In the mid-18th century, the British Royal Navy was the most powerful maritime force in the world, but its dominance came at a high cost. Among the greatest threats to sailors was not enemy cannon fire or storms at sea, but scurvy—a devastating disease marked by weakness, swollen gums, joint pain, and eventual death. Between the 16th and 18th centuries, scurvy is estimated to have killed more British sailors than all naval battles combined.
Scurvy arises from a deficiency of vitamin C, or ascorbic acid, which is essential for collagen synthesis, iron absorption, and immune function. Symptoms of scurvy have been recorded in Ancient Egypt as early as 1550 BC, and in Ancient Greece, during the time of physician Hippocrates. Although scurvy was not understood at that time, the knowledge that certain foods could prevent or cure the disease was recognized long before vitamins were identified.
“James Lind: Conqueror of Scurvy” by Robert Thom, circa 1952. Credit: Wikimedia Commons
When Vasco da Gama sailed to India in 1497, he observed that including citrus fruits in the diets of sailors seemed to keep the symptoms of scurvy at bay. In response, the Portuguese began planting fruit trees and vegetables on the island of Saint Helena, a key resupply stop for homeward-bound ships from Asia. Sick sailors, especially those suffering from scurvy, were sometimes left there to recover and be picked up by later vessels if they regained their health.
In 1536, while navigating the St. Lawrence River, French explorer Jacques Cartier faced a severe outbreak of scurvy among his crew. Local Indigenous people provided a remedy—a tea made from the boiled needles of the aneda tree (likely a type of cedar or pine), which proved effective in restoring the health of his men. By the time Spanish friar and physician Agustin Farfán published a book recommending oranges and lemons as a cure for scurvy in the late 16th century, this remedy was already common knowledge in some parts of Europe.
Despite this knowledge, sailors continued to die in vast numbers at sea. It was apparent that the cure for scurvy had been found and then repeatedly forgotten, overlooked, or dismissed. This was partly because of lack of communication between travellers and those responsible for their health, and also because of the practical difficulties of storing fresh fruits and vegetables on long voyages without spoilage.
Historians estimate that during the Age of Exploration, scurvy claimed the lives of at least two million sailors. The scale of the devastation is reflected in the records of early expeditions: Vasco da Gama lost 116 of his 170-man crew in 1499, and in 1520, Ferdinand Magellan lost 208 of 230 men—mostly to scurvy. During Royal Navy officer George Anson’s circumnavigation between 1740 and 1744, nearly two-thirds of his crew—about 1,300 of 2,000 men—perished within the first ten months, again largely due to the disease.
The prevailing medical theory at that time was that scurvy was a digestive disorder caused by a poor diet, particularly the consumption of salted meat and preserved food over long periods. The harsh maritime environment—cold, damp, and crowded—was also blamed. Others suggested that the absence of certain traditional staples, such as beer or fermented vegetables, contributed to the illness. A handwritten household book authored by a Cornishwoman in 1707 contained various medicinal and herbal recipes as a cure for scurvy. The recipe consisted of extracts from various plants mixed with a plentiful supply of orange juice, white wine, or beer.
It was not until 1747 when Scottish naval surgeon James Lind formally demonstrated that scurvy could be treated by supplementing the diet with citrus fruit, in one of the first controlled clinical experiments reported in the history of medicine.
James Lind
James Lind (1716–1794) was trained in Edinburgh and joined the Royal Navy as a surgeon’s mate in 1739. Over years of service, he observed the high mortality rates from scurvy during long voyages and became determined to find an effective cure.
Lind thought that scurvy was due to putrefaction of the body that could be helped by acids, so he included an acidic dietary supplement in the experiment. While serving aboard HMS Salisbury in 1747, Lind selected 12 sailors suffering from similar cases of scurvy and divided them into six groups of two. All were housed in the same conditions and received the same basic diet, but each group was given a different supplement:
- A quart of cider daily
- Twenty-five drops of elixir of vitriol (diluted sulfuric acid) three times a day
- Two spoonfuls of vinegar three times a day
- Half a pint of seawater daily
- A mixture of garlic, mustard seed, radish root, and other spices
- Two oranges and one lemon daily
The differences in outcome were dramatic. The pair who received citrus fruit recovered quickly—one was fit for duty in just six days, and the other showed significant improvement. None of the other treatments had any measurable benefit.
Though the experiment was small and not randomized by modern standards, Lind’s trial marked a critical departure from anecdotal treatments. He had established a control group, treated all subjects in a uniform environment, and directly compared outcomes—elements that are fundamental to clinical trials today.
Although the results of his experiment were clear, Lind did not clearly declare in his 1753 Treatise on the Scurvy that citrus juice was the definitive cure. Instead, he gave equal or greater attention to other potential remedies, including an infusion of malt, which he personally endorsed as a treatment. Lind’s reluctance to fully embrace the implications of his own ground-breaking clinical trial can be attributed, in part, to the limited scientific understanding of the time and the deeply entrenched medical theories that shaped his thinking.
While innovative for its methodological approach, Lind’s treatise was lengthy, inconsistent, and at times contradictory. It remained anchored in the prevailing medical orthodoxy, particularly humoral theory, which interpreted disease as a result of imbalances or corruptions within the body. Like many of his contemporaries, Lind believed scurvy was caused by a combination of factors such as poorly digested or putrefying food, stagnant or contaminated water, excessive physical exertion, and prolonged exposure to damp, cold conditions that inhibited healthy perspiration.
As a result, although Lind acknowledged the benefits of citrus fruit, he did not champion it as a singular cure. Instead, he viewed scurvy as a complex disorder requiring a multifaceted approach to treatment. His cautious interpretation, combined with the treatise’s dense and sometimes ambiguous prose, delayed the widespread adoption of citrus as a standardized preventive measure in naval medicine for several more decades.
Similarly inaccurate theories on scurvy were promoted by Sir John Pringle, Surgeon General of the British Army and later President of the Royal Society, who proposed that scurvy was caused by a deficiency of “fixed air” (what we now know as carbon dioxide) in the tissues, and that this could be prevented by drinking infusions of malt and wort. These ideas were taken seriously when James Cook set sail on his first circumnavigation in 1768. He brought with him supplies of malt and wort, as well as beer and sauerkraut—though notably, he did not include lemons or other citrus fruits. Fortunately, sauerkraut is a fermented food rich in vitamin C, and its inclusion in the crew’s diet proved effective. Cook did not lose a single man to scurvy during the voyage, a rare achievement in that era.
Within the Royal Navy, however, practical experience had gradually convinced many officers and naval surgeons that citrus juices were the most effective remedy for scurvy. This growing conviction culminated in a pivotal moment in 1794, when Rear Admiral Alan Gardner insisted that lemon juice be issued aboard HMS Suffolk for a twenty-three-week, non-stop voyage to India. In a significant departure from previous practice, the usual rations of malt, wort, and elixir of vitriol were replaced with citrus juice.
When the Suffolk arrived in India in March 1795, after a voyage of nearly four months, not a single case of scurvy had been recorded. In fact, the crew was reportedly in better health upon arrival than when they had departed. The success was so striking that it prompted immediate action. Later that same year, the British Admiralty officially adopted lemon juice as a standard dietary supplement across the Navy. While it took several more years to establish the supply chains and infrastructure needed to provision the entire fleet with adequate quantities of citrus, the decision marked a turning point.
James Lind’s clinical trial is considered a foundational moment in evidence-based medicine. Though crude by modern standards, his approach was methodical and empirical. It represented one of the earliest documented efforts to test medical treatments in a controlled and comparative fashion. Lind's legacy is now honoured through institutions such as the James Lind Library, which promotes the history and understanding of fair tests of treatments. His trial is often cited in medical training as the origin of the clinical method.
References:
# James Lind. A Treatise of the Scurvy.
# Kenneth J Carpenter. The History of Scurvy and Vitamin C.
# M. Bartholomew. "James Lind's Treatise of the Scurvy (1753)." Journal of the Royal Society of Medicine
# Iain Milne, Who was James Lind, and what exactly did he achieve, Journal of the Royal Society of Medicine
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