Sunday, April 03, 2005

New study sheds light on mercury/autism connection

Posted by Craig Westover | 11:46 PM |  

It’s one of those cut and paste stories on page 17A of Sunday’s Pioneer Press. A pick up from the Los Angeles Times. Six-and-a-half column inches. “Study: Autistic children lack antioxidant.” The story with more detail is found here and here.

The study by researchers at the University of Arkansas for Medical Sciences in Little Rock found that a single breakdown in the body's ability to produce the antioxidant gluthathione might underlie many of the symptoms of autism. (The research was presented at the Experimental Biology 2005 conference in San Diego. A copy can be found here.)

Cut from the Pioneer Press version of the Los Angeles Times article is this paragraph --

The finding is suggestive, several experts said, because glutathione also is crucial for neutralizing toxic heavy metals such as mercury, which is found in food, the air and, at one time, a vaccine preservative called thimerosal.
This is indeed an unkind cut because currently legislation that would significantly curtail the use of vaccines containing mercury, specifically the preservative thimerosal, is working its way through the Minnesota House and Senate.

By identifying that a lack of gluthathione is common to nearly all autistic children, this study significantly strengthens the contention of the legislation supporters that mercury could cause or contribute to autism and other neurodevelopmental disorders by reducing the ability of certain children to mount a defense against neurotoxic compounds, which includes mercury.

Anti-oxidants like gluthathione are part of the body’s natural defenses against free oxygen radicals -- corrosive molecules in the body that can severely damage developing brain cells. Glutathione also is the body's most important tool for detoxifying and excreting metals.
The active form of gluthathione is reduced in about 80 percent of the kids with autism," said the study's lead author, S. Jill James, director of the biochemical genetics laboratory at Arkansas Children's Hospital Research Institute and a professor of pediatrics at the College of Medicine at the University of Arkansas for Medical Sciences in Little Rock.

"[Our findings] suggest that these kids [children with autism] would be more sensitive to an environmental exposure and would be less likely to detox from heavy metals," James is quoted in a HealthDay News report. In other words, they would not excrete heavy metals, which would then infiltrate and cause organ damage including neuron damage in the brain.

Although James et. al. did not look at the vaccine question as part of the current study, their work lends significant credence to the scientific support for a link between autism and autism-like symptoms and the mercury-based preservative thimerosal that was used extensively in childhood vaccines until recently (and is still found in some childhood vaccinations and flu shots).
The study suggests that range in severity of autism is because maturing neurons and synapses are especially vulnerable to this biomolecular bombardment. Autism could therefore cause different symptoms and severity in children depending on when the disorder is triggered.

One wonders how public health officials will respond to this study.

On one hand, the study supports the theory that autism has a genetic cause. But to stop scientific investigation there, as one public health professional is wont to do, is to use science the way a drunk uses a light post -- for support not for illumination. The healthcare establishment has consistently denied (but never conclusively refuted with scientific evidence) that there is no link between mercury found in vaccines and autism.

Nonetheless, given new perspective provided by the James et. al. study, the correlation between increased incidence of autism (from a 1980 level of four to five cases for every 10,000 live births to the current CDC estimate of one case in every 166 live births) and the significant increase in the number of vaccinations children receive (read more shots, each with a dose of mercury preservative) between birth and 18 months of age (when both the immune system and brain functions are still developing) bears further investigation.

There are significant implications of the study for public health officials.

This study identifies a subgroup of people at increased risk of harm, and provides important new evidence that policies designed to protect the average person, or the average child, from mercury exposure, are insufficient to fully protect the public health.

The challenge for Minnesota legislators is evaluating our state’s current laws and policies to determine if they protect individuals with a genetic inability to process and excrete mercury. The proposed legislation provides that protection.

Further, the James et. al. study should give pause to public health officials using epidemiological studies, such as those from Denmark cited in a recent Pioneer Press Op-Ed piece, to make the case for vaccine safety. The epidemiologic studies used to dismiss a causal relationship between autism and thimerosal assume that all children have the same resistance to mercury exposure. To properly investigate the potential harm from mercury-containing shots researchers would have to compare autism rates in children with the same type of vulnerability.

Whether or not such research will be publicly pursued is a matter of conjecture. But a good indication might be these comments and case study.

While noting that this study is just a first step, James said, it wouldn't be unreasonable for parents of autistic children to talk with their child's doctor about giving them antioxidant supplements since these supplements are non-toxic.

Others from the medical establishment aren't so sure.

"This is an interesting study and worth some more follow-up, but for parents or clinicians, it's an item of note, not a call to action," said Craig Newschaffer, director of the Center for Autism and Developmental Disabilities Epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore. "There are no leaps to be made about using antioxidants as a therapeutic agent."

For another perspective, this case study is an interesting read.