Friday, November 17, 2006

Food and the Corps of Discovery

Since the food theme is working out so well on this, the week before our American holiday of Thanksgiving, it seems only natural that today's lecture for the history of medicine elective course was Nutritional Lessons from the Corps of Discovery: the Lewis & Clark Expedition across the continent. Dr. William Connor and his wife Sonja Connor presented data on the nutritional aspects of the expedition, data which had been gathered primarily by premedical student Rachel Van Dusen before her departure for George Washington Medical School this fall.

An analysis of the nutritional intake of the Corps has apparently never been undertaken before, and it's easy to see why (and to see why the data gathering was left to a premed student): ten of the eleven volumes of the journals kept by Lewis and Clark, as well as journals kept by four other members of the expedition, were meticulously combed, day by day, for information on what the group ate. A nutritional analysis was then performed, and estimates of exercise were compiled to determine energy expenditures for various legs of the journey.

Connor began by reminding the group of the medical training which Meriwether Lewis received under Benjamin Rush at the University of Pennsylvania. Dr. Connor had actually spent much time in the History of Medicine Room this past summer combing through our copies of some of Rush's works to determine what Lewis could have learned from Rush about nutrition and diet. Although Lind's experiments on scurvy had been conducted earlier, Rush seemed to have no knowledge of this work, and like his contemporaries, he had no knowledge of vitamins. Nutritional diseases such as pellagra, rickets, night blindness, survey, goiter, anemia, and gout were well described, but no remedies were known.

What did this mean for the Corps? Well, since it was a military expedition, they were provisioned as military men would normally have been, with the same provisions being carried by naval vessels. Primarly salt, lard, and carbohydrates, the provisions contained zero sources of vitamin C. In fact, the provisions only wound up providing the expedition with eleven percent of the calories they required on the journey. An additional 18 percent of calories came from the Indians they encountered along the way, while the vast majority--71 percent--came from hunting and gathering activities.

Of the three sources of food, only the diet provided by the Indians was well balanced. The Mandan-Hidatsa were agricultural tribes who provided them with corn, beans, and squash; the Shoshones were accomplished hunter-gatherers; the Nez Perce were masters in the preparation of camas bulbs; and the Tillamooks gave the expedition 300 pounds of whale blubber (an excellent source of vitamin C). The Corps as a whole consumed excessive amounts of protein, purine, sodium chloride, fat, and choloesterol (as Connor noted, it was in a sense an early Atkins diet!). As a result, Clark experienced a severe bout of what was probably gout, and the crew as a whole suffered greatly from diarrhea.

Even with the additional food provided beyond what the Corps had carried with them, they experienced caloric deficits (based on the Connors' analysis) of 2915 calories per day on the trip west over the Bitterroots and a deficit of 3222 calories, again per day, on the return trip. Clearly, without the food they received from the Indians, the expedition members would have starved to death.

Which brings us back to Thanksgiving. I hope you all have a good one, with plenty to be thankful for. I myself will be thankful for, among other things, an extended holiday. I'll be away from Historical Collections & Archives throughout next week, so check back on Monday November 27 for the next glimpse into the collections.... Enjoy!

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