Lead is an example of a contaminant mineral, which are minerals that impair the body’s growth, work capacity, and general health. They enter the food supply by way of soil, water, and air pollutions. Lead is a serious environmental threat to young children, and reducing blood lead levels in children is a goal of the Healthy People initiative.
Chemically similar to nutrient minerals such as iron, calcium, and zinc (cations with two positive charges), lead displaces them from some of the metabolic sites they normally occupy so they are then unable to perform their roles. For example, lead competes with iron in heme, but it cannot carry oxygen. Similarly, lead competes with calcium in the brain, but it cannot signal messages from nerve cells. Excess lead in the blood also deranges the structure of red blood cell membranes, making them leaky and fragile. Lead interacts with white blood cells, too, impairing their ability to fight infection, and it binds to antibodies, thwarting their effort to resist disease. Eating nutrient-rich foods and preserving a clean environment are the best ways to prevent lead contamination.