if they are not provided with adequate vitamin supplements. Virtually all commercially available baby formulas contain added vitamin C for this reason, however heat destroys vitamin C. Human breast milk contains sufficient vitamin C to prevent scurvy on its own.

Scurvy is one of the accompanying diseases of malnutrition (other such micronutrient deficiencies are beriberi or pellagra) and thus is still widespread in areas of the world depending on external food aid. (See also the report from the WHO referenced below.)

Prevention

Scurvy can be prevented by a diet that includes limes, oranges, and lemons, or the juices of these fruits. Other good sources of Vitamin C are fruits such as guava, papaya, or strawberries. It can also be found in some vegetables, such as bell peppers, tomatoes, broccoli, potatoes, cabbage, and spinach.