An avoidable dietary deficiency.
Scurvy is a medical condition caused by a deficiency of vitamin C (ascorbic acid) in the diet. It is almost exclusively a human issue, since plants produce ascorbic acid in varying quantity, as do most animals. Primates and bats are the two major animal groups that do not have the ability to synthesize ascorbic acid, due to the lack of the enzyme L-gulonolactone oxidase. Ascorbic acid is an important component in various biological processes, including the development and maintenance of connective tissues. Early signs of ascorbic acid deficiency or scurvy are malaise and lethargy. This is followed by shortness of breath and bone pain. Later, gum disease and poor wound healing become evident. A diet for fresh foods is sufficient to prevent scurvy. Persons deprived of fresh food, such as when on a long sea voyage (prior to development of modern refrigeration and food preservation techniques), have proven highly susceptible to scurvy. Sailors on early European long-distance sea voyages, starting in the late 1400’s, suffered severely from this condition. In 1734, the Dutch physician Johann Bachstrom published a book recommending a diet of fresh vegetables to prevent scurvy. He was largely ignored. In the 1740’s, Royal Navy Admiral Edward Vernon required that citrus juice be added to the daily ration of grog (watered-down rum) provided to sailors in his fleet. Limes were readily obtainable by the Royal Navy from British colonies in the Caribbean, thus becoming the favored source of the citrus juice. His sailors seldom suffered from scurvy and came to be known as “Limeys”, a term later used to describe all Royal Navy sailors. Ironically, limes contain significantly less ascorbic acid than do lemons. If one consumes a regular amount of lime-flavored grog, though, scurvy can be avoided. Strangely, though, the Royal Navy did not make the consumption of citrus juice mandatory and scurvy continued to be a problem. During the Seven Years War and even into the early years of the Napoleonic Wars, scurvy killed more sailors than did enemy action. The artificial synthesis of ascorbic acid and its inclusion in dietary supplements has largely eradicated scurvy for persons consuming diets lacking in fresh fruits and vegetables.