Nutritional Needs in Cold and High-Altitude Environments: Applications for Military Personnel in Field Operations

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Intake and Status

Of the fat-soluble vitamins, vitamin A has caused the most problems for polar explorers. Shearman (1978) presented a graphic description of vitamin A toxicity experienced by members of the three-man, 1912–1913 Mawson Australian Antarctic expedition, in which two men died, with only Sir Douglas Mawson surviving. Early in the expedition, Lt. Ninnis and one of the sleds loaded with most of the food fell into a crevasse and disappeared. Over the next 23 days, Xavier Mertz and Mawson were forced to reduce their daily food intake from the normal 34 oz (971 g) to 14 oz (400 g), much of which was dog meat that became available as each dog died (Mawson, 1915). As Mawson reported in his journal, ''It was a happy relief when the liver appeared; even if little else could be said for its flavor, it was easily chewed and demolished" (Shearman, 1978 quoting Mawson, 1915, p. 284).

Over a 9-d period, Mertz's health rapidly deteriorated, culminating in his death, with intervening severe bouts of dysentery, fecal incontinence, depression, delirium, peeling skin, and loss of hair—all symptoms characteristic of acute vitamin A toxicity. Shearman (1978) estimated that as little as 100 g of husky dog liver could contain upwards of 1,000,000 international units (IU) (300,000 µg retinol equivalents [RE]) of vitamin A, which was sufficient to cause the toxic symptoms experienced by Mertz.

This was not the only polar expedition that was thwarted by hypervitaminosis A. Today, with knowledge of the potential vitamin A toxicity from consumption of dog, seal, polar bear, or reindeer liver (Shearman, 1978), polar explorers or workers are unlikely to repeat such experiences, but warnings must still be given to those planning to spend long periods of time under such environmental conditions.

Sundaresan and Therriault (1969) studied rats chronically exposed to air temperatures of 5°C (41°F) and observed that the total liver levels of retinol did not differ from rats maintained at 25°C (77°F). Rats kept at 5° or 25°C (41° or 77°F) were injected daily with one of six different levels of retinoic acid. Thirty-day survival was used as the marker for adequacy of retinoic acid. At 5°C (41°F), at least 100 µg retinoic acid daily was necessary for survival and growth, whereas only 5 µg retinoic acid was required daily for survival and growth at 25°C (77°F). From this, they concluded that cold-adapted rats required a 20-fold greater intake of vitamin A than did their room temperature-acclimatized counterparts. Lui and Roels (1980) reported that vitamin A deficiency did not affect energy production by the Krebs cycle, but glycogen synthesis from lactate and glycerol appeared to be slowed down. Thus, restoration of depleted energy stores may be impaired by a severe deficiency of this vitamin.

Draper (1976) reported that Norwegian and Finnish Lapps (a race of formerly nomadic people residing in Northern Scandinavia) consume upwards of 50,000 to 62,000 IU of vitamin A (15,000 to 18,600 µg RE) per day,

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