Other common name(s): none
Scientific/medical name(s): ethylene diamine tetraacetic acid (EDTA), edetate sodium
Chelation therapy is a mainstream treatment used to treat heavy metal poisoning. However, the term is also used to promote an alternative therapy that is supposed to treat heart disease, cancer, and other conditions. It most often involves the injection of ethylene diamine tetraacetic acid (EDTA), a chemical that binds, or chelates, heavy metals, including iron, lead, mercury, cadmium, and zinc. The term "chelation" comes from the Greek word chele, which means "claw," referring to the way the chemical grabs onto metals.
Chelation therapy is one of several effective treatments for lead poisoning. However, 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.
How is it promoted for use?
Chelation therapy using EDTA has been approved by the U.S. Food and Drug Administration (FDA) as a treatment for lead poisoning for more than forty years. The human body cannot break down heavy metals, which can build up to toxic levels in the body and interfere with normal functioning. EDTA and other chelating drugs lower the blood levels of metals such as lead, mercury, cadmium, and zinc by attaching to the heavy metal molecules, which helps the body remove them through urination.
Because EDTA can reduce the amount of calcium in the bloodstream, some practitioners suggest chelation therapy may help reopen arteries blocked by mineral deposits, a condition called atherosclerosis or hardening of the arteries. They claim it is an effective and less expensive alternative to coronary bypass surgery, angioplasty, and other techniques designed to unclog blocked arteries.
Chelation therapy has also been promoted as an alternative treatment for many unrelated conditions, such as gangrene, thyroid disorders, multiple sclerosis, muscular dystrophy, psoriasis, diabetes, arthritis, Alzheimer’s disease, and the improvement of memory, sight, hearing, and smell.
Some alternative practitioners further claim chelation therapy can be used as a cancer treatment. They claim it can remove "environmental toxins" from the body and block the production of harmful molecules called free radicals that can cause cell damage.
What does it involve?
Chelation therapy is most often given into a vein, either as a short injection or over a period of two to four hours. A typical treatment cycle may include twenty injections or infusions spread over ten to twelve weeks. Chelation therapy can also be given by mouth. Practitioners recommend at least twenty to forty treatments to start; however, some may recommend continued therapy for up to a hundred treatments over a period of several years. Because the therapy removes some important minerals from the body, patients often receive high-dose vitamin and mineral supplements during treatment.
What is the history behind it?
The chemical solution most often used in chelation therapy, EDTA, was first made in Germany in the 1930s. It is now widely accepted as an effective treatment for heavy metal poisoning.
In the 1950s, some scientists theorized that EDTA could remove calcium from the body. Calcium can build up on artery walls, eventually causing heart disease, and it was theorized that use of EDTA could unclog blocked arteries. In some early studies, researchers reported positive results among patients with heart disease who received EDTA. Some said that chelation therapy relieved chest pain caused by blocked arteries. These first observations have not been confirmed by larger, more rigorous studies, but they led some practitioners to begin using chelation therapy for heart and circulatory problems and, later, for several other illnesses. It is estimated that tens of thousands of Americans currently undergo chelation therapy for heart disease.
In 1998, the Federal Trade Commission charged the American College of Advancement in Medicine (ACAM), the principal group promoting chelation therapy, with presenting false advertising and unsubstantiated statements about its benefits. The ACAM agreed to stop publishing any claims that were not based on reliable scientific evidence.
What is the evidence?
Chelation therapy is a proven treatment for lead poisoning and poisoning from other heavy metals. However, available scientific evidence does not support claims that the treatment benefits patients with cancer, heart disease, or any medical problems other than heavy-metal poisoning.
There are no published studies that reliably show benefit from using chelation therapy with EDTA against cancer. Some laboratory studies have suggested that agents other than EDTA that chelate copper or iron may affect cancer cells or the formation of tumor blood vessels. In a small study using mice, researchers studied iron-chelating agents to see if they would reduce the growth of neuroblastoma, a type of cancer in infants and young children. The results, published in 1998, concluded that chelation therapy did not shrink tumors. Few studies of the use of chelation therapy against cancer in humans have been published in peer-reviewed medical journals. These few studies have been small and have not shown a significant level of effectiveness. Research is continuing in this area. A 2006 study found that a new iron chelator called di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone reduced growth of skin cancer cells in mice. However, this experimental treatment has not been tested in humans and is very different from the chelation agents used by alternative practitioners.
Available research does not yet support claims that chelation therapy can treat heart disease. Randomized clinical trials have found that chelation therapy drugs did not benefit patients with impaired circulation in their legs. In 1993, a review of all chelation therapy studies reported during the previous 37 years concluded that scientific data did not support claims that the treatment was useful for treating heart problems. Studies published since then have generally reached the same conclusion. A very large, placebo-controlled study sponsored by the National Center for Complementary and Alternative Medicine is now under way and should provide a more definitive answer as to whether chelation therapy has any effects on heart disease.
According to a number of well-respected organizations, including the American Heart Association, the American Medical Association, the Centers for Disease Control and Prevention, the American Osteopathic Association, the American Academy of Family Physicians, and the FDA, there is no scientific evidence that chelation therapy is an effective treatment for any medical condition except heavy metal poisoning.
Are there any possible problems or complications?
This substance may not have been tested to find out how it interacts with medicines, foods, or dietary supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.
Available scientific evidence does not support claims that chelation therapy is a safe treatment for any type of cancer. Chelation therapy may produce toxic effects, including kidney damage, irregular heart beat, and swelling of the veins. It may also cause nausea, vomiting, diarrhea, and temporary lowering of blood pressure. Since the therapy removes minerals from the body, there is a risk of developing low calcium levels (hypocalcemia) and bone damage. Chelation therapy may also impair the immune system and decrease the body's ability to produce insulin. People may also feel pain at the site of the EDTA injection. Chelation therapy may be dangerous in people with kidney disease, liver disease, or bleeding disorders. Women who are pregnant or breastfeeding should not use this method.
Chelation therapy is often given along with large doses of vitamins and other minerals, which may actually contribute to the processes that produce dangerous free radicals in the body. Loss of zinc can also lead to mutations in cells. For this reason, chelation therapy may actually increase the risk of cancer.
The possible interactions between chelation therapy and prescription or over-the-counter medicines are not entirely known.
Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.
More information from your American Cancer Society
The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).
The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management
Cassileth B. The Alternative Medicine Handbook. New York, NY: W. W. Norton & Co; 1998.
Ernst E, ed. The Desktop Guide to Complementary and Alternative Medicine: An Evidence-Based Approach. London, UK: Mosby; 2001.
Green S. Chelation therapy: Unproven claims and unsound theories. 2002. Accessed at: www.quackwatch.org/01QuackeryRelatedTopics/chelation.html on June 11, 2008.
Grier MT, Meyers DG. So much writing, so little science: a review of 37 years of literature on edetate sodium chelation therapy. Ann Pharmacother. 1993;27:1504-1509.
Guldager B, Jelnes R, Jorgensen SJ, et al. EDTA treatment of intermittent claudication: a double-blind placebo-controlled study. J Intern Med. 1992;231:261-267.
Knudtson ML, Wyse DG, Galbraith PD, Brant R, Hildebrand K, Paterson D, Richardson D, Burkart C, Burgess E. Chelation therapy for ischemic heart disease: a randomized controlled trial. JAMA. 2002;287(4):481-486.
MD Anderson Cancer Center. Comlementary Practice: Chelation (EDTA) Therapy. Accessed at: www.mdanderson.org/departments/cimer/display.cfm?id=4230febd-e954-4025-86affa94c7a8fc71&method=displayfull&pn=6eb86a59-ebd9-11d4-810100508b603a14 on June 21, 2008.
Redman BG, Esper P, Pan Q, et al. Phase II trial of tetrathiomolybdate in patients with advanced kidney cancer. Clin Cancer Res. 2003;9:1666-1672.
Selig RA, White L, Gramacho C, Sterling-Levis K, Fraser IW, Naidoo D. Failure of iron chelators to reduce tumor growth in human neuroblastoma xenografts. Cancer Res 1998;58:473-478.
van Rij AM, Solomon C, Packer SG, Hopkins WG. Chelation therapy for intermittent claudication. A double-blind, randomized, controlled trial. Circulation. 1994;90:1194-1199.
Whitnall M, Howard J, Ponka P, Richardson DR. A class of iron chelators with a wide spectrum of potent antitumor activity that overcomes resistance to chemotherapeutics. Proc Natl Acad Sci U S A. 2006;103:14901-14906
Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.
Last Revised: 11/01/2008