Effect of time exposure to high altitude on zinc and copper concentrationsin human plasma

Background: Research has focused mainly on the relationship of zinc and cop per contents and physical stresses like running, cycling, etc. It has also been reported that other forms of stresses change the concentration of thes e trace elements in humans. However,there are no reports on the effects of high altitude induced hypoxic stress on the plasma levels of these metals. Since hypoxia is one of the important stresses, we considered it appropriat e to observe the changes in the levels of zinc and copper concentrations an d in certain related zinc and copper enzymes and hormones in the plasma of human volunteers on acute induction to high altitude. From these findings, we intended to ascertain whether supplementation of these trace elements wo uld be required for optimal health under such conditions. Hypothesis: On ac ute induction to hypoxia, contents of these trace elements may change as th e requirements of stressed organs and tissue may increase. Hence, further s upplementation may be beneficial under hypoxic stress for better adaptabili ty. Method: Volunteers were divided into two groups: with and without zinc and copper salt supplementation. Blood samples were collected at sea level and on induction to acute hypoxia on days 3 and 10. Trace mineral contents and their related enzyme (alkaline phosphatase) and hormone (ceruloplasmin) levels were determined in plasma samples. Results:Plasma zinc contents wer e significantly reduced upon induction to high altitude in the non-suppleme nted group, but not in the zinc-supplemented group. Alkaline phosphatase ac tivity increased significantly upon induction to the high altitude stress. The enzyme activity remained elevated up to day 10 of the stress. Plasma co pper contents and ceruloplasmin activity did not change upon induction to h igh altitude. Conclusion: Under hypoxic stress, circulating levels of zinc and alkaline phosphatase in plasma changed appreciably as plasma zinc was t ransported into the organs and tissues. However, circulating levels of copp er and ceruloplasmin in plasma did not change, indicating no extra suppleme ntation of copper is required under hypoxic stress.