Something (More) in the Water

Page 6 of 6

Comment by

David Peck, D.O.

Although I agree overall with Dr. Loge's fine commentary on the benefits and the medicinal value of the Sulfur Spring waters that were administered to Sacagawea during her severe illness near the Great Falls of the Missouri, I would like to express my position on this issue.

Any possible benefit derived by Sacagawea from the Sulfur Spring water certainly was not equivalent to any modern electrolytic oral rehydration fluids such as Pedialyte or Gatorade, or intravenous salt solutions. As I have pointed out elsewhere,1 there were "possible benefits" from the minerals contained in the water. I believe these effects were minimal at best. I wrote this statement to avoid laboring over some complex intestinal physiology, which I did not feel was appropriate for my book.

The absorption of water in the small intestine is absolutely dependent on absorption of minerals (electrolytes), in particular, sodium. The absorption of glucose (products of carbohydrate digestion) or amino acids (products of protein digestion) is also dependent on a sodium-driven electrochemical gradient between cells lining the small intestine and the food solution inside the intestine.

Absorption of potassium from the diet is passive and does not require any specific transport mechanism. If there is a more concentrated potassium concentration inside the intestinal food solution, there will be movement of this mineral from inside the intestine into the body's circulation.

There is also "nutrient-independent" transport of some electrolytes in the distal large intestine. In people suffering from some diarrheas, if they become severely salt-depleted, a hormone from the adrenal glands (aldosterone) can increase sodium (and chloride) absorption in the distal colon.2 This in turn can encourage more water absorption at these sites as well. In general, the large intestine is more able to reabsorb water into the body than the small intestine.

Electrolyte absorption in the intestines is, without question, best accomplished in the presence of amino acids and sugars in the diet, as Dr. Loge has noted. The mineral water administered to Sacagawea makes a more interesting story from the expedition than it did as an effective medicinal or rehydration solution. However, there may have been a slight beneficial effect.

Discussion pages, which can be introduced anywhere in Discovering Lewis & Clark®, are open to serious, thoughtful, literate comments, corrections, and counter-views.

1. David Peck, D.O., Or Perish in the Attempt: Wilderness Medicine on the Lewis and Clark Expedition (Helena, Montana: Farcountry Press, 2002), p. 161.

2. A deficiency of aldosterone hormone from the adrenal glands results in Addison's disease, with which President Kennedy was afflicted.

Funded in part by a grant from the Montana Committee for the Humanities