What Are Heavy Metals?

A peer-reviewed review by Tchounwou and colleagues defines heavy metals as naturally occurring elements that have a high atomic weight and a density at least 5 times greater than that of water. It says that because of their high degree of toxicity, arsenic, cadmium, chromium, lead and mercury rank among the priority metals of public health significance, and that these elements are considered systemic toxicants known to induce multiple organ damage, even at lower levels of exposure.

They reach people through food, work and smoking. The FDA says metals such as arsenic, lead, cadmium and mercury are present in certain foods because they occur naturally and as environmental pollutants in air, water and soil, and enter the food supply when plants take them up as they grow. For cadmium, the FDA says people can be exposed in occupational settings such as smelting and demolition and in factories that manufacture batteries and electronic plating, and that for smokers, smoking is the primary source of exposure.

Removing metals from the body is a medical treatment. The FDA says chelation involves the use of certain chemicals to remove heavy metals from the body and has been used to treat metal poisoning, and that all FDA-approved chelation products require a prescription because they can only be used safely under the supervision of a healthcare practitioner. It advises consumers to avoid all products offered over the counter for chelation or detoxification, says it is concerned people will delay proven medical care by relying on unproven over-the-counter chelation products, and warns that chelation can result in serious side effects such as dehydration, kidney failure and death.