. "8. The Effect of Excercise and Heat on Vitamin Requirements." Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations. Washington, DC: The National Academies Press, 1993.
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Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations
hours. Because plasma volume was not corrected for, it is difficult to interpret these changes.
The effect of pantothenic acid supplementation on exercise performance is equivocal. Compared with the placebo group, highly trained endurance runners who ingested 2-g doses of pantothenic acid per day for 2 weeks showed decreased exercise blood lactate levels and decreased oxygen consumption during prolonged exercise at 75 percent (Litoff et al., 1985). In contrast, Nice et al. (1984), using a controlled double-blind study, examined the effect of pantothenic acid supplementation (1 g per day for 2 weeks) or a placebo on run time to exhaustion in 18 highly trained distance runners. No significant differences were found between groups in run time or any of the standard blood parameters that were assessed (that is, cortisol, glucose, creatine phosphokinase, electrolytes).
There are no data to suggest that the need for pantothenic acid would be increased by living and working in a hot environment. Pantothenic acid is not lost to a significant degree in sweat (Mitchell and Edman, 1951).
Vitamin B12 plays a role in the formation and function of red blood cells (Ellenbogen, 1984) and may also function in protein, fat, and carbohydrate metabolism (Van der Beek, 1985). The condition of pernicious anemia was first described in 1924, and in 1929 a factor in liver was found to act as an antipernicious factor. It was not until 1948 that vitamin B12 was isolated and used to treat pernicious anemia (Ellenbogen, 1984).
No information is available on vitamin B12 status in athletes. However, it should be noted that athletes who are complete vegetarians may acquire a vitamin B12 deficiency because vitamin B12 is found mainly in animal products. Red cell vitamin B12 levels can indicate vitamin B12 status; however, low levels may also indicate a folate deficiency (Herbert, 1990). Several other tests are available to discern the two deficiencies; these are detailed elsewhere (Herbert, 1990).
Existing evidence suggests that vitamin B12 supplementation has no effect on performance (Williams, 1976). Montoye et al. (1955), in a doubleblind study, placed 51 adolescent boys (ages 12 to 17) into either an experimental group that consumed 50 µg of vitamin B12 daily, a placebo group, or a control group. No significant difference was found after 7 weeks between the supplemented group or the placebo group in the time to run 0.5 mile or in the Harvard step-test score (Montoye et al., 1955). Tin-May-Than et al. (1978) studied performance capacity in 36 healthy male subjects before and after injection of 1 mg cyanocobalamin given 3 times a week for 6 weeks. They found no significant improvement in , grip strength, pull-ups, leg lifts, or standing broad jump performance.