Sometimes when we stroll the beaches we find the little plant called scurvy grass. It is not a grass; it belongs to the mustard family (common names can be very misleading). In the course of history, this name may have been applied to other plants, perhaps especially other members of the mustard family, and so the historical records need to be considered with care.
Finding this plant on a beach walk this summer prompted an interest in learning more about the plant and the ailment called scurvy, revitalizing some bits of information once known but long forgotten (a burgeoning category these days, alas!) and adding enough other bits to make a more or less coherent story.
Scurvy is caused by a deficiency of vitamin C (ascorbic acid). Humans, as well as most other primates (monkeys and apes), and some other mammal species do not make their own vitamin C, so they have to get it from their food. Why it happened that we (and the others) lost this ability, given that most mammals do synthesize their own vitamin C, is still unexplained, although several ideas have been proposed.
Vitamin C is need for making collagen, a protein that is an essential component of skin, tendons, ligaments, and many other body parts. Without it, various really ugly symptoms develop and death follows, unless the disease is treated with dietary vitamin C. Scurvy was a serious problem for sailors on the high seas, for armies in the field, for the Crusaders and some Antarctic explorers, for the early colonists in North America, and in general for people with limited diets. Historically, the death rates from scurvy were sometimes extremely high; for example, when Vasco de Gama rounded Cape Horn in 1497, over half of his crew of one hundred and sixty sailors had died.
When Bering’s expedition was stranded in the Commander Islands in the winter of 1741-42, scurvy –already a problem on board ship—became even more serious, killing off a number of men. Georg Steller, the ship’s doctor and naturalist for the expedition, tried to persuade the officers that eating greens would help, but his pleas met with only reluctant and limited acceptance, even in the face of evidence that suitable treatment of scurvy-sick men restored them to health. Steller also knew that eating fresh meat (raw or only slightly cooked) from animals that can make vitamin C would help. In this knowledge, Steller was well ahead of the Scottish naval doctor, James Lind, who published the first medical paper about the treatment of scurvy. Even after Lind’s paper, it was decades before preventative measures became standard aboard ship; Captain Cook in the 1770s was ahead of most other sea captains and successfully avoided a scurvy epidemic.
In fact, there is a long history of knowledge about the successful treatment and prevention of scurvy. Well before Steller’s day, an English captain on the way to the East Indies in 1601 successfully treated scurvy on board his ship, with the sailors on other ships of the squadron died in droves. An outbreak of scurvy on Cartier’s exploratory expedition to Newfoundland in 1536 or so was successfully treated by an infusion of conifer needles (variously reported as spruce or arbor vitae); this treatment was suggested by local Natives. Still earlier, the Vikings on the way to Greenland are said to have made use of scurvy grass or a similar species. And long before that, in the fifth century, the Chinese may have known how to treat the disease. Indeed, over two thousand years ago, doctors in the middle-eastern region wrote about treating scurvy. Despite the accumulated wisdom and concrete evidence, scurvy prevention aboard ship did not become customary until the early 1800s. It was not lack of knowledge that prevented regular use of dietary sources of vitamin C!
How good is scurvy grass as a source of vitamin C, compared to other foods? Judging from published data on the vitamin C content of various raw plant materials, scurvy grass is not particularly rich in this vitamin. In fact, the leaves of many other species contain far more vitamin C than scurvy grass. For example, the leaves of apple, birch, willow, and certain primroses contain levels of vitamin C many times higher than that of scurvy grass; primroses actually have had some medical uses, but humans don’t usually eat apple or birch or willow leaves. Rose hips are reported to be top-notch sources. Citrus juices are commonly used sources for humans but, like scurvy grass, they are not especially high in vitamin C. However, a high intake of plant material with moderate amounts of the vitamin would provide an adequate supply—quantity compensating for quality.
Meat –raw or only lightly cooked—can be a surprisingly decent source of vitamin C; internal organs tend to provide more than muscles. A study of the diet of Arctic Inuit people revealed that the liver of ringed seal and muktuk from beluga whales (especially the outermost skin) would be good dietary sources, when at least two hundred grams (about seven ounces) were eaten every day. The content in these animal sources was similar to that in licorice root and sorrel leaves, but I’d guess that the Inuit were far more likely to eat that much meat than the equivalent amount of leaves.
The vitamin C content of most foods is decreased by exposure to heat (tomatoes and seal livers seem to be exceptions). Cartier’s infusion of conifer needles would have had a very low concentration of the vitamin if it was prepared in hot water, yet it appeared to work. Considerable loss of the vitamin from plants occurs when the plant material is stored even for a few days, but the loss varies with temperature and other conditions. In general, the bottom line for most foods is “eat it raw!” Muktuk, anyone?