When medical researchers first investigated the phenomenon known as hardening of the arteries (closely related to
), they discovered that the damaged, brittle vessels found in people with heart disease were lined with calcium deposits. Naturally, this finding inspired the notion that calcium deposits were the cause of the problem.
Some early researchers investigated the possible therapeutic effect of removing such deposits. However, subsequent research indicated that the calcium deposits of atherosclerosis were a symptom rather than a cause, and mainstream interest turned elsewhere. Certain physicians nonetheless maintained an interest in removing calcium; thus chelation therapy was born.
Chelation therapy for heart disease consists of intravenous infusions of a chemical called EDTA (ethylenediaminetetraacetic acid). This synthetic substance is used in conventional medicine to remove heavy metals, such as lead, from the body, but it also has an effect on calcium, which is why it came into use in chelation therapy.
Proponents claim that EDTA chelation is an effective alternative to heart surgery, and that it also offers many other health benefits. To support this, they cite numerous anecdotes of cures apparently brought about by its use. However, anecdotes cannot possibly prove a treatment effective. (For a detailed explanation of why this is the case, see
Why Does This Database Rely on Double-blind Studies?
double-blind, placebo-controlled trials
can do so, and thus far such studies have failed to find chelation therapy effective.
In 2000, a highly respected researcher reviewed the literature on chelation therapy and concluded, “The most striking finding is the almost total lack of convincing evidence for efficacy…. Only 2 controlled clinical trials were located. They provide no evidence that chelation therapy is efficacious beyond a powerful placebo effect…. Given the potential of chelation therapy to cause severe adverse effects, this treatment should now be considered obsolete.”
Subsequent to this review, a well-designed study compared chelation therapy to placebo in 84 people with coronary artery disease.
People receiving EDTA chelation showed improvement however, those receiving placebo also improved—to the same extent! This finding reminds us why double-blind, placebo-controlled studies are necessary to establish the effectiveness of a treatment. If researchers had performed this study without a placebo group, they might have concluded that EDTA chelation really works. Instead, the fact that the same level of benefits was seen in the fake-treatment group indicates that chelation therapy does not work.
Another double-blind study evaluated the potential benefits of chelation therapy when added to conventional therapy in the treatment of people with coronary artery disease.
Researchers were looking for improvements in the ability of a blood vessel in the arm (the brachial artery) to dilate, but did not find any. However, this study had several limitations in its design, making its results less meaningful than they might have been.
The TACT trial included 1,708 patients who had a heart attact within the past six weeks. The group was randomized to ETDA chelation for 30 weeks (via IV) or placebo. Although there were modest improvements in revascularization rates (which reduce the risk of another cardiovascular event), the study had several limitations. Only 65% of patients received all 40 treatments and 17% dropped out. The primary outcome was a composite of several outcomes combined together rather than as one, making it difficult to make a conclusion about chelation's effect. In the end, though there were some improvements seen, there wasn't enough to support the use of chelation therapy as a treatment. More research is needed.4
This treatment is generally given in a series of 10 to 30 sessions. If the practitioner fails to take proper precautions, severe adverse consequences, such as kidney damage, may result. While it appears to be the case that properly performed chelation therapy is unlikely to cause harm, we do not see any justification for using such an invasive method, in the absence of evidence that it will help.