Chelation therapy is a treatment that involves repeated intravenous (IV) administration of a chemical solution of ethylenediaminetetraacetic acid, or EDTA. It is used to treat acute and chronic lead poisoning by pulling toxins (including heavy metals such as lead, cadmium, and mercury) from the bloodstream. The word chelate comes from the Greek root chele, which means "to claw." EDTA has a claw-like molecular structure that binds to heavy metals and other toxins.
EDTA chelation therapy is approved by the U.S. Food and Drug Administration (FDA) as a treatment for lead and heavy metal poisoning. It is also used as an emergency treatment for hypercalcemia (excessive calcium levels) and the control of ventricular arrhythmias (abnormal heart rhythms) associated with digitalis toxicity.
Studies by the National Academy of Sciences/National Research Council in the late 1960s indicated that EDTA was considered possibly effective in the treatment of arteriosclerosis (blocked arteries). However, most well-designed studies have found that it is not effective for heart disease. In fact, many medical organizations including the National Institutes of Health (NIH), the American Medical Association (AMA), the American Heart Association (AHA), and the American College of Cardiology (ACC) have publicly criticized and denounced the practice of EDTA chelation therapy for heart disease.
Proponents of chelation therapy for heart disease claim that EDTA, combined with oral vitamins and minerals, helps dissolve plaques and mineral deposits associated with atherosclerosis (hardening of the arteries). But most reports about using chelation for heart disease have been based on case studies and a few animal studies that may not apply to people. Also, several large-scale clinical trials published in peer-reviewed journals have found that EDTA chelation therapy is no better than placebo in improving symptoms of heart disease. Some medical experts note that the theories about why chelation might help treat atherosclerosis depend on an outdated understanding of how heart disease develops (see Uses section). Finally, and probably most important, the safety of EDTA chelation therapy for people with heart disease is not known.
The NIH National Center for Complementary and Alternative Medicine (NCCAM) is currently funding a study to examine whether EDTA is effective for heart disease. Results are expected in a few years.
Lead poisoning and heavy metal toxicity
Chelation therapy using EDTA is the medically accepted treatment for lead poisoning. EDTA is injected intravenously and once in the bloodstream, it traps lead and other metals, forming a compound that the body can get rid of in the urine. The process generally takes between 1 - 3 hours. Other heavy metal poisonings treated with chelation include mercury, arsenic, aluminum, chromium, cobalt, manganese, nickel, selenium, zinc, tin, and thallium. Chelating agents other than EDTA are also used to clear several of these substances from the bloodstream.
Heavy metal toxicity in humans has been associated with many health conditions, including heart disease, attention deficit/hyperactivity disorder (ADHD), Alzheimer's disease, immune system disorders, gastrointestinal disorders (including irritable bowel syndrome or IBS), and autism.
EDTA has also been used to treat digoxin toxicity, although most doctors prefer to use other methods. In this case, EDTA helps remove excess levels of digoxin, a medication that is used to treat abnormal rhythms of the heart.
So far, there is no good evidence that EDTA chelation therapy is effective for heart disease. Proponents believe it may help people with atherosclerosis (hardening of the arteries) or peripheral vascular disease (decreased blood flow to the legs) by clearing clogged arteries and improving blood flow. However, a few studies that seem to show it may help have been poorly designed, making the results questionable.
The theory that EDTA clears clogged arteries and improves blood flow is based on an outdated model about what causes heart disease. Other newer theories include the possibility that EDTA functions like an antioxidant, preventing damaging molecules known as free radicals from injuring blood vessel walls and allowing plaque to build up. These ideas are just theories, however.
Most good clinical studies examining EDTA chelation therapy for heart disease and vascular disorders have found that it is no better than placebo. For example, one scientifically rigorous study comparing EDTA chelation therapy to placebo in 84 people with heart disease concluded that those receiving EDTA chelation did no better than those receiving placebo in terms of changes in exercise capacity and quality of life. Several studies evaluating EDTA chelation therapy for peripheral vascular disease did not find any difference between those receiving EDTA and those receiving placebo.
The most common side effect is a burning sensation at the site of the injection. In addition, some people may have an allergic reaction to EDTA. Other serious side effects that have been reported include low blood sugar, diminished calcium levels, headache, nausea, dangerously low blood pressure, kidney failure, organ damage, irregular heartbeat, seizures, or even death.
According to the Centers for Disease Control and Prevention (CDC), there have been deaths associated with hypocalcemia (low levels of calcium) from intravenous chelation therapy.
A qualified health care provider will monitor blood pressure, blood glucose, cholesterol, organ function, and other vital statistics during treatment with EDTA. EDTA may lower levels of nutrients such as calcium and zinc. Blood tests are performed to monitor vitamin and mineral levels before, during, and after EDTA chelation therapy. Supplements of vitamins and minerals, either orally or intravenously, may be given when needed.
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