Thursday, December 8, 2011

Scurvy, Scourge of the Seas

Scurvy-grass is a perennial plant of the brassica family which has a high tolerance for growing in salty soil, and has leaves rich in vitamin C. Those leaves have a peppery taste, which might explain why horseradish and wasabi were once classified as part of the same family. A near-extinct species native to New Zealand, Lepidium oleraceum, is also known as Cook’s scurvy-grass, because he took it with him on long voyages to prevent scurvy.

Dying of scurvy was (is) an exceptionally horrid way to perish. Vitamin C is essential  for the production and maintenance of collagen, the glue that keeps the human body together. Without vitamin C, you basically fall apart, slowly and steadily. Your cells breaks down causing bruising and bleeding; scar tissue opens up resulting in suppurating wounds; gums recede and teeth fall out. These initial symptoms are followed by jaundice, fever, neuropathy and death.

Long before anyone understood what caused scurvy, people understood how dangerous it was. Millions of sailors were lost to this dread disease, a deficiency, we now know, of vitamin C. While they didn’t know what brought it on, they knew how to prevent and cure it with various edibles that appeared to work — citrus fruits, fresh meat, pine needle teas, some berries and plants such as cabbage, or scurvy-grass, all of which are rich in vitamin C.

In 1740, citrus juice was added to sailors’ daily ration of grog, rum diluted with water, because it seemed to be a good preventative. (The practice of supplying sailors with grog continued until 1970.) Navy grog was a wretched drink, designed to mask the stagnant drinking water aboard ship. It was flavored with an assortment of herbs and spices, much like scurvy-grass ale. In 1723, scurvy-grass ale was common enough to be included in this recipe book by John Nott. It remained a popular drink for hundreds of years. It’s easy to see why it worked — in addition to the scurvy-grass, it includes half a dozen oranges.

In 1747, British Navy surgeon James Lind conducted the first clinical trial and proved citrus fruit prevented scurvy. He published the results in 1753 in his Treatise Of The Scurvy, though no-one took him seriously.

It’s interesting then, to see how it all went so wrong in the 19th century for British explorers who succumbed again and again to what had become an embarrassing problem. The epidemiological case of scurvy is a cautionary tale about barking up the wrong trees.

If citrus fruits — especially limes — were so good at preventing scurvy (a cure popular enough to earn British sailors the nickname “limeys”), then why didn’t lime juice produced in the Caribbean work at all? Because the variety of limes grown there were in fact far less rich in vitamin C than their cousins, and this was diminished further by being exposed to air piped through copper tubing, as copper and air destroys vitamin C.

But to the British, this seemed like evidence that citrus fruit was not the answer after all.

If meat was good at preventing scurvy, then why wasn’t all meat equally as good? How come canned meat — typically used on long voyages — had no effect? Because time and cooking destroys vitamin C.

But to the British, this seemed like proof that the cans themselves were the problem, rather than what they contained. In keeping with the new germ theory of disease, it seemed plausible that bacteria in faulty cans — ptomaine poisoning — was to blame.

Once this idea took hold, the Brits were stubborn to let go, despite all kind of evidence to the contrary, especially when it came to the competition. Norway’s Roald Amundsen had plenty of experience with which foods appeared to keep scurvy at bay, even if he had no idea why, and included them to great effect throughout his long career.

All of which draws attention to the dangers of ignoring folk wisdom that had been passed down for hundreds of generations. Why Scott of the Antarctic, possibly the last explorer for whom scurvy was a real threat, ditched it in favor of “modern” science when so much was at stake — their very lives — is  serious flaw in his otherwise commendable record of scientific achievement. Sir Ernest Shackleton, whose first foray into the Antarctic was cut perilously short by scurvy (from which he recovered), relied in his later expeditions on a far more varied diet that seemed less to do with deliberately science-based nutrition than old-fashioned comfort food (and drink), along with fresh seal meat, a good source of vitamin C, as it turns out.

The Cook’s and Confectioner’s Dictionary, John Nott, 1723

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