Other common name(s): none
Scientific/medical name(s): ethylene diamine tetraacetic acid (EDTA), edetate sodium; other drugs for chelation may include succimer (DMSA, 2, 3-dimercaptosuccinic acid), dimercaprol, deferoxamine, and penicillamine
Chelation therapy is a mainstream treatment used to treat poisoning from toxic levels of certain metals. Injections of ethylene diamine tetraacetic acid (EDTA) or other chemicals bind, or chelate, iron, lead, mercury, cadmium, zinc, and some other metals, which are then eliminated from the body. The term “chelation” comes from the Greek word chele, which means “claw,” referring to the way the chemical grabs onto metals. However, the term is also used to promote an alternative therapy that is claimed to treat heart disease, cancer, autism, and other conditions that are not caused by abnormal levels of metals.
Chelation therapy is one of several effective treatments for lead poisoning, poisoning by some other toxic metals, and iron overload due to blood disorders and/or multiple blood transfusions. It also shows some promise for treating heart disease, although further testing is needed. 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 excrete some metals, which can build up to toxic levels 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 them, which helps remove them through urination. Other prescription drugs used to treat poisonings due to specific heavy (high atomic mass) metals include dimercaprol, deferoxamine, and penicillamine.
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, autism, Alzheimer’s disease, and to improve 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.
There are other “chelation therapies” that are sold without prescriptions. These come in different forms, including sprays, suppositories, capsules, liquid drops, and clay baths.
What does it involve?
Chelation therapy is most often given into a vein, either as a short injection or over a period of 2 to 4 hours. A typical treatment cycle may include 20 injections or infusions spread over 10 to 12 weeks. Chelation therapy can also be given by mouth, and some dietary supplements advertise that they work in this way.
Practitioners usually recommend at least 20 to 40 treatments to start; however, some may recommend continued therapy for up to 100 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 researchers wondered if using 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.
More recently, certain companies have begun to sell supplements directly to the public for the purpose of chelation. The FDA has sent warning letters to several marketers telling them to stop advertising these supplements as treatment for serious diseases. They warned consumers that all of the approved chelation agents require a prescription and can’t be purchased without one. The FDA has also found that some of the chelation supplements sold without prescriptions actually contain dangerous prescription drugs.
What is the evidence?
Chelation therapy is a proven treatment for lead poisoning, iron overload due to blood disorders or multiple blood transfusions, and poisoning from some 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 which chelate copper or iron may affect growth of 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. 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 the 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.
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
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.
Older research didn’t offer much support for claims that chelation therapy could help heart disease, but one recent study that suggests it might be useful for some people. A large, placebo-controlled study sponsored in part by the National Center for Complementary and Alternative Medicine started in 2003. Results of this study, called the TACT study, were published in the Journal of the American Medical Association in 2013. The results showed a small reduction in heart problems in heart attack patients who had gotten EDTA compared to those getting the sham infusions. Researchers say that it’s too soon to use chelation as a routine treatment until more studies confirm that it works.
According to the American Heart Association and other respected organizations and experts, scientific evidence now only supports routine use of chelation therapy to treat heavy metal poisoning, including iron overload. Further research is needed to find out which patients might be helped by it after having heart attacks.
Are there any possible problems or complications?
These substances may not have been thoroughly tested to find out how they interact 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. There may also be lesser-known methods used, other than the ones discussed here, which could potentially cause harm. Because of these limitations, any information on ill effects 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 heartbeat, and swelling of the veins. Chelation products, even when used under medical supervision, can cause serious harm, including dehydration, kidney failure, and death. The drugs 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.
Each individual chelating drug can cause its own side effects, such as allergic reactions, coma, seizures, low blood pressure, and infections, and should only be used under close medical supervision. 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.
To learn more
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 American Cancer Society Operational Statement on Complementary and Alternative Methods of Cancer Management
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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: 08/13/2014