Scurvy and the Foundations of the Science of Nutrition

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Scurvy and the Foundations of the Science of Nutrition

Overview

Scurvy, a serious nutritional disorder caused by a lack of vitamin C, became a significant problem aboard ships during the early modern era. The disease often killed sailors on lengthy voyages, and was so pervasive that ships frequently set sail with a double crew simply to have enough men to finish the voyage. In the mid-eighteenth century, a shipboard experiment by Scottish physician James Lind showed the value of citrus juice in preventing scurvy.

Background

Unlike most animals, humans cannot manufacture vitamin C and must eat a sufficient amount to stay healthy. Without enough vitamin C collagen begins to break down, causing a loss of bone, cartilage, and dentin—the calcerous material that makes up teeth. The early symptoms of scurvy, which begin to develop after about 12 weeks of poor diet, include lethargy and dry skin; more serious problems emerge after six to seven months, including an inability to heal wounds, painful swollen joints, and the characteristic soft, bleeding gums and loose teeth.

Although descriptions of disease that resemble scurvy can be found in ancient writings, the first reliable accounts are medieval cases that were documented during the Crusades. Despite being recognized, the syndrome had no name until the early modern era, when long voyages of exploration caused extensive dietary insufficiencies. Vasco da Gama's landmark voyage of 1497-1499, in which he successfully sailed to India by first going south around the Cape of Good Hope in Africa, was plagued by scurvy, which killed 100 out of the original 170 crewmen during the voyage. On both the outgoing and return legs of this journey, many "suffered from their gums; their legs also swelled, and other parts of the body and these swellings spread until the sufferer died, without exhibiting symptoms of any other disease." In the years that followed, scurvy became a ubiquitous problem on long journeys for trade and exploration, often taking many lives.

Magellan's trans-Pacific voyage of 1519 set sail from Spain with five ships and 260 men. During the 3-year voyage their supplies ran out, causing rampant scurvy and horrendous hunger. A crewman's journal noted, "We ate only old biscuit reduced to powder, and full of grubs, and stinking from the dirt which the rats had made on it when eating the good biscuit, and we drank water that was yellow and stinking. The men were so hungry that if any of them caught a rat, he could sell it for a high price to someone who would eat it." Only 18 of the men returned to Spain in 1522.

Shipboard diets were notoriously poor, especially for the crew. Sailors had to rely on provisions that were easily stored in quantity and were as nonperishable as possible. In this era, such requirements meant a great deal of salted meat and hard biscuit. Fresh provisions were available only at landfalls, which often helped cure cases of scurvy and other health problems, but not always. Sailors were also prone to a number of other illnesses, including typhus and tuberculosis, so that they often suffered symptoms of scurvy along with other ailments.

Although scurvy was recognized as a illness, its causes were unknown. Some captains and ships surgeons, however, did make the connection between diet and health. Around the beginning of the seventeenth century two men, Sir Richard Hawkins and Captain Lancaster of the East India Company, recognized the value of lemon juice in preventing scurvy. Another East India Company physician published a book called Surgeon's Mate in which he encouraged its use as a cure for scurvy as well. But these treatments were by no means universally adopted. Because sailors endured filthy, poorly ventilated quarters, in addition to a limited diet, scurvy was often attributed to their appalling accommodations and simply accepted as a hazard of marine life. Since many sailors were convicts, criminals, or lowlifes plucked from the depths of society, their quarters were given minimal consideration.

James Lind is credited with proving the efficacy of citrus over other dietary treatments. In 1747 Lind, a British naval surgeon, conducted a shipboard experiment. Taking 12 sick sailors, each of whom showed similar symptoms of scurvy, Lind treated them with six different remedies common at that time. Keeping all other factors the same, Lind gave the men daily doses of either cider, vinegar, sea water, oranges and lemons, elixir vitriol (sulfuric acid), or an "electuary" (paste) made up of various herbs. He found that those men given the oranges and lemons most quickly improved, despite the fact that the supply of these fruits ran out after only six days. Second to begin recovery were those men given hard cider, which is known today to retain some vitamin C. Lind eventually followed up his experiment by publishing A Treatise of the Scurvy (1753), a definitive study of the disease and its remedy.

Impact

Lind's experiment is generally credited as the first clinical trial. Although he did not have an untreated "control" group by which to measure success, he nonetheless compared results achieved to the various remedies tried. Unfortunately, his findings did not result in the immediate adoption of his treatment of scurvy. More than 40 years would pass before the British Admiralty mandated a daily ration of lemon juice for each sailor.

The humoral theory of health, which had been developed by the ancient Greeks and was dominant in Europe through the eighteenth century, held that disease was caused by an imbalance in the body's four humors: blood, phlegm, black bile, and yellow bile. Diet had long been used by ancient physicians in treating illness, as it was believed that the humoral balance was directly affected by diet. (There was, however, no concept of disease caused by a lack of food.) Humors were also affected by environment, climate, and host of other individual variables. Medical theory of the time, therefore, attributed scurvy to both diet and the conditions in which sailors existed.

The most respected medical figure of the early eighteenth century, Herman Boerhaave (1668-1738), argued from theory (rather than experience) that sailors' salt-rich diets produced a corruption in their blood. This corruption could be counteracted by any of several acidic remedies. Lind himself believed that scurvy resulted from blocked pores in the skin, which prevented the body from eliminating dangerous vapors and humors through the skin. He thought that a cold, damp climate and the close "corrupted" air on board ships created this problem. Thus, the usefulness of citrus fruits, and particularly of the "rob" (a concentrated syrup that allowed lemon and other citrus juice to be preserved) was in their ability to counteract these environmental conditions by cleansing the body. Lind's treatise also recommended fresh air, exercise, and cleanliness as necessary for health. Although the treatment was effective, these theories on scurvy's causes pointed many away from the value of foods rich in vitamin C, and, in some cases, away from diet entirely.

A successful demonstration of the use of fresh provisions came with the explorations of Captain James Cook (1728-1779) from 1776-1780, during which the only death was a result of tuberculosis. Cook, who seems to have been well aware of Lind's treatise, is noted to have insisted on continually acquiring fresh provisions for his crew at each landfall. Again, however, the recognition of the importance of diet was tempered by an additional insistence on cleanliness, fresh air, and sufficient rest for the men, all of which were believed to be contributing factors to scurvy.

The use of citrus was not put into widespread effect until the end of the eighteenth century. Gilbert Blane (1749-1834), another Scottish physician trained in Edinburgh, was appointed as physician of the British fleet in 1781. Blane was also familiar with Lind's work and supported his findings. He immediately began to recommend rations of citrus for the fleet to prevent cases of scurvy. Other officials, however, held differing views on what was most useful for treating scurvy, and Blane's suggestions were disregarded. Finally, in 1796, after being appointed a commissioner to the Board of the Sick and Wounded Sailors, Blane convinced the Lord of the Admiralty to order that all ships be rationed sufficient quantities of lemon juice to give each sailor three-quarters of an ounce (20 ml) per day. This effort produced a dramatic drop in cases of scurvy and led to a new nickname for British sailors. As "lime" was a common term for both lemons and limes, they became known as "limeys."

While rations of lemon juice helped eliminate scurvy in the British naval fleet, it remained a constant problem for other nations' sailors. Scurvy has also been a problem anywhere that diet has been limited, including in the early New World colonies, in jails, and during sieges or other military campaigns. More recent scurvy outbreaks include the Potato Famine in Ireland (potatoes are rich in vitamin C) and the California Gold Rush of 1849. An epidemic of infantile scurvy occurred in Europe and North America in the late nineteenth century as well-to-do women increasingly switched from breast-feeding to using preserved milk, which did not contain any vitamin C. The current understanding of scurvy came only in the twentieth century. Not until after World War I was scurvy widely accepted as a deficiency disease and vitamin C isolated and identified as the causative factor.

KRISTY WILSON BOWERS