Antioxidant Levels May be Linked to Autism

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Antioxidant Levels May be Linked to Autism

http://www.forbes.com/lifestyle/health/feeds/hscout/2005/04/03/hscout524907.html

 

By Serena Gordon

HealthDay Reporter

 

SUNDAY, April 3 2005 (HealthDay News) -- Could oxidative stress, a

suspected contributor to many disease processes like heart disease and

cancer, also play a role in autism?

 

University of Arkansas researchers think it may.

 

In a recent study, autistic children were found to have significantly lower

levels of an antioxidant called glutathione and its metabolic precursors.

 

" Glutathione is the major antioxidant in cells important for detoxification

and elimination of environmental toxins, and its active form is reduced in

about 80 percent of the kids with autism, " said the study's lead author, S.

Jill James. She is 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.

 

Reduced levels of antioxidants, such as glutathione, would increase the

level of oxidative stress. Oxidative stress occurs when antioxidants aren't

able to clear the body of free radicals, which can damage cells in the

brain, gastrointestinal tract and immune system.

 

" [Our findings] suggest that these kids would be more sensitive to an

environmental exposure and would be less likely to detox from heavy

metals, " said James.

 

Exposure to heavy metals, such as the mercury preservative that was

commonly used in children's vaccines until recently, has long been

suspected as a trigger for autism in genetically susceptible children. Most

research, however, has failed to confirm this link, and in 2004, the

Institute of Medicine issued a report stating that it did not believe that

vaccines contributed to the development of autism.

 

Not everyone agreed with that conclusion, however. Laura Bono, chairwoman

of the National Autism Association, and the parent of an autistic child,

believes vaccines play some sort of role in the development of autism and

said the new study's findings would seem to support a link.

 

" These are children that are more vulnerable, that don't quite detox the

way the rest of us do, " said Bono.

 

James didn't look at the vaccine question for the current study. She said

that autism is believed to have a genetic basis, but that it " takes an

environmental trigger to bring out the genetics. "

 

For this study, James and her colleagues compared blood samples of 90

autistic children to those of 45 children without the disorder, and found

that the active form of glutathione was reduced by about 80 percent in

children with autism. James also said the metabolic precursors of

glutathione were reduced.

 

" If they have lower glutathione, they would reach a toxicity earlier than

someone with higher levels, " said James. " But, it's not clear whether this

is a cause or a consequence of autism, " she added.

 

James and her team also looked at changes that occur in several genes that

could affect glutathione metabolism in blood samples from 233 autistic

children, vs. 183 children without autism. They found changes in three

genes more often in the children with autism. James said these are common

genes that don't cause autism, but they could contribute to the development

of these metabolic abnormalities.

 

James presented the study findings Saturday at the American Society for

Nutritional Sciences' scientific sessions at the Experimental Biology

conference in San Diego.

 

While this study is just a first step, she 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 aren't so sure, however.

 

" 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. "

 

In other autism research released this week, scientists from the University

of California, San Diego report that the " mirror " neurons don't function

properly in people with autism. Mirror neurons are those that activate when

you perform an action and then see someone else perform the same action, or

vice versa. These neurons have also been dubbed the " monkey-see, monkey-do "

cells.

 

" The findings provide evidence that individuals with autism have a

dysfunctional mirror neuron system, which may contribute to their

impairments -- especially those that involve comprehending and responding

appropriately to others' behavior, " one of the study's author, Lindsay

Oberman, a doctoral student at UCSD, said in a statement. The research will

be published in the journal Cognitive Brain Research.