Monday, August 16, 2010

Non-Negligable Loss of Minerals & Trace Elements With Sweat in Healthy Boxers

Turkish scientists (Saraymen. 2010) analyzed the sweat of 21 male cross-country boxers and found only a minor loss of trace elements copper, zinc and iron. As my plot of the study results as percentages of the recommended daily allowances (RDA) shows, the loss in magnesium, as well as the chromium are much more pronounced:
Figure 1: Loss of minerals and trace elements in 1L of sweat expressed as percentages of the RDA
Other than magnesium which is one of the commonest dietary supplements and is consumed in more than adequate amounts by most physically active adults (Hickson. 1986, 1987, 1986; Worme. 1990), studies suggest that chromium intake is rather on the lower end of the range:
Recent analyses of self-selected diets in the United States indicate that nutritionally balanced diets contain variable amounts of chromium ranging from 1.2–1.4 ng Cr/MJ (5–6 µg/1000 kcal) (8) to 3.6 ng Cr/MJ (57) based on the foods consumed. Other reported daily intakes of chromium in diets include 29 µg in Finland, 56 µg in Canada, 25 µg in England, and 37 and 28 µg in the United States. (8). Data on the chromium intakes of physically active persons per se are not available. Nielsen proposed that because overt signs of chromium deficiency are not present at a chromium intake of 50 µg/d, this amount may be adequate to ensure good health in most individuals (8). (Lukaski. 2000)
In spite of that, an increase in exercise performance via chromium supplementation has not yet been established and chromium deficiency is something that is practically non-existent. Furthermore, most multi-vitamins/-minerals do contain more than adequate amounts of chromium to keep you at a healthy level. Excessive consumption of additional chromium should thus be avoided, because a) it has been linked to chromosome damage (Stearns. 1995) and b) its positive effect on insulin signaling and diabetes is debatable and by no means thoroughly investigated.