EFFECTS OF MICRONUTRIENTS ON METAL TOXICITY

There is growing evidence that micronutrient intake has a significant effect on the toxicity and carcinogenesis caused by various chemicals. This paper examines the effect of micronutrient status on the toxicit y of four nonessential metals: cadmium, lead, mercury, and arsenic. Un fortunately, few studies have directly examined the effect of dietary deficiency or supplementation on metal toxicity. More commonly, the ef fect of dietary alteration must be deduced from the results of mechani stic studies. We have chosen to separate the effect of micronutrients on toxic metals into three classes: interaction between essential micr onutrients and toxic metals during uptake, binding, and excretion; inf luence of micronutrients on the metabolism of toxic metals, and effect of micronutrients on secondary toxic effects of metals. Based on data from mechanistic studies, the ability of micronutrients to modulate t he toxicity of metals is indisputable. Micronutrients interact with to xic metals at several points in the body: absorption and excretion of toxic metals, transport of metals in the body; binding to target prote ins; metabolism and sequestration of toxic metals, and finally, in sec ondary mechanisms of toxicity such as oxidative stress. Therefore, peo ple eating a diet deficient in micronutrients will be predisposed to t oxicity from nonessential metals.