Despite speculation that children that suffer from autism have higher mercury levels in their blood, it has recently been discovered that children with autism have mercury levels that are very similar to those of non-autistic children, suggesting that the mysterious disorder is cause by a range of factors rather than just “a single smoking gun,” said researchers.
The research team at the University of California, Davis initially found that children between the ages of 2 and 5 with autism had mercury levels that were lower than other children because they ate less fish, which is the biggest source of mercury that shows up in our blood. However, when the data was adjusted for the lower fish consumption, the blood-mercury concentrations amount the autistic children were roughly similar to those children that were developing normally. The children with autism also had mercury levels that were in line with national norms.
The research findings, which were published online in the journal Environmental Health Perspectives, comes at a time when advocates, including the parents of autistic children, argue that the mercury found in fish, vaccines, dental fillings and industrial emissions are responsible for autism. This debate became more vehement this month after the U.S. Centers for Disease Control and Prevention stated that autism was more common than they previously thought, affecting approximately one in 91 children, including approximately one in 58 boys.
Irva Hertz-Picciotto, the researcher who led the study, said, “It’s time to abandon the idea that a single smoking gun will emerge to explain why so many children are developing autism. Just as autism is complex, with great variation in severity and presentation, it is highly likely that its causes will be found to be equally complex.”
Autism refers to a broad spectrum of diseases, from severe and profound inability to communicate and mental retardation to symptoms that are relatively mild. The research area of autism is due a large infusion of money from President Barack Obama’s $5 billion plan to boost U.S. scientific and medical research.
The activists also noted that the University of California study did not seem to find out whether the mercury levels might cause autism because the children’s blood levels were measured after the children had been diagnosed with the disorder. Sallie Bernard, who is the executive director of the advocacy group SafeMinds, said, “The results of this study are limited in terms of ruling in or out a link between mercury exposure and autism causation or severity.”
The vaccines with the mercury-containing preservative called thimerosol have also been blamed, by some of the parents, as a potential cause of autism, although many studies and several reports from the Institute of Medicine have still not found a link.