Final answer:
In 1747, James Lind conducted an experiment which led to the discovery that citrus fruits could prevent and cure scurvy among sailors. The treatment involved supplementing the sailors' diet with lemons and limes, and this method was later adopted by the British Royal Navy, earning sailors the nickname 'limeys'. Lind's experiment is considered a foundational clinical trial in medical history.
Step-by-step explanation:
The first treatment for scurvy in 1740 can be credited to the landmark work of the Scottish surgeon James Lind. Through a methodical experiment on a British ship, Lind sought a cure for scurvy, a disease characterized by symptoms such as bleeding gums, tooth loss, and delayed wound healing. In 1747, Lind began his scurvy experiment by selecting 12 sailors who showed signs of the disease and dividing them into six pairs. All received the same diet, with each pair given a different daily dietary supplement.
Lind's study emphasized the importance of keeping the diet consistent among all participants, adding only the variable of the daily supplement to accurately observe the effects. Although factors other than diet, such as environment or health conditions, could have affected the outcome, the standardized diet helped to minimize confounding variables. The sailors receiving citrus fruits showed marked improvement, with those given lemons and limes achieving full recovery or significant health gains within just five days, despite the trial's abrupt end due to the depletion of citrus fruits.
The sailors who received cider as their supplement also exhibited some improvement in scurvy symptoms, possibly due to cider's limited vitamin C content. Lind's identification of the daily supplement as the independent variable and the improvement of scurvy symptoms as the dependent variable provided robust evidence that citrus fruits could cure scurvy. This discovery had a profound effect: the adoption of citrus fruit, particularly lemons and limes, into the British Royal Navy's diet saved countless lives. The term 'limey' eventually became a nickname for British sailors.
Nevertheless, the true underlying cause of scurvy, a vitamin C deficiency, remained unknown until almost two centuries later. Today, access to foods rich in vitamin C, such as citrus fruits, tomatoes, and peppers, makes scurvy rare. Recognizing the role of vitamin C in preventing scurvy, the British navy later mandated that ships carry lime juice to ensure sailors received their daily ration. James Lind's contributions to the understanding and treatment of scurvy represent a significant milestone in medical history, pioneering clinical experimentation that would set a precedent for future scientific breakthroughs.