Guest post by Rowena Fletcher-Wood
Scurvy plagued early sailors, and although many treatments were tried and promoted, a simple cure was masked for centuries behind a series of mistakes and misunderstandings.
This story begins at sea, long into a voyage after the fresh food stock had long run out and the sailors were left with only grains, hardtack and cured meats to eat. The sailors would become desperate as scurvy began to set in. Sailors were lost to scurvy in vast numbers, with estimates as high as two million lives lost between 1500–1800 AD.
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Scurvy is an unpleasant disease in every way. Although symptoms take weeks or months to develop, they get very nasty. First you become lethargic, anaemic and pale, and all of your joints and muscles ache. You lose your appetite and begin to develop spots on your thighs and legs. Soon you become feverish, sick, and weak; gums soften and bleed, legs swell, old wounds reopen. Depression sets in. Eventually, scurvy takes hold completely: your teeth fall out and gums turn blue, you bleed beneath your skin and from the follicles of hairs. You suffer cardiac arrest and die.
Scurvy is caused by a deficiency in vitamin C (ascorbic acid), which is present in many foods – including tomatoes, sweet peppers, strawberries and spinach – but in particular citrus fruits. Several pathways in the body rely on vitamin C; it is vital for building collagen in tissues. We also use it for lipid metabolism, neurotransmission and strengthening bone and blood vessels. Although many species are capable of synthesising their own vitamin C, humans and a few other animals cannot – it is an essential nutrient that must come from our diet. But until 1927, we didn’t even know it existed.
The ancient Greek physician Hippocrates knew that fresh fruit, especially citrus, had an antiscorbutic effect – it could prevented and cure scurvy. In 1747, James Lind systematically proved that the addition of citrus fruit to the diet both treated and prevented the disease, in a candidate for the first ever clinical trial. But the medical establishment were not convinced, and continued to promote other approaches, including good hygiene, exercise, avoiding tinned meat and improving morale. Some of these approaches were successful, including prescribing the peppery herb scurvy-grass, which is related to horseradish. Unknown at the time, scurvy-grass leaves are rich in vitamin C.
A common belief was that the acidic principle treated scurvy: doctors believed any acid would do and that citric acid in fresh fruits was merely the best. Accidental destruction of ascorbic acid in treatments that would otherwise have been effective was common. Although vitamin C is present in milk, this was destroyed by the new process of pasteurisation, leaving bottle-fed babies susceptible to scurvy. James Lind himself was guilty too, bottling and selling lime juice that promptly oxidised and became useless.
When the 1867 Merchant Shipping Act insisted that all ships carry citrus fruits, fresh lemons were substituted for cheap, abundant West Indian limes which were more acidic but had only a quarter of lemons’ ascorbic acid content. These fruits were juiced, stored in air and piped through copper tubing, oxidising the vitamin C. Later tests in 1918 showed the juice to be almost useless, but at the time this was masked by simultaneous advances in diet and marine travel that reduced the prevalence of scurvy.
We owe the discovery of vitamin C to guinea pigs. Two Norwegian physicians, Axel Holst and Theodor Frølich, decided in 1907 to induce in guinea pigs a disease called beriberi, now known to be cause by a deficiency of vitamin B1. They used the same dietary restrictions they had used to induce the disease in pigeons, but the guinea pigs developed scurvy instead. Pigeons produce their own vitamin C, but like us, guinea pigs cannot. This was an exciting moment in medical history: the diseased guinea pigs were the first examples of non-human scurvy sufferers.
In 1932, the Hungarian biochemist Albert Szent-Györgyi posted a sample of hexuronic acid – which he had isolated in 1927 – to the University of Pittsburgh, asking them to test it on guinea pigs with scurvy. The results would gain him the Nobel prize for medicine five years later, and hexuronic acid was renamed ascorbic acid to celebrate its antiscorbutic effect.
Decades of nutritional experiments and almost–correct hypotheses had seen scurvy become increasingly rare, but it took almost 200 years – from Lind’s nutritional trials to Szent-Györgyi’s experiments – to identify the secret in citrus fruits.
