Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. Chelation therapy has a long history of use in clinical toxicology and remains in use for some very specific medical treatments, although it is administered under very careful medical supervision due to various inherent risks, including the mobilization of mercury and other metals through the brain and other parts of the body by the use of weak chelating agents that unbind with metals before elimination, exacerbating existing damage. To avoid mobilization, some practitioners of chelation use strong chelators, such as selenium, taken at low doses over a long period of time.
Chelation therapy also has a history of fraudulent use in alternative medicine, to treat claimed effects of heavy-metal exposure on problems as disparate as heart disease, cancer, and autism.
Chelation therapy must be administered with care as it has a number of possible side effects, including death. In response to increasing use of chelation therapy as alternative medicine and in circumstances in which the therapy should not be used in conventional medicine, various health organizations have confirmed that medical evidence does not support the effectiveness of chelation therapy for any purpose other than the treatment of heavy metal poisoning.
Medical uses
Chelation therapy is the preferred medical treatment for metal poisoning, including acute mercury, iron (including in cases of sickle-cell disease and thalassemia), arsenic, lead, uranium, plutonium and other forms of toxic metal poisoning. The chelating agent may be administered intravenously, intramuscularly, or orally, depending on the agent and the type of poisoning.
Chelating agents
There are a variety of common chelating agents with differing affinities for different metals, physical characteristics, and biological mechanism of action. For the most common forms of heavy metal intoxication – lead, arsenic, or mercury – a number of chelating agents are available. Dimercaptosuccinic acid (DMSA) has been recommended by poison control centers around the world for the treatment of lead poisoning in children. Other chelating agents, such as 2,3-dimercaptopropanesulfonic acid (DMPS) and alpha lipoic acid (ALA), are used in conventional and alternative medicine. Some common chelating agents are ethylenediaminetetraacetic acid (EDTA), 2,3-dimercaptopropanesulfonic acid (DMPS), and thiamine tetrahydrofurfuryl disulfide (TTFD). Calcium-disodium EDTA and DMSA are only approved for the removal of lead by the Food and Drug Administration while DMPS and TTFD are not approved by the FDA. These drugs bind to heavy metals in the body and prevent them from binding to other agents. They are then excreted from the body. The chelating process also removes vital nutrients such as vitamins C and E, therefore these must be supplemented.
The German Environmental Agency (Umweltbundesamt) listed DMSA and DMPS as the two most useful and safe chelating agents available.
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! Chelator !! Used in
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| Ethylenediaminetetraacetic acid (EDTA)
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- early chelation-therapy research
- acute mercury poisoning
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Side effects
Chelation therapy carries a range of potential side effects. When administered appropriately under medical supervision, side effects may include dehydration, hypocalcemia (low calcium levels), renal impairment, elevated liver enzymes, electrolyte imbalance, and allergic reactions. The loss of essential dietary elements such as zinc, magnesium, and iron is common, especially with prolonged therapy, potentially leading to fatigue, weakened immunity, or neurological disturbances.
In contrast, inappropriate or non-medical use for example, in unapproved treatments for autism or cardiovascular disease, has been associated with serious complications, including severe hypocalcemia, neurodevelopmental disorders, and even death. Notably, disodium EDTA had been linked to fatal outcomes when used incorrectly, such as through rapid IV administration. For these reasons, regulating authorities like FDA, CDC strongly discourage off label or unsupervised use of chelation agents.
Use in alternative medicine
In alternative medicine, some practitioners claim chelation therapy can treat a variety of ailments, including heart disease and autism. Chelation therapy prior to heavy metal testing can artificially raise urinary heavy metal concentrations ("provoked" urine testing) and lead to inappropriate and unnecessary treatment. The American College of Medical Toxicology and the American Academy of Clinical Toxicology warn the public that chelating drugs used in chelation therapy may have serious side effects, including liver and kidney damage, blood pressure changes, allergies and in some cases even death of the patient. In the 1980s-2000s, its practitioners estimated that between 100,000 and 200,000 Americans per year were undergoing chelation therapy for heart disease, at a cost of about $5,000 per course of treatment. However, a large-scale clinical study published in 2012 did find a modest benefit from chelation therapy in improving outcomes for patients with a prior heart attack.
In the 1990s and early 2000s, the weight of scientific evidence was against any benefit of chelation therapy for heart disease.
In 1998, the U.S. Federal Trade Commission (FTC) charged a chelation-advocacy group, the "American College for Advancement in Medicine" (ACAM), with making false or unsubstantiated claims when they promoted chelation therapy for heart disease on their website and on a brochure they published. In December 1998, the FTC announced that it had secured a consent agreement barring ACAM from making claims that chelation therapy is effective against atherosclerosis or any other disease of the circulatory system.
However, in 2003-2012, the National Institutes of Health (NIH) sponsored a $30 million controlled trial of chelation therapy, conducted by their National Center for Complementary and Alternative Medicine (NCCAM). This was known as the Trial to Assess Chelation Therapy or TACT. In contrast to prior controlled studies that had produced negative findings, the TACT trial found that chelation therapy modestly improves outcomes for patients with a prior heart attack or history of heart attacks, and markedly improves outcomes if the patients were also diabetic.
In the leadup to the TACT trial, NCCAM Director Stephen E. Straus cited the "widespread use of chelation therapy in lieu of established therapies, the lack of adequate prior research to verify its safety and effectiveness, and the overall impact of coronary artery disease" as factors motivating the trial.
Patient enrollment was to be completed around July 2009 with final completion around July 2010,
At the time of suspension, the trial was criticized for other methodological flaws, including being conducted by "fringe" clinicians, and lacking prior Phase I and II studies. However, the American College of Cardiology supported the trial. Critics of the study characterized it as showing no support for the use of chelation therapy in coronary heart disease, particularly the claims that chelation reduces the need for coronary bypass surgeries.
After the TACT study, further controlled studies in 2015-2022 concluded with cautious endorsements of chelation therapy for heart disease, particularly in patients with diabetes mellitus and prior heart attacks. However, an attempt to replicate the results of the TACT trial in diabetics with prior heart attacks failed to find any benefit.
Autism
According to Quackwatch, autism is one of the conditions for which chelation therapy has been falsely promoted as effective, and practitioners falsify diagnoses of metal poisoning to trick parents into having their children undergo the risky process. , up to 7% of children with autism worldwide The death of two children in 2005 was caused by the administration of chelation treatments, according to the American Center for Disease Control. One of them had autism. Parents either have a doctor use a treatment for lead poisoning, or buy unregulated supplements, in particular DMSA and lipoic acid. There is little to no credible scientific research that supports the use of chelation therapy for the effective treatment of autism.
Deaths from chelation therapy
In August 2005, a five-year-old boy with autism died while undergoing chelation therapy. Only the three-year-old girl had been found to have an elevated blood lead level and resulting low iron levels and anemia, which is the conventional medical cause for administration of chelation therapy.
According to protocol, EDTA should not be used in the treatment of children. More than 30 deaths have been recorded in association with IV-administered disodium EDTA since the 1970s. Munz was looking for a replacement for citric acid as a water softener. Clarke subsequently administered chelation therapy to patients with angina pectoris and other occlusive vascular disease and published his findings in The American Journal of the Medical Sciences in December 1956. He hypothesized that "EDTA could dissolve disease-causing plaques in the coronary systems of human beings." In a series of 283 patients treated by Clarke et al. From 1956 to 1960, 87% showed improvement in their symptomatology. DMSA quickly replaced both BAL and EDTA as the primary treatment for lead, arsenic and mercury poisoning in the United States. Esters of DMSA have been developed which are reportedly more effective; for example, the monoisoamyl ester (MiADMSA) is reportedly more effective than DMSA at clearing mercury and cadmium. 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 harmlessly.
In 1973, a group of practicing physicians created the Academy of Medical Preventics, later renamed the American College for Advancement in Medicine (ACAM). Members of the academy continued to use EDTA therapy for the treatment of vascular disease and developed safer administration protocols. In 1999, the ACAM agreed to stop presenting chelation therapy as effective in treating heart disease, avoiding legal proceedings. In 2010 the U.S. Food and Drug Administration (FDA) warned companies who sold over-the-counter (OTC) chelation products and stated that such "products are unapproved drugs and devices and that it is a violation of federal law to make unproven claims about these products. There are no FDA-approved OTC chelation products."