Chelation therapy is the administration of chelating agents to remove heavy metals from the body.
For the most common forms of heavy metal intoxication—those involving lead, arsenic or mercury—the standard of care in the United States dictates the use of dimercaptosuccinic acid (DMSA).
Other chelating agents, such as 2 (DMPS) and alpha lipoic acid (ALA), are used in conventional and alternative medicine. "Chelation" is pronounced "key-LAY-shun."
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, the organic dithiol compound dimercaprol (also named
British Anti-Lewisite or BAL), was used as an antidote to the
arsenic-based poison gas, Lewisite.
The sulphur atoms in BAL's mercaptan groups strongly bond to
the arsenic in Lewisite, forming a water-soluble compound that entered
the bloodstream, allowing it to be removed from the body by the kidneys
and liver. BAL had severe side-effects.
After World War II, a large number of navy personnel
suffered from lead poisoning as a result of their jobs repainting the
hulls of ships. The medical use of EDTA as a lead chelating agent was
introduced. Unlike BAL, it is a synthetic amino acid and contains no
mercaptans. EDTA side effects were not considered as severe as BAL.
In the 1960s, BAL was modified into DMSA, a related dithiol
with far fewer side effects. DMSA quickly replaced both BAL and EDTA,
becoming the US standard of care for the treatment of lead, arsenic, and
mercury poisoning, which it remains today.
Research in the former Soviet Union led to the introduction
of DMPS, another dithiol, as a mercury-chelating agent. The Soviets
also introduced ALA, which is transformed by the body into the dithiol
dihydrolipoic acid, a mercury- and arsenic-chelating agent. DMPS has
experimental status in the US FDA, while ALA is a common nutritional
Since the 1970s, iron chelation therapy has been used as an
alternative to regular phlebotomy to treat excess iron stores in people
Other chelating agents have been discovered. They all
function by making several chemical bonds with metal ions, thus
rendering them much less chemically reactive. The resulting complex is
water-soluble, allowing it to enter the bloodstream and be excreted
Calcium-disodium EDTA chelation is approved by the U.S. Food
and Drug Administration (FDA) for treating lead poisoning and heavy
In 1998, the U.S. Federal Trade Commission (FTC) pursued the
American College for Advancement in Medicine (ACAM), an organization
that promotes "complementary, alternative and integrative medicine" over
their advertising of EDTA chelation therapy, with claims including
"Chelation therapy is a safe, effective and relatively inexpensive
treatment to restore blood flow in victims of atherosclerosis without
surgery." The FTC found that "scientific studies do not prove that EDTA
chelation therapy is an effective treatment for atherosclerosis.", and
that the statements by the ACAM were false. In 1999, the ACAM agreed to
stop misrepresenting chelation therapy as effective in treating heart
disease, avoiding legal proceedings.
This article is licensed under the Creative Commons Attribution-ShareAlike License.
It uses material from the Wikipedia article on
All material adapted used from Wikipedia is available under the terms of the
Creative Commons Attribution-ShareAlike License.
Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.