Putative Therapeutic Roles for Zinc

Evidence supporting zinc as an important antioxidant for skin

Antioxidants play a critical role in keeping skin healthy. The antioxidant benefits of vitamin C and E are well known, but the importance of the trace mineral, zinc, has been overlooked. This article reviews the evidence supporting zinc's antioxidant role in protecting against free radical-induced oxidative damage. Zinc protects against UV radiation, enhances wound healing, contributes to immune and neuropsychiatric functions, and decreases the relative risk of cancer and cardiovascular disease. All body tissues contain zinc; in skin, it is five to six times more concentrated in the epidermis than the dermis. Zinc is required for the normal growth, development and function of mammals. It is an essential element of more than 200 metalloenzymes, including the antioxidant enzyme, superoxide dismutase, and affects their conformity, stability, and activity. Zinc also is important for the proper functioning of the immune system, and for glandular, reproductive and cell health. Abundant evidence demonstrates the antioxidant role of zinc. Topical zinc, in the form of divalent zinc ions, has been reported to provide antioxidant photoprotection for skin. Two antioxidant mechanisms have been proposed for zinc: zinc ions may replace redox active molecules, such as iron and copper, at critical sites in cell membranes and proteins; alternatively, zinc ions may induce the synthesis of metallothionein, sulfhydryl-rich proteins that protect against free radicals. No matter how they work, topical zinc ions may provide an important and helpful antioxidant defense for skin.

Parenteral supplementation with zinc in surgical patients corrects postoperative serum-zinc drop

Zinc has been known for a long time to facilitate wound healing. But, so far, supplementation trials in patients treated by major severity surgery gave either partial or controversial results. In a double-blind, randomized study including 30 patients, we show that zinc supplements (30 mg/d for 3 d) administered by a drip correct postoperative drop of serum zinc, that this correction concerns the available part of serum zinc (i.e., zinc that is bound to compounds other than alpha-2 macroglobulin in serum), and that this supplementation can improve clinical wound healing. Possible influence of increased urinary output after the intervention is discussed, and we found that serum cortisol remains stable when zinc/albumin ratio is stable, and increases sharply when the same ratio drops. Cortisol, therefore, seems to play a major role in zinc redistribution after surgery.