Study: No link between mercury exposure and autism-like behaviors

Keep sharp objects away from RFK Jr. and Jenny McCarthy.

The media release is below.


Study: No link between mercury exposure and autism-like behaviors

The potential impact of exposure to low levels of mercury on the developing brain – specifically by women consuming fish during pregnancy – has long been the source of concern and some have argued that the chemical may be responsible for behavioral disorders such as autism. However, a new study that draws upon more than 30 years of research in the Republic of Seychelles reports that there is no association between pre-natal mercury exposure and autism-like behaviors.

“This study shows no evidence of a correlation between low level mercury exposure and autism spectrum-like behaviors among children whose mothers ate, on average, up to 12 meals of fish each week during pregnancy,” said Edwin van Wijngaarden, Ph.D., an associate professor in the University of Rochester Medical Center’s (URMC) Department of Public Health Sciences and lead author of the study which appears online today in the journal Epidemiology. “These findings contribute to the growing body of literature that suggest that exposure to the chemical does not play an important role in the onset of these behaviors.”

The debate over fish consumption has long created a dilemma for expecting mothers and physicians. Fish are high in beneficial nutrients such as, selenium, vitamin E, lean protein, and omega-3 fatty acids; the latter are essential to brain development. At the same time, exposure to high levels of mercury has been shown to lead to developmental problems, leading to the claim that mothers are exposing their unborn children to serious neurological impairment by eating fish during pregnancy. Despite the fact that the developmental consequences of low level exposure remain unknown, some organizations, including the U.S. Food and Drug Administration, have recommended that pregnant women limit their consumption of fish.

The presence of mercury in the environment is widespread and originates from both natural sources such as volcanoes and as a byproduct of coal-fired plants that emit the chemical. Much of this mercury ends up being deposited in the world’s oceans where it makes its way into the food chain and eventually into fish. While the levels of mercury found in individual fish are generally low, concerns have been raised about the cumulative effects of a frequent diet of fish.

The Republic of Seychelles has proven to be the ideal location to examine the potential health impact of persistent low level mercury exposure. With a population of 87,000 people spread across an archipelago of islands in the Indian Ocean, fishing is a both an important industry and a primary source of nutrition – the nation’s residents consume fish at a rate 10 times greater than the populations of the U.S. and Europe.

The Seychelles Child Development Study – a partnership between URMC, the Seychelles Ministries of Health and Education, and the University of Ulster in Ireland – was created in the mid-1980s to specifically study the impact of fish consumption and mercury exposure on childhood development. The program is one of the largest ongoing epidemiologic studies of its kind.

“The Seychelles study was designed to follow a population over a very long period of time and focus on relevant mercury exposure,” said Philip Davidson, Ph.D., principal investigator of the Seychelles Child Development Study and professor emeritus in Pediatrics at URMC. “While the amount of fish consumed in the Seychelles is significantly higher than other countries in the industrialized world, it is still considered low level exposure.”

The autism study involved 1,784 children, adolescents, and young adults and their mothers. The researchers were first able to determine the level of prenatal mercury exposure by analyzing hair samples that had been collected from the mothers around the time of birth, a test which can approximate mercury levels found in the rest of the body including the growing fetus.

The researchers then used two questionnaires to determine whether or not the study participants were exhibiting autism spectrum-like behaviors. The Social Communication Questionnaire was completed by the children’s parents and the Social Responsiveness Scale was completed by their teachers. These tests – which include questions on language skills, social communication, and repetitive behaviors – do not provide a definitive diagnosis, but they are widely used in the U.S. as an initial screening tool and may suggest the need for additional evaluation.

The mercury levels of the mothers were then matched with the test scores of their children and the researchers found that there was no correlation between prenatal exposure and evidence of autism-spectrum-like behaviors. This is similar to the result of previous studies of the nation’s children which have measured language skills and intelligence, amongst other outcomes, and have not observed any adverse developmental effects.

The study lends further evidence to an emerging belief that the “good” may outweigh the possible “bad” when it comes to fish consumption during pregnancy. Specifically, if mercury does adversely influence child development at these levels of exposure then the benefits of the nutrients found in the fish may counteract or perhaps even supersede the potential negative effects of the mercury.

“This study shows no consistent association in children with mothers with mercury level that were six to ten times higher than those found in the U.S. and Europe,” said Davidson. “This is a sentinel population and if it does not exist here than it probably does not exist.”

“NIEHS has been a major supporter of research looking into the human health risks associated with mercury exposure,” said Cindy Lawler, Ph.D., acting branch chief at the National Institute of Environmental Health Sciences, part of National Institutes of Health. “The studies conducted in the Seychelles Islands have provided a unique opportunity to better understand the relationship between environmental factors, such as mercury, and the role they may play in the development of diseases like autism. Although more research is needed, this study does present some good news for parents.”


3 thoughts on “Study: No link between mercury exposure and autism-like behaviors”

  1. the scientific community allways blame something if they dont know the answer but fish give a break.

  2. People are generally waking up to the fact that pharmaceutical companies have no interest in cures, only in producing medication which ‘controls’ and requires repeat perscriptions. These are companies required by law to maximise profits for their shareholders.

    Specifically, the many ‘epidemic’ MSM scares requiring mass innoculation at great cost, such as ‘bird flu’, have been shown to be irrational – which even the general public not looking into the detail of the pharmaceutical companies’ involvement have correctly judged to be a scam – and more worryingly the addition of mercury to vaccinations, which fact is becoming better known, have resulted in many refusing to vaccinate, themselves and their children.

    It fail to see anything illogical in this.

    Why should anyone trust pharmaceutical companies? Would you continue going to a doctor who has been shown to be incompetent?

    Some background on the mercury aspect:

    It should be noted in this report in the comparison with levels found in fish, that fish contain high levels of selenium a natural antidote to mercury toxicity.

    Some background on why mercury was first used and why banned:

    And this is a must read –

    “Published on Thursday, June 16, 2005 by
    Deadly Immunity
    When a study revealed that mercury in childhood vaccines may have caused autism in thousands of kids, the government rushed to conceal the data — and to prevent parents from suing drug companies for their role in the epidemic.

    by Robert F. Kennedy Jr.

    “In June 2000, a group of top government scientists and health officials gathered for a meeting at the isolated Simpsonwood conference center in Norcross, Ga. Convened by the Centers for Disease Control and Prevention, the meeting was held at this Methodist retreat center, nestled in wooded farmland next to the Chattahoochee River, to ensure complete secrecy. The agency had issued no public announcement of the session — only private invitations to 52 attendees. There were high-level officials from the CDC and the Food and Drug Administration, the top vaccine specialist from the World Health Organization in Geneva, and representatives of every major vaccine manufacturer, including GlaxoSmithKline, Merck, Wyeth and Aventis Pasteur. All of the scientific data under discussion, CDC officials repeatedly reminded the participants, was strictly “embargoed.” There would be no making photocopies of documents, no taking papers with them when they left.

    “The federal officials and industry representatives had assembled to discuss a disturbing new study that raised alarming questions about the safety of a host of common childhood vaccines administered to infants and young children. According to a CDC epidemiologist named Tom Verstraeten, who had analyzed the agency’s massive database containing the medical records of 100,000 children, a mercury-based preservative in the vaccines — thimerosal — appeared to be responsible for a dramatic increase in autism and a host of other neurological disorders among children. “I was actually stunned by what I saw,” Verstraeten told those assembled at Simpsonwood, citing the staggering number of earlier studies that indicate a link between thimerosal and speech delays, attention-deficit disorder, hyperactivity and autism. Since 1991, when the CDC and the FDA had recommended that three additional vaccines laced with the preservative be given to extremely young infants — in one case, within hours of birth — the estimated number of cases of autism had increased fifteenfold, from one in every 2,500 children to one in 166 children. ”

    “But instead of taking immediate steps to alert the public and rid the vaccine supply of thimerosal, the officials and executives at Simpsonwood spent most of the next two days discussing how to cover up the damaging data. According to transcripts obtained under the Freedom of Information Act, many at the meeting were concerned about how the damaging revelations about thimerosal would affect the vaccine industry’s bottom line.”

    And more links to other studies here:

  3. I’m sure the EPA has secret studies that refute this. After all, they couldn’t promulgate health-based regulations without data, could they?

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