Elevated heavy metals linked to Autism

Exposure to the heavy metals is linked to autism and other developmental delays.  Heavy metals such as mercury and lead negatively impact language, behavioral regulation and cognitive function in autism.

Is there any research directly linking heavy metals to autism?

A ground breaking study in 2009, done by researchers at the University of Texas, revealed startling evidence of the role of heavy metals and other environmental toxins in autism. The objective the study was to determine if proximity to sources of the heavy metals, such as mercury pollution in 1998 were related to autism prevalence in 2002. The findings showed that for every 1000 pounds of industrial release, there were a corresponding 2.6% increase in autism rates and a 3.7% increase associated with power plant emissions. For every 10 miles from industrial or power plant sources, there a decrease in autism rates.

An earlier study released by the same group of investigators revealed an association between environmentally released mercury and autism rates in Texas.  For each 1,000 lb of environmentally released mercury, there was a 61% increase in ASD. The same study showed an increase of 43% in the rate of special education rates.

Toxins and human health:
Toxins affect every aspect of our body. Renowned medical doctor and researcher Dr. Needleman has shown the detrimental effect of lead on cognitive development. Elevated lead levels increase rates of autism, ADHD and learning disabilities.

A study by the Environmental Working Group (EWG) in found an average of 200 industrial chemicals and pollutants in umbilical cord blood from 10 babies born in U.S. hospitals in 2004.  Tests revealed a total of 287 chemicals in this small group of children. The umbilical cord blood collected by Red Cross after the cord was cut, identified pesticides, consumer product ingredients, and wastes from burning coal, gasoline, and garbage.

Heavy metals can impact brain development, but also can cause changes in the methylation pathways.

Elimination of toxins:
Important systems in treatment of heavy metal detoxification are consideration of glutathione detoxification pathway, support for the metallothionein system, and proper function of the digestive system. Metals sequestered inside tissues have to be moved into metallothionein units which are then moved to the liver for detoxification in the glutathione conjugation pathway and then prompt removal from the body by the digestive system. 

How is the heavy metal transported?

Metallothioneins (MTs) are part of a group of intracellular cysteine-rich, metal-binding proteins that have been found in bacteria, plants, invertebrates and vertebrates. For mammals, metallothioneins bind zinc, but with excess copper or cadmium, zinc can be easily replaced by these metals. MTs have the capacity to bind both physiological (such as zinc, copper, selenium) and xenobiotic (such as      cadmium, mercury, silver, arsenic) heavy metals like mercury and aluminum through the thiol group of its cysteine residues.

The research of Dr. William Walsh, Ph.D, and Dr. Anjum Usman, MD, have found alterations in the functioning of metallothionein protein (MT) in children with autism. This impairment impacts brain development and causes extreme sensitivity to toxic metals and other environmental substances. This supports and begins to explain why environmental toxicity combined with genetic susceptibility leads to autism.

MT research in autism:
In a study of 503 autistic patients, Dr. Walsh and Usman found abnormal levels of copper and zinc in blood. This indicates defective functioning of MT proteins. These MT proteins regulate blood levels of these trace minerals, detoxify mercury and other heavy metals, and assist in development of the nervous system. Consequences of defective MT during pregnancy or early infancy are consistent with several classic symptoms of autism. This has led many leading experts to believe that MT impairment is a causative factor in autism.