Mercury Poisoning and Autism

Autism: A Novel Form of Mercury Poisoning

In 2000, SafeMinds founders presented and published a research effort that aided in propelling this issue into the awareness of the public and government officials. That endeavour, Autism: A Novel Form of Mercury Poisoning (Bernard, Enayati, Redwood, Roger, Binstock) was and remains recognized as a cornerstone document to the discourse on medical mercury exposure and toxicity and its effects on health. In the study, Bernard et al compiled bodies of data, including that of various US government agencies, from several facets of the issue and mapped the path between thimerosal (a widely utilized mercury laden preservative often found in vaccines) and neurological development disorders, including autism.

Autistic spectrum disorder (ASD) is a neurodevelopmental syndrome with onset typically prior to age 36 months. Diagnostic criteria consist of impairments in sociality and communication plus repetitive and stereotypic behaviors and stereotypic behaviors. Traits strongly associated with autism include movement disorders and sensory dysfunctions. Although autism may be apparent soon after birth, most autistic children today experience at least several months, even a year or more of normal development – followed by regression, defined as loss of function or failure to progress.

In the 2000 report, SafeMinds recounted the history of events illuminating the neurotoxicity of mercury (Hg):

  • Mercury-contaminated fish in Japan - Minimata Disease
  • Mercury-tainted grain in Iraq, Guatemala and Russia
  • Acrodynia (also called Pink Disease) induced by mercury in teething powders
  • Numerous instances of mercury poisoning through occupational exposures – Mad Hatter’s disease
  • Numerous animal and in vitro studies providing insights into the mechanisms of mercury toxicity.

The history of acrodynia, a severe disorder caused by low doses of mercury in teething powder, is particularly enlightening. When mercury-based teething powder was banned in the early 1950’s, acrodynia cases ceased. It is important to note that only a small but significant percentage of children who used the teething powders were afflicted with acrodynia, indicating that there is perhaps a small portion of children that is particularly susceptible to mercury toxicity. Interestingly, research indicates that children with autism are far more susceptible to mercury poisoning that the general population, likely due to an inability to adequately excrete toxins.

Based on the admission by the US Food and Drug Administration (FDA) that thimerosal, a product that had been banned as an Over-the-Counter product, was still in use as a vaccine preservative; and that infants were exposed to levels of mercury in excess of federal safety guidelines, SafeMinds looked at the possible consequences to this exposure. The FDA’s announcement coupled with a significant number of parents reporting the onset of symptoms shortly after immunization and the direct correlation in the increased prevalence of ASD and the increased exposure to infants to thimerosal through immunizations, highlighted the need to review the science in both areas to determine if acquired autism was a novel form of mercury poisoning. (Acquired autism is also sometimes called regressive autism. It is this form of autism that has become more prevalent in the last 15 years.)

ASD manifests a constellation of symptoms with much inter-individual variation. A comparison of traits defining, nearly universal to, or commonly found in autism with those known to arise from mercury poisoning are startlingly similar.

Summary Comparison of Traits of Autism and Mercury Poisoning
Summary of Comparison of Biological Abnormalities in Autism and Mercury

Environmental Mercury Exposure and the Risk of Autism:

In recent years, there has been a growing focus on the risk of autism from environmental mercury exposure. The 2008 SafeMinds white paper, Environmental Mercury Exposure and the Risk of Autism, provides a detailed description of how environmental mercury exposure could contribute to autism. The paper describes the various types of mercury and sources of environmental mercury exposure. Estimated exposure levels are compared to recommended limits of mercury exposure. The paper includes a description of how flora (e.g. bacteria) in the gastrointestinal tract could play a role in mercury excretion. The effect of Mercury on cellular toxicity and oxidative stress are described. The Environmental Mercury Exposure and the Risk of Autism white paper provides an overview of the mechanisms by which mercury can cause disease. Of particular note, the paper provides information on the mercury accumulation in the endocrine system and potential links between mercury and endocrine dysfunction.

In March 2009, researchers led by Dr. Shirlee Tan of the EPA published The Endocrine Effects of Mercury in Humans and Wildlife, which summarized the existing literature on the effects of mercury on the endocrine system and identifies gaps in the knowledge. The paper focused on the thyroid, adrenal, and reproductive systems, including the accumulation of Hg in the endocrine system. The paper identified five main endocrine-related mechanisms of Hg across the thyroid, adrenal, and reproductive systems, and recommended key areas of research. The effect of mercury on the endocrine system is under-studied, and SafeMinds plans to advocate for further focus on this area of research.