5X5 Episode 95
|5X5 Episode 95|
|21st September 2010|
|5X5 94||5X5 96|
|S: Steven Novella|
|R: Rebecca Watson|
|B: Bob Novella|
|J: Jay Novella|
|E: Evan Bernstein|
You're listening to the Skeptics' Guide 5x5, five minutes with five skeptics, with Steve, Jay, Rebecca, Bob and Evan.
S: This is the SGU 5X5 and tonight we're talking about chelation therapy. Now, chelation therapy is interesting because it's an actual legitimate FDA-approved medical intervention. It is used legitimately to treat things like heavy-metal poisoning. But it has also been a focus for a very long time, for decades in fact, of interest in fringe use; use for unapproved and not evidence-based indications, beginning with the treatment for heart disease.
E: Chelation was introduced as a remedy in the 1920s as an antidote to the arsenic-based poison gas lewisite, which was used in World War I. British anti-Lewisite, or BAL, was the first widely used chelation agent. After World War II, a large number of navy personnel suffered from lead poisoning as a result of their jobs repainting the hulls of ships. The medical use of Ethylenediaminetetraacetic acid, or EDTA, was introduced at this time. The side effects of EDTA were considered not as severe as BAL. Around the 1960s, after EDTA was found effective in chelating or removing toxic metals from the blood, some scientists had postulated that hardened arteries could be softened if the calcium in their walls was removed. But later evidence concluded that EDTA chelation used in this study was not a useful clinical tool in the treatment of coronary disease. Soon afterwards, BAL was modified into Dimercaptosuccinic acid (DMSA), which was similar to BAL but it had far fewer side effects. DMSA quickly replaced BAL and is used along with EDTA, becoming the US standard of care for the treatment of lead, arsenic, and mercury poisoning, which remains that way today.
B: Chelation therapy has actually had legitimate medical uses for almost a centurie. Chelating agents were first used in World War I to deal with arsenic-based poison gas that was used. And after World War II, chelation was used on men with lead poisoning from painting the hulls of ships. It is commonly used now to treat many types of poisons like arsenic, lead, uranium, plutonium and others. Depending on various factors, it could be given through an IV, intramuscularly or even orally. Some very common chelation agents include dimercaprol, which is used for arsenic poisoning and mercury poisoning and lead poisoning, and another common one is called penicillamine, which is used for copper toxicity. So basically these chelating agents work by binding to the metal in the body that they want to get rid of, and basically it just flushes it out with your urine.
R: Unfortunately, despite the actual uses of chelation—the beneficial uses of chelation, there are some alternative medicine practitioners who claim that it can be used to cure cancer by removing toxins from the body. And of course, these toxins are rather ill-defined. But that doesn't stop them from saying that it can help. There's absolutely no evidence to suggest that this works and unfortunately this sort of thing can encourage people to give up on real treatments, like chemotherapy, in order to go with the sham treatment that doesn't work. In fact, chelation, because it can reduce the amount of zinc in the body, some studies show that it could increase the potential for pre-cancerous cellular mutations, among other problems. So ironically, chelation could actually increase your chances of getting cancer.
J: Some alt-med practitioners administer EDTA, a chelating agent, to patients with atherosclerosis. This treatment for coronary artery disease has not been shown to be effective and is not approved by the FDA. Trials to assess chelation therapy were proposed and have been deeply criticized, mainly because previous controlled trials have not indicated benefits. The American Heart Association states that there is no scientific evidence to demonstrate any benefit from this form of therapy, and that the United States Food and Drug Administration, the National Institute of Health and the American College of Cardiology all agree with the American Heart Association.
S: In fact, the American College for the Advancement in Medicine, or the ACAM, is an organization founded in 1973 specifically to promote the use of chelation therapy, but also to defend physicians or practitioners who wish to use it without falling prey to regulation. It's interesting to note: this is a treatment generally given by physicians because it is an FDA approved drug, although the pseudo-science comes in using it for indications for which there's really no plausible mechanism and for which there is no evidence that it's effective. In addition to heart disease, which is the classic claim, it gets attention for other treatments as well. In recent years, chelation therapists have been using this modality to treat autism. Now, autism is a neurological disorder that is largely genetic in origin. However there is a false belief that autism is caused by mercury toxicity, whereas the evidence shows that this is not the case. Mercury toxicity does not resemble autism. However there are many practitioners now who are using chelation therapy to treat autism on the false premise that it is due to mercury toxicity. I expect that chelation therapy will be around for a while as a fringe treatment, now labeled as a quote-unquote "alternative treatment", but that just means that there isn't evidence to support these particular uses. There is ongoing research into the use of chelation therapy for specific clinical applications like heart disease, but these studies have come under criticism for being unethical, since this is an invasive procedure that is not entirely safe, and the risks of the treatment are not justified, even experimentally, given the fact that we already have quite a bit of evidence to show that it does not work. But chelation therapy stands as one of the original forms of fringe medicine that has survived over the decades despite the fact that it is not supported by scientific evidence.
S: SGU 5x5 is a companion podcast to the Skeptics' Guide to the Universe, a weekly science podcast brought to you by the New England Skeptical Society in association with skepchick.org. For more information on this and other episodes, visit our website at www.theskepticsguide.org. Music is provided by Jake Wilson.