Metals and Disease

Metals are a part of our daily life. They are used for construction and for countless products (e.g., cars, mobile phones, or computers). Without the use of metals, human society would have not been developed to its current stage. While the raw materials are provided by our planet, humans learned to extract metals from mineral ore and to refine them. As a consequence to their wide use in the modern world, we are all exposed to metals and metal compounds to a degree that was rare before the industrial age. Exposing the cell(s) of living organisms to elements which were hardly available during genesis of life causes multiple effects on those cells and ultimately human health will be affected. Some metals serve critical functions in the human body. Iron is a necessary component of hemoglobin in red blood cells. Copper, manganese, zinc, cobalt, chromium, molyb-denum, and selenium are all required as enzyme cofactors or prosthetic groups, and human disease results if the diet is deficient in the metals. However, exposure of humans to excessive levels of " physiologic " metals are associated with disease. Other metals, such as lead, aluminum, and arsenic, have no known beneficial effects in the human body and have only toxic actions. (This issue does not describe the positive health effects of some essential metals which are crucial to maintain normal body function.) This special issue presents the latest scientific insights into how metals influence and change cell and body function. One of the contributions of this special issue gives " a global primary health care perspective " linking the risks of metal exposure of humans to the contamination of the environment. The authors highlight the concern that primary care workers possibly underestimate occupational and environmental exposures to chemicals in clinical evaluations. The paper summarizes worldwide studies which explore the relationship between metal exposures and adverse health effects. Finally it suggests some guidelines to evaluate basic occupational and environmental exposure. Other two papers emphasize health effects of metals on the cardiovascular and the nervous system. Clearly both systems have a major impact on human health. The papers demonstrate that the functions of both systems are clearly impaired by metals. The paper on the cardiovascular system proposes a mechanism of action for interactions between genetic, nutritional, and environmental factors, while the paper on the nervous system emphasizes the multiple sites of action of a single metal at …