Cutaneous mineral loss in preadolescent girls

The excretion of Ca, Cu, Fe, Mg, Mn, Na, K and Zn in the sweat of 7-10 year old girls living in southwest Virginia was investigated. Sweat samples were collected in an arm bag which covered the hand and forearm of the subject. The samples were wet ashed and assayed on an Atomic Absorption spectrophotometer.

No significant correlation was found between mineral intake and excretion in the forearm sweat. There was no apparent relationship between the environmental temperature and the excretion of minerals in the sweat. There were great variations in mineral excretion among subjects. Calcium excretion ranged from 3.39-35.32 mcg/hr. Copper and magnesium excretion in the forearm sweat ranged from 0.04-0.66 mcg/hr and 0.00-7.98 mcg/hr, respectively. The range of excretion for the other minerals studied was: 0.005-0.074 mcg/hr of Mn; 9.78-62.51 mcg/hr of K; 9.95-57.9 mcg/hr of Na; 0.014-0.529 mcg/hr of Fe; and 0.10-3.71 mcg/hr of Zn. Reasons for discrepancies between these results and those reported in the literature are discussed. Suggestions for further research on the cutaneous mineral excretion of the preadolescent age group are recommended.