Chelation therapy: Encyclopedia - Chelation therapy

Chelation therapy

Chelation therapy is a process involving the use of chelating agents such as EDTA to remove heavy metals from the body. It has uses in both conventional and alternative medicine.

Chelation therapy - Discovery in medicine

Chelating agents were introduced into medicine as a result of the use of poison gas in World War I. The first widely used chelating agent was called British Anti-Lewisite, or BAL, a name given to dimercaprol. It is an organic compound related to the mercaptans, which are a class of sulfur-containing organic compounds. The name comes from their ability to react and form compounds with, or "capture," mercury. Lewisite gas was an arsenic based organic compound used in gas warfare; BAL bound the arsenic compounds from lewisite in the body and enabled it to be excreted harmlessly.

After the metal capturing effects of BAL, a group of chelating agents was discovered. The chelating agents proper bind with metallic ions so that the ion is held by several chemical bonds, thus rendering it much less chemically reactive and allowing the ion to be excreted harmlessly.

Chelation therapy - Uses in conventional medicine

Heavy metal poisoning is an uncommon medical condition that can have significant effects on nearly every organ system [1]. Mercury, for example, has been strongly implicated as "a potential etiological factor in neurodegeneration" [2]. Chelation therapy is used as a treatment for acute mercury, iron, arsenic, lead, plutonium and other forms of heavy metal poisoning, where the amounts are so high that there is enough risk to the health of the patient to justify the therapy. The buildup of iron in thalassemia has led to use in treatment of that disease as well.

Common chelating agents include deferoxamine, dimercaptosuccinic acid (DMSA), D-penicillamine, dimercaprol (BAL), and calcium disodium versante (CaNa₂-EDTA). The choice of chelating agent depends on which metal is involved. The chelating agent may be administered intravenously, intramuscularly, or orally, depending on the agent and the type of poisoning.

One example of successful chelation therapy is the case of Harold McCluskey, a nuclear worker who became very badly contaminated internally with americium in 1976. He was treated with diethylene triamine pentaacetic acid (DTPA) over many years to remove americium from his body. While it was not possible to remove all of the americium, it was possible to mitigate the effects of the accident. Harold McCluskey had 41 MBq (1.1 mCi) of ²⁴¹Am removed from his body, a significant proportion. Harold McCluskey died of unrelated causes 11 years after being contaminated.

The calcium salt of diethylene triamine pentaacetic acid can be used to reduce the amount of plutonium retained in the human body by a factor of about 10 if it is given within about 20 minutes of plutonium entering an open wound. For long term treatment, the zinc salt should be used as this removes fewer vital trace metals from the body.

Chelation therapy - Uses in alternative medicine

Some alternative practitioners believe intravenous chelation therapy "reverses and slows the progression of atherosclerosis and other age-related and degenerative diseases" [3], such as coronary artery disease and macular degeneration. Advocates believe that autism, a neurodevelopmental disorder that appears in early childhood, might be caused or aggravated by heavy metal poisoning and might be ameliorated by chelation therapy.

A private corporation calling itself the American College for Advancement in Medicine claims that 800,000 patient visits for chelation therapy, with an average of forty visits per patient, were made in the United States in 1997 [4]. That is about 0.007% of the total US population. They claim that by 2001 that the number of people who have undergone chelation therapy equaled the number of people having had bypass surgery. A May 2004 survey by the National Center for Complementary and Alternative Medicine (NCCAM) estimated that 0.1%, plus or minus 0.02% of the adult US population had used chelation therapy at some point in their life.

The efficacy, safety, and much of the theory behind these practices are disputed by mainstream medicine. In 2001, researchers at the University of Calgary reported that cardiac patients receiving chelation therapy fared no better than those who received placebo treatment [5]. In August 2005, an autistic boy went into cardiac arrest fifty minutes after undergoing chelation therapy. Although the cause of death is still pending the results of further investigation, it has fueled speculation and controversy regarding chelation therapy. If the death was caused by chelation therapy, it would be the first such case since the 1950s. [6]

Chelation therapy - Calcium chelation therapy

Some alternative practitioners use chelation to treat hardening of the arteries. The safety and efficacy of EDTA chelation therapy as a treatment for coronary artery disease are being assessed by NCCAM in a five-year study which began in 2002. [7] [8]

The original theory behind calcium chelation therapy was that EDTA forms a complex with the calcium in the walls of arteries. One problem with this theory is that EDTA cannot penetrate the cell walls in the arteries and therefore cannot get access to the calcium. Another is that it binds preferentially to other metals.

A number of dangers have been associated with the therapy including hypocalcaemia and decreased blood coagulation ability (possibly due to loss of calcium). Also associated with this practice is the risk of leaching of necessary trace metals.

Adapted from the Wikipedia article "Chelation therapy", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki