Chelation treatment is a medical procedure used to remove heavy metals from the bloodstream. It is used to treat conditions such as lead poisoning, mercury poisoning, and other cases in which a heavy metal has built up to a toxic level in the body. Chelation treatment originally was developed after World War I to treat exposure to arsenic-based poison gases used in combat. After World War II, additional chelation methods were developed to treat lead poisoning.
The mechanism behind chelation therapy involves the reaction between the agents used to treat this type of heavy metal poisoning and the metals themselves. Chelating agents bind to the heavy metals, causing them to become water-soluble. The body then is able to filter them out of the bloodstream. For example, in lead chelation, ethylenediaminetetraacetic acid (EDTA) can be used to bond to lead. Dimercaptosuccinic acid (DMSA) also is commonly used in lead chelation treatment.
Heavy metal chelation is the most common medical application of chelation treatment. In addition to lead, mercury, and arsenic, chelation can be used to treat poisoning from plutonium, uranium, and other toxic metals. Intravenous or oral chelation can be used, depending on the type of poisoning being treated and the type of chelate used in the treatment. Intravenous chelation typically takes about two to three hours to complete a full treatment. Another way to administer the appropriate chelate is with a transdermal patch.
Because of the tendency of EDTA to also bond with calcium, use of chelation therapy has been proposed as a possible remedy for atherosclerosis. In atherosclerosis, the arteries become lined and constricted by arterial plaque. One of the major components of this plaque is calcium. However, the American Heart Association and other medical organizations have not endorsed the use of EDTA, citing lack of scientific evidence for its effectiveness.
Other claims for chelation therapy include use in treating autism, presumably by removing mercury from the system. Again, medical professionals have not yet been able to definitively confirm a connection between exposure to mercury and the development of autism. There also seems to be a lack of evidence that chelation can reverse autism. The majority of evidence for this application, as well as evidence regarding atherosclerosis treatment, is anecdotal. In addition, chelation treatment in some cases can produce serious side effects such as kidney and liver damage, and so should be pursued with caution and under the supervision of a qualified medical professional.