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.
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. Over-the-counter chelation products are not approved for sale in the United States.
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.[clarification needed]
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 for the treatment of lead poisoning in children by poison control centers around the world. 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.
|Dimercaprol (British anti-Lewisite; BAL)|
|Dimercaptosuccinic acid (DMSA)|
|Dimercapto-propane sulfonate (DMPS)|
Occasionally adjunctive therapy in:
|Ethylenediamine tetraacetic acid (calcium disodium versenate) (CaNa2-EDTA)|
|Deferoxamine, Deferasirox and Deferiprone|
When used properly in response to a diagnosis of harm from metal toxicity, side effects of chelation therapy include dehydration, low blood calcium, harm to kidneys, increased enzymes as would be detected in liver function tests, allergic reactions, and lowered levels of dietary elements. When administered inappropriately, there are the additional risks of hypocalcaemia (low calcium levels), neurodevelopmental disorders, and death.
Chelation therapy can be traced back to the early 1930s, when Ferdinand Münz, a German chemist working for I.G. Farben, first synthesized ethylenediaminetetraacetic acid (EDTA). Munz was looking for a replacement for citric acid as a water softener. Chelation therapy itself began during World War II when chemists at the University of Oxford searched for an antidote for lewisite, an arsenic-based chemical weapon. The chemists learned that EDTA was particularly effective in treating lead poisoning.
Following World War II, chelation therapy was used to treat workers who had painted United States naval vessels with lead-based paints. In the 1950s, Norman Clarke, Sr. was treating workers at a battery factory for lead poisoning when he noticed that some of his patients had improved angina pectoris following chelation therapy. 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 1956-1960, 87% showed improvement in their symptomatology. Other early medical investigators made similar observations of EDTA's role in the treatment of cardiovascular disease (Bechtel, 1956; Bessman, 1957; Perry, 1961; Szekely, 1963; Wenig, 1958: and Wilder, 1962).
In 1973, a group of practicing physicians created the Academy of Medical Preventics (now the American College for Advancement in Medicine). The academy trains and certifies physicians in the safe administration of chelation therapy. Members of the academy continued to use EDTA therapy for the treatment of vascular disease and developed safer administration protocols.
In the 1960s, BAL was modified into DMSA, a related dithiol with far fewer side effects. 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. 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 United States, while ALA is a common nutritional supplement.
Since the 1970s, iron chelation therapy has been used as an alternative to regular phlebotomy to treat excess iron stores in people with haemochromatosis. 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.
Calcium-disodium EDTA chelation has been studied by the U.S. National Center for Complementary and Alternative Medicine for treating coronary disease. 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 the claims made regarding the treatment of atherosclerosis in advertisements for EDTA chelation therapy. The FTC concluded that there was a lack of scientific studies to support these claims and that the statements by the ACAM were false. 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."
Society and culture
In 1998, the U.S. Federal Trade Commission (FTC) charged that the web site of the American College for Advancement in Medicine (ACAM) and a brochure they published had made false or unsubstantiated claims. In December 1998, the FTC announced that it had secured a consent agreement barring ACAM from making unsubstantiated advertising claims that chelation therapy is effective against atherosclerosis or any other disease of the circulatory system.
In August 2005, doctor error led to the death of a five-year-old autistic boy who was undergoing chelation therapy. Others, including a three-year-old nonautistic girl and a nonautistic adult, have died while undergoing chelation therapy. These deaths were due to cardiac arrest caused by hypocalcemia during chelation therapy. In two of the cases hypocalcemia appears to have been caused by the administration of Na2EDTA (disodium EDTA) and in the third case the type of EDTA was unknown. Only the 3-year-old girl had 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,[clarification needed] 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.
Use in alternative medicine
In alternative medicine, some practitioners claim chelation therapy can treat a variety of ailments, including heart disease and autism. The use of chelation therapy by alternative medicine practitioners for behavioral and other disorders is considered pseudoscientific; there is no proof that it is effective. In addition to being ineffective, 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.
The American Cancer Society says of chelation therapy: "Available scientific evidence does not support claims that it is effective for treating other conditions such as cancer. Chelation therapy can be toxic and has the potential to cause kidney damage, irregular heartbeat, and even death."
According to the findings of a 1997 systematic review, EDTA chelation therapy is not effective as a treatment for coronary artery disease and this use is not approved in the United States by the US Food and Drug Administration (FDA). Several possible mechanisms for its efficacy have been proposed, though none have been scientifically validated.
The American Heart Association stated in 1997 that there is "no scientific evidence to demonstrate any benefit from this form of therapy." The United States Food and Drug Administration (FDA), the National Institutes of Health (NIH) and the American College of Cardiology "all agree with the American Heart Association" that "there have been no adequate, controlled, published scientific studies using currently approved scientific methodology to support this therapy for cardiovascular disease." They speculate that any improvement among heart patients undergoing chelation therapy can be attributed to the placebo effect and generally recommended lifestyle changes such as "quitting smoking, losing weight, eating more fruits and vegetables, avoiding foods high in saturated fats and exercising regularly." They also are concerned that patients could put off proven treatments for heart disease like drugs or surgery.
A systematic review published in 2005 found that controlled scientific studies did not support chelation therapy for heart disease. It found that very small trials and uncontrolled descriptive studies have reported benefits while larger controlled studies have found results no better than placebo.
In 2009, the Montana Board of Medical Examiners issued a position paper concluding that "chelation therapy has no proven efficacy in the treatment of cardiovascular disease, and in some patients could be injurious."
The U.S. National Center for Complementary and Alternative Medicine (NCCAM) conducted a trial on the chelation therapy's safety and efficacy for patients with coronary artery disease. 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. The study has been criticized by some who said it was unethical, unnecessary and dangerous, and that multiple studies conducted in prior to it demonstrated that the treatment provides no benefit.
The US National Center for Complementary and Alternative Medicine began the Trial to Assess Chelation Therapy (TACT) in 2003. Patient enrollment was to be completed around July 2009 with final completion around July 2010, but enrollment in the trial was voluntarily suspended by organizers in September 2008 after the Office for Human Research Protections began investigating complaints such as inadequate informed consent. Additionally, the trial was criticized for lacking prior Phase I and II studies, and critics summarized previous controlled trials as having "found no evidence that chelation is superior to placebo for treatment of CAD or PVD." The same critics argued that methodological flaws and lack of prior probability made the trial "unethical, dangerous, pointless, and wasteful." The American College of Cardiology supported the trial and research to explore whether chelation therapy was effective in treating heart disease. Evidence of insurance fraud and other felony convictions among (chelation proponent) investigators further undermined the credibility of the trial.
The final results of TACT were published in November 2012. The authors concluded that disodium EDTA chelation "modestly" reduced the risk of adverse cardiovascular outcomes among stable patients with a history of myocardial infarction. The study also showed a "marked" reduction in cardiovascular events in diabetic patients treated with EDTA chelation. An editorial published in the Journal of the American Medical Association said that "the study findings may provide novel hypotheses that merit further evaluation to help understand the pathophysiology of secondary prevention of vascular disease." Critics of the study characterized the study as showing no support for the use of chelation therapy in coronary heart disease, particularly the claims to reduce the need for coronary artery bypass grafting (CABG, pronounced "cabbage").
Quackwatch says that 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. As of 2008[update], up to 7% of children worldwide with autism had been subjected to chelation therapy. 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 was autistic. Parents either have a doctor use a treatment for lead poisoning, or buy unregulated supplements, in particular DMSA and lipoic acid. Aspies For Freedom, an autism rights organization, considers this use of chelation therapy unethical and potentially dangerous. There is little to no credible scientific research that supports the use of chelation therapy for the effective treatment of autism.
- Aaseth, Jan; Crisponi, Guido; Anderson, Ole (2016). Chelation Therapy in the Treatment of Metal Intoxication. Academic Press. p. 388. ISBN 9780128030721.
- "Chelation: Therapy or "Therapy"?". poison.org. National Capital Poison Center. 6 May 2013 . Retrieved 9 October 2013.
- Atwood, K.C., IV; Woeckner, E.; Baratz, R.S.; Sampson, W.I. (2008). "Why the NIH Trial to Assess Chelation Therapy (TACT) should be abandoned". Medscape Journal of Medicine. 10 (5): 115. PMC 2438277. PMID 18596934.
- "Chelation Therapy". American Cancer Society. 1 November 2008. Archived from the original on 5 July 2010. Retrieved 14 September 2013.
- "Deaths Associated with Hypocalcemia from Chelation Therapy - Texas, Pennsylvania, and Oregon, 2003-2005". www.cdc.gov. Retrieved 2016-10-13.
- Food and Drug Administration (FDA) (14 October 2010). "FDA issues warnings to marketers of unapproved 'chelation' products" (Press release). Archived from the original on January 11, 2017.
- Flora, Swaran J. S.; Pachauri, Vidhu (2010-06-28). "Chelation in Metal Intoxication". International Journal of Environmental Research and Public Health. 7 (12): 2745–2788. doi:10.3390/ijerph7072745. PMC 2922724. PMID 20717537.
- Fortin, Patricia M.; Fisher, Sheila A.; Madgwick, Karen V.; Trivella, Marialena; Hopewell, Sally; Doree, Carolyn; Estcourt, Lise J. (May 8, 2018). "Interventions for improving adherence to iron chelation therapy in people with sickle cell disease or thalassaemia". The Cochrane Database of Systematic Reviews. 5: CD012349. doi:10.1002/14651858.CD012349.pub2. ISSN 1469-493X. PMC 5985157. PMID 29737522.
- Hider, Robert C.; Kong, Xiaole (2013). "Chapter 8. Iron: Effect of Overload and Deficiency". In Astrid Sigel, Helmut Sigel and Roland K. O. Sigel (ed.). Interrelations between Essential Metal Ions and Human Diseases. Metal Ions in Life Sciences. 13. Springer. pp. 229–294. doi:10.1007/978-94-007-7500-8_8. PMID 24470094.
- "Natural Standard Professional Monograph". Natural Standard. Retrieved 16 June 2009.[dead link]
- Chisolm, J.J., Jr. (2000). "Safety and efficacy of meso-2,3-dimercaptosuccinic acid (DMSA) in children with elevated blood lead concentrations". Journal of Toxicology: Clinical Toxicology. 38 (4): 365–75. doi:10.1081/CLT-100100945. PMID 10930052.
- Bridges, Sarah (January 2006). "The promise of chelation". Mothering (134). pp. 54–61.[unreliable medical source?]
- Kommission Human-Biomonitoring des Umweltbundesamtes [Human Biomonitoring Committee of the Federal Environmental Agency (Federal Republic of Germany )] (1999). "Bekanntmachung des Umweltbundesamtes Einsatz von Chelatbildnern in der Umweltmedizin? Stellungnahme der Kommission 'Human-Biomonitoring' des Umweltbundesamtes" [Notice of the Federal Environmental Agency use of chelating agents in environmental medicine? Opinion of the Commission 'Human biomonitoring' of the German Federal Environment Agency]. Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz (in German). 42 (10): 823–4. doi:10.1007/s001030050288.
- Masters, Susan B.; Trevor, Anthony J.; Katzung, Bertram G. (2008). Katzung & Trevor's Pharmacology: Examination & Board Review (8th ed.). McGraw Hill Medical. pp. 481–3. ISBN 978-0071488693.
- Crisponi, Guido; Nurchi, Valeria M.; Lachowicz, Joanna (2019). "Chapter 3. Iron Chelation for Iron Overload in Thalassemia". In Sigel, Astrid; Freisinger, Eva; Sigel, Roland K. O.; Carver, Peggy L. (Guest editor) (eds.). Essential Metals in Medicine:Therapeutic Use and Toxicity of Metal Ions in the Clinic. Metal Ions in Life Sciences. 19. Berlin: de Gruyter GmbH. pp. 49–86. doi:10.1515/9783110527872-009. ISBN 978-3-11-052691-2. PMID 30855104.
- American College of Medical Toxicology; American Academy of Clinical Toxicology (February 2013), "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation, American College of Medical Toxicology and American Academy of Clinical Toxicology, retrieved 5 December 2013, which cites
- Kosnett, M J (2010). "Chelation for Heavy Metals (Arsenic, Lead, and Mercury): Protective or Perilous?". Clinical Pharmacology & Therapeutics. 88 (3): 412–415. doi:10.1038/clpt.2010.132. ISSN 0009-9236. PMID 20664538.
- Medical Letter consultants (September 20, 2010). "Nonstandard uses of chelation therapy". The Medical Letter on Drugs and Therapeutics. 52 (1347): 75–6. PMID 20847718.
- Food and Drug Administration (14 October 2010). "Consumer Updates - FDA Warns Marketers of Unapproved 'Chelation' Drugs". fda.gov. Retrieved 3 July 2014.
- "Chemistry in its element: compounds". Royal Society of Chemistry. Retrieved 30 June 2014.
- Heidi Braun Grebe; Philip J. Gregory (2002). "Inhibition of Warfarin Anticoagulation Associated with Chelation Therapy". 22 (8). Pharmacotherapy. Cite journal requires
- Efrain Olszewer; James P. Carter (1988). "EDTA Chelation Therapy in Chronic Degenerative Disease". Medical Hypotheses. 27: 41–49. doi:10.1016/0306-9877(88)90082-5. PMID 3144646.
- M R Lewin (1997). "Chelation therapy for cardiovascular disease. Review and commentary". Tex Heart Inst J. 24 (2): 81–89.
- Ronald L. Hoffman (February 2014). "The facts and fictions of chelation therapy". The Clinical Advisor. Retrieved 30 June 2014.
- Kalia, Kiran; Flora, Swaran J.S. (2005). "Strategies for safe and effective therapeutic measures for chronic arsenic and lead poisoning". Journal of Occupational Health. Japan Society for Occupational Health. 47 (1): 1–21. doi:10.1539/joh.47.1. PMID 15703449.
- "Treatment & Management: Monitoring Treatment", Hemochromatosis for healthcare professionals, Division of Nutrition and Physical Activity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, U.S. Dept. of Health and Human Services, 1 November 2007, archived from the original on 2008-02-24, retrieved 29 March 2008
- "Questions and Answers: The NIH Trial of EDTA Chelation Therapy for Coronary Artery Disease". National Center for Complementary and Alternative Medicine (NCCAM), National Institutes of Health, U.S. Dept. of Health and Human Services. March 2007. Archived from the original on 2007-10-15. Retrieved 11 November 2007.
- "American College for Advancement in Medicine: Case Timeline" (FTC Case Timeline with links to documents). Federal Trade Commission (FTC). 13 July 1999. Retrieved 1 July 2010.
- "United States of America Federal Trade Commission In the Matter of American College for Advancement in Medicine, a corporation. File no. 962 3147. Agreement Containing Consent Order". Federal Trade Commission. 12 January 1998. Retrieved 1 July 2010. "Attachment A" (Notification letter).
- Federal Trade Commission (8 December 1998). "Medical Association Settles False Advertising Charges Over Promotion of 'Chelation Therapy'" (Press release). Retrieved 17 January 2014.
- Brown, M.J.; Willis, T.; Omalu, B.; Leiker, R. (2006). "Deaths resulting from hypocalcemia after administration of edetate disodium: 2003–2005". Pediatrics. 118 (2): e534–6. doi:10.1542/peds.2006-0858. PMID 16882789.
- Baxter, A.J.; Krenzelok, E.P. (2008). "Pediatric fatality secondary to EDTA chelation". Clinical Toxicology. 46 (10): 1083–4. doi:10.1080/15563650701261488. PMID 18949650.
- "Deaths associated with hypocalcemia from chelation therapy - Texas, Pennsylvania, and Oregon, 2003-2005". Morbidity and Mortality Weekly Report. Centers for Disease Control and Prevention. 55 (8): 204–7. 2006.
- Van der Schaar, Peter J. (2011). Textbook of Clinical Metal Toxicology (10th ed.). Leende, Netherlands: International Board of Clinical Metal Toxicology.[unreliable medical source?][full citation needed]
- Ernst, E. (2000). "Chelation therapy for coronary heart disease: An overview of all clinical investigations". American Heart Journal. 140 (1): 139–41. doi:10.1067/mhj.2000.107548. PMID 10874275.
- Weber, W.; Newmark, S. (2007). "Complementary and alternative medical therapies for attention-deficit/hyperactivity disorder and autism". Pediatric Clinics of North America. 54 (6): 983–1006. doi:10.1016/j.pcl.2007.09.006. PMID 18061787.
- "Boy with autism dies during 'chelation therapy'". Behavior News. Behavior Analysis Association of Michigan. 30 August 2005. Archived from the original on 29 November 2016. Retrieved 4 August 2010.
- American College of Medical Toxicology; American Academy of Clinical Toxicology (February 2013), "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation, American College of Medical Toxicology and American Academy of Clinical Toxicology, retrieved 5 December 2013
- Ernst, Edzard (1997). "Chelation therapy for peripheral arterial occlusive disease: A systematic review". Circulation. 96 (3): 1031–3. doi:10.1161/01.CIR.96.3.1031. PMID 9264515.
- Seely, D.M.; Wu, P.; Mills, E.J. (2005). "EDTA chelation therapy for cardiovascular disease: A systematic review". BMC Cardiovascular Disorders. 5: 32. doi:10.1186/1471-2261-5-32. PMC 1282574. PMID 16262904.
- Montana Board of Medical Examiners (BME) (14 May 2009). "EDTA Chelation for Cardiovascular Disease" (PDF) (BME Position Paper). Business Standard Div., Montana Dept. of Labor and Industry. Archived from the original (PDF) on 2010-02-04.
- "Trial to Assess Chelation Therapy (TACT)". ClinicalTrials.gov. U.S. National Library of Medicine, National Institutes of Health, U.S. Dept. of Health and Human Services. August 2013.
- National Institutes of Health (NIH); National Center for Complementary and Alternative Medicine; National Heart, Lung, and Blood Institute (7 August 2002). "NIH Launches Large Clinical Trial on EDTA Chelation Therapy for Coronary Artery Disease". NIH News (Press release). (NIH). Archived from the original on 28 December 2014. Retrieved 28 December 2008.CS1 maint: multiple names: authors list (link)
- "Government probes chelation-heart disease study". Washington Post. Washington, DC. Associated Press. 2008-09-25. Retrieved 2008-09-26.
- Jones, Valerie (2009-07-09). "NIH Awards $30 Million Research Dollars To Convicted Felons: Cliff's Notes Version". Science-Based Medicine. Retrieved December 5, 2014.
- Gervasio D. Lamas (2013). "Effect of Disodium EDTA Chelation Regimen on Cardiovascular Events in Patients With Previous Myocardial Infarction: The TACT Randomized Trial". JAMA. 309 (12): 1241–1250. doi:10.1001/jama.2013.2107. PMC 4066975. PMID 23532240.
- Escolar, E.; Lamas, G. A.; Mark, D. B.; Boineau, R.; Goertz, C.; Rosenberg, Y.; Nahin, R. L.; Ouyang, P.; Rozema, T.; Magaziner, A.; Nahas, R.; Lewis, E. F.; Lindblad, L.; Lee, K. L. (2014). "The Effect of an EDTA-based Chelation Regimen on Patients With Diabetes Mellitus and Prior Myocardial Infarction in the Trial to Assess Chelation Therapy (TACT)". Circulation: Cardiovascular Quality and Outcomes. CircoutComes. 7 (1): 15–24. doi:10.1161/CIRCOUTCOMES.113.000663. PMC 4111470. PMID 24254885.
- Bauchner H; Fontanarosa PB; Golub RM (2013). "Evaluation of the Trial to Assess Chelation Therapy (TACT): The Scientific Process, Peer Review, and Editorial Scrutiny". JAMA. 309 (12): 1291–1292. doi:10.1001/jama.2013.2761. PMID 23532245.
- Atwood, Kimball (4 November 2012). "The Trial to Assess Chelation Therapy: Equivocal as Predicted". Science-Based Medicine.
- Gorski, David (5 November 2012). "The result of the Trial to Assess Chelation Therapy (TACT): As underwhelming as expected". Science-Based Medicine.
- "Chelation therapy doesn't alter quality of life in heart attack patients". American Heart Association. 4 November 2012. Archived from the original on 9 November 2012. Retrieved 30 November 2012.
- "Why Chelation Therapy Should Be Avoided". Quackwatch. 15 May 2004. Retrieved 7 October 2013.
- Davis, Tonya N.; O’Reilly, Mark; Kang, Soyeon; Lang, Russell; et al. (2013). "Chelation treatment for autism spectrum disorders: A systematic review". Research in Autism Spectrum Disorders. 7 (1): 49–55. doi:10.1016/j.rasd.2012.06.005.
However, given the significant methodological limitations of these studies, the research reviewed here does not support the use of chelation as a treatment for ASD
- Stokstad, E. (2008). "Stalled trial for autism highlights dilemma of alternative treatments". Science. 321 (5887): 326. doi:10.1126/science.321.5887.326. PMID 18635766.
- "FDA links child deaths to chelation therapy". NBC News / Associated Press. February 3, 2006. Archived from the original on August 30, 2018. Retrieved August 30, 2018.
- "Aspies For Freedom". Aspies For Freedom. Archived from the original on 2010-01-17. Retrieved 24 February 2009.
- Blakeslee, Sandra (19 May 2004). "Panel finds no evidence to tie autism to vaccines". New York Times. Retrieved 2008-02-01.
- Blaucok-Busch, E.; Amin, O.R.; Dessoki, H.H.; Rabah, T. (2012). "Efficacy of DMSA therapy in a sample of Arab children with autistic spectrum disorder". Mædica. 7 (3): 214–21. PMC 3566884. PMID 23400264.
- Adams, J.B.; Baral, M.; Geis, E.; Mitchell, J.; et al. (2009). "Safety and efficacy of oral DMSA therapy for children with autism spectrum disorders: Part B - Behavioral results". BMC Clinical Pharmacology. 9: 17. doi:10.1186/1472-6904-9-17. PMC 2770991. PMID 19852790.
- Adams, J.B.; Baral, M.; Geis, E.; Mitchell, J.; et al. (2009). "The severity of autism is associated with toxic metal body burden and red blood cell glutathione levels". Journal of Toxicology. 2009: 532640. doi:10.1155/2009/532640. PMC 2809421. PMID 20107587.
- Adams, J.B.; Baral, M.; Geis, E.; Mitchell, J.; et al. (2009). "Safety and efficacy of oral DMSA therapy for children with autism spectrum disorders: Part A - Medical results". BMC Clinical Pharmacology. 9: 16. doi:10.1186/1472-6904-9-16. PMC 2774660. PMID 19852789.