Heavy Metals and Autism, PDD and ADHD

Evidence supports the role of heavy metals in causing autism, PDD and ADHD.  These children often have biochemical impairments that put them at greater risk for damage caused by heavy metal accumulation.


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.

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 lead many leading experts to believe that MT impairment is a causative factor in autism.


Consequences of MT malfunction in a newborn:

  • Abnormal copper and zinc levels in the blood and brain
  • Impaired neuronal development, especially in the first 30 months of life, which could result in incomplete maturation of the digestive tract and brain
  • Loss of MTs ability to detoxify heavy metals including cadmium, mercury and other toxic heavy metals
  • Impaired immune function
  • Immature digestive tract

Environmental and heavy metal toxicity plays and important role in gene regulation.  Toxicity, especially heavy metal toxicity, will change which genes are turned “on” or “off”.  Many experts agree that autism is akin to a canary in a coal mine.  The rising autism rates are as a result of genetics being negatively impacted by a toxic environment.  The result, impaired development.


Can MT production be increased?

Yes. Research has shown that the genes themselves are not the problem.  Th impairment of MT proteins in children with ASD has somehow been “turned off” by other genetic and environmental factors.  By stimulating the production of MT proteins through biomedical treatment, it is possible to restore your child’s ability to naturally rid itself of accumulated heavy metals, help the digestive tract to mature, and correct the immune system impairments.

Why is restoring MT so important?

MT is directly involved in development of the brain and maturation gut and immune system.  By age three, these systems may have sufficiently matured so that environmental toxins can no longer provoke autism.

What is glutathione and why is it important?

Glutathione is the body’s cheif detoxifier.  It works with MT proteins to remove heavy metals and other harmful substances like pesticides and PCBs.

Research by Dr. S. Jill James, a professor at the University of Arkansas and Director of the Genomics Laboratory, has shown that children with ASD have low levels of glutathione.  Dr. James has just received an NIH (National Institute of Health) grant for her ground breaking research.  

How do you test for heavy metals?

There are a number of different laboratory assessments for heavy metal toxicity.  Hair, urine, stool and blood can be testing to identify metals that have been identified as causative factors 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 environment’s role in autism.  The objective the study was to determine if proximity to sources of 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 affect every aspect of our body.  Renowned medical doctor and researcher Dr. Needleman has shown the detrimental effect of lead on cognitive development.  Lead levels have been linked to autism, PDD and 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.   


You can also find more information on environmental toxicity and developmental disorders at Generation Rescue:


Environmental mercury release, special education rates, and autism disorder: an ecological study of Texas.

Palmer RF et al.
Health Place. 2006 Jun;12(2):203-9.

“On average, for each 1,000 lb of environmentally released mercury, there was a 43% increase in the rate of special education services and a 61% increase in the rate of autism.”
PMID: 16338635

Autism spectrum disorders in relation to distribution of hazardous air pollutants in the san francisco bay area

Windham GC  et al.
Environ Health Perspect. 2006 Sep;114(9):1438-44.

“The adjusted odds ratios (AORs) were elevated by 50% in the top quartile of chlorinated solvents and heavy metals [95% confidence intervals (CIs) , 1.1-2.1], but not for aromatic solvents. Adjusting for these three groups simultaneously led to decreased risks for the solvents and increased risk for metals (AORs for metals: fourth quartile = 1.7 ; 95% CI, 1.0-3.0 ; third quartile = 1.95 ; 95% CI, 1.2-3.1) . The individual compounds that contributed most to these associations included mercury, cadmium, nickel, trichloroethylene, and vinyl chloride.”
PMID: 16966102

Maternal residence near agricultural pesticide applications and autism spectrum disorders among children in the California Central Valley

Roberts EM et al.
Environ Health Perspect. 2007 Oct;115(10):1482-9.

“Multivariate a posteriori models comparing children of mothers living within 500 m of field sites with the highest nonzero quartile of organochlorine poundage to those with mothers not living near field sites suggested an odds ratio for ASD of 6.1 (95% confidence interval, 2.4-15.3). ASD risk increased with the poundage of organochlorine applied and decreased with distance from field sites.”
PMID: 17938740


Proximity to point sources of environmental mercury release as a predictor of autism prevalence

Palmer RF, Blanchard S, Wood R.
Health Place. 2008 Feb 12 [Epub ahead of print]

The objective of this study was to determine if proximity to sources of mercury pollution in 1998 were related to autism prevalence in 2002. Autism count data from the Texas Educational Agency and environmental mercury release data from the Environmental Protection Agency were used. We found that for every 1000 pounds of industrial release, there was a corresponding 2.6% increase in autism rates (p<.05) and a 3.7% increase associated with power plant emissions (P<.05). Distances to these sources were independent predictors after adjustment for relevant covariates. For every 10 miles from industrial or power plant sources, there was an associated decreased autism Incident Risk of 2.0% and 1.4%, respectively (p<.05). While design limitations preclude interpretation of individual risk, further investigations of environmental risks to child development issues are warranted.
PMID: 18353703