Overview:

Chelation therapy is a treatment that  involves repeated administration of the amino acid ethylenediaminetetraacetic acid, or EDTA. It is used to treat acute and chronic  lead poisoning by pulling toxins (including heavy metals such as lead, cadmium,  and mercury) from the bloodstream. The word chelate comes from the Greek root  chele, which means “to claw.” EDTA has a claw like molecular structure that  binds to heavy metals and other toxins.

EDTA chelation therapy is approved by  the U.S. Food and Drug Administration (FDA) as a treatment for lead and heavy  metal poisoning. It is also used as an emergency treatment for hypercalcemia  (excessive calcium levels) and the control of ventricular arrhythmias (abnormal  heart rhythms) associated with digitalis toxicity.

Studies by the National Academy of  Sciences/National Research Council in the late 1960s indicated that EDTA was  considered possibly effective in the treatment of arteriosclerosis (blocked  arteries). However, most well designed studies have found that it is not  effective for heart disease. In fact, many medical organizations — including  the National Institutes of Health (NIH), the American Medical Association (AMA),  the American Heart Association (AHA), and the American College of Cardiology  (ACC) — have publicly criticized and denounced the practice of EDTA chelation  therapy for heart disease.

Proponents of chelation therapy for  heart disease claim that EDTA, combined with oral vitamins and minerals, helps  dissolve plaques and mineral deposits associated with atherosclerosis (hardening  of the arteries). But most reports about using chelation for heart disease have  been based on case studies and a few animal studies that may not apply to  people. Also, several large scale clinical trials published in peer reviewed  journals have found that EDTA chelation therapy is no better than placebo in  improving symptoms of heart disease. Some medical experts note that the theories  about why chelation might help treat atherosclerosis depend on an outdated  understanding of how heart disease develops (see Uses section). Finally, and  probably most important, the safety of EDTA chelation therapy for people with  heart disease is not known.

The NIH National Center for  Complementary and Alternative Medicine (NCCAM) is funding a study to examine  whether EDTA is effective for heart disease. Results are expected in a few  years.

Atherosclerosis

So far, there is no good evidence that  EDTA chelation therapy is effective for heart disease. Proponents believe it may  help people with atherosclerosis (hardening of the arteries) or peripheral  vascular disease (decreased blood flow to the legs) by clearing clogged arteries  and improving blood flow. However, the few studies that show it may help have  been poorly designed, making the results questionable.

The theory that EDTA clears clogged  arteries and improves blood flow is based on an outdated model about what causes  heart disease. Other newer theories include the possibility that EDTA functions  like an antioxidant, preventing damaging molecules known as free radicals from  injuring blood vessel walls and allowing plaque to build up. These ideas are  just theories, however.

Most good clinical studies examining EDTA  chelation therapy for heart disease and vascular disorders have found that it is  no better than placebo. For example, one scientifically rigorous study comparing  EDTA chelation therapy to placebo in 84 people with heart disease concluded that  those receiving EDTA chelation did no better than those receiving placebo in  terms of changes in exercise capacity and quality of life. Several studies  evaluating EDTA chelation therapy for peripheral vascular disease did not find  any difference between those receiving EDTA and those receiving placebo.

Excerpted from University of Maryland medical center http://www.umm.edu/altmed/articles/ethylenediaminetetraacetic-acid-000302.htm