Autism is a disorder that just inspires controversy. Maybe its because we know so little about what causes autism or maybe its because of the emotions connected with childhood problems. Either way, any debate about autism tends to become very polarized and nothing divides people more than the question of mercury, chelation and autism.
The controversy started in the early nineties when it was become apparent that mercury contamination, especially in fish, was become a significant issue. About the same time, there it was there was a growing number autistic children around. Finally someone noted that the symptoms of long-term mercury poisoning in young children is similar to the symptoms of autism.
Chelation itself is a term coined in the 1920 for a chemical process. A ligand or agent attaches itself to a metal molecule to form a chelate, a new, inert substance. The chelate can then be removed thus carrying away the molecules of metal. As a medical treatment, chelation has a long history. In World War I, chelation was used as a treatment for arsenic based poison gas. It also used for treating heavy metal poisoning such as mercury, arsenic or lead. In the UK incidences of heavy metal poising are very rare because of our strict environmental and health & safety laws. However once someone pointed the finger at mercury as a cause of autism then it was obvious that chelation would be tried as a treatment for autism.
It is with doctors interested in alternative medicine that chelation has taken off. No mainstream hospital or clinic offers it but Defeat Autism Now has a list of several hundred doctors who offer chelation. This grass roots movement in favour of autism means there is little direct scientific evidence on the effectiveness of chelation. Consequently we are left with anecdotal evidence about the treatment’s effectiveness which cannot be trusted because parents and doctors involved in the treatment both want the therapy to work. The parents are desperate for any glimmer of hope and may well notice a difference when in fact there has not been any. Doctors providing the treatment clearly believe in the treatments effectiveness so may not be as rigorous as an independent doctor. This does not mean that parents or doctors are deliberately misleading others about the success of a treatment. Strict double-blind protocols for testing medicines have been developed over the last fourty years because time and time again human nature and the subconscious desire to see the what you want to see has made a fool of even the best scientists.
It is not only autism that chelation is believed by some to treat. Since the 1960’s, heart and vascular diseases have also treated using chelation by practitioners who believe heavy metals can cause a range of diseases. Fully controlled, double-blind studies have found no benefit to chelation in these area. Lead poisoning also damages the brain and chelation has been used by mainstream medical practitioners to treat it. The results are mixed with some studies showing no cognitive improvement after treatment and others showing some improvement.
The chelation treatment is normally administered through an intravenous drip though some oral treatments exists. It is a slow process requiring regular doses of the chelation agent over weeks and months. Ethylenediaminetetraacetic acid (EDTA) is the most common chelation agent and it comes in two forms, Calcium Disodium EDTA (generically known as Endrate and Disodium EDTA (known as Versinate). In 2005 an autistic boy died during chelation because the two agents were mixed up and he as given Versinate by mistake, causing a cardiac arrest.
Whether chelation works or not is highly debatable. As a treatment it is based on the idea that mercury is the cause of autism. This in itself is far from being proven and many if not most in the medical profession do not believe mercury causes autism. If we accept the mercury is the cause then chelation is the logical treatment to remove the mercury. However there is no evidence that once the mercury is removed the autistic behaviour will be reduced. Based on the current evidence chelation has little or no benefit as a treatment.
Sources: Wikipedia – Chelation Thereapy, Generation Rescue, Quack Watch – Chelation Therapy: Unproven Claims and Unsound Theories; Declining blood lead levels and cognitive changes in moderately lead-poisoned children; Effect of Chelation Therapy on the Neuropsychological and Behavioral Development of Lead-Exposed Children After School Entry
Coverage of Chelation on the Myomancy Blog Roll