THE BLOG
02/02/2010 03:42 pm ET | Updated Nov 17, 2011

Cracking the Autism Riddle: Toxic Chemicals, A Serious Suspect in the Autism Outbreak

Over the past 30 years, toxic chemicals, like Teflon, plastics, and formaldehyde have increasingly invaded our homes. We used to think these substances were harmless, but a rising tide of evidence has turned the spotlight on chemical exposures as a possible poison to our children's developing brains.

One group of substances of particular concern is a ubiquitous family of hormone twisting compounds, known as endocrine disrupting chemicals (EDCs). These substances are the focus of intense scrutiny because: 1) they're found in every home in America 2) they're increasingly linked to human disease 3) our exposure to them has risen in parallel with the surge in autism diagnoses and 4) they may theoretically affect the developing fetal brain.

In recent years, research has mounted against a virtual police lineup of EDCs, like BPA (in food cans, hard plastic water bottles), phthlates (in soft plastics, cosmetics) and fire retardants (in sofas, computers, flame-resistant clothing). Multiple animal and human studies have linked EDC exposure (during or after fetal development) with a host of hormone-related disorders, like low sperm count, cancer (breast, ovarian, prostate, testicular), congenital malformation of the genitals and even obesity.

In 1996, pediatricians and other concerned scientists convinced Congress to order the Environmental Protection Agency (EPA) to test hundreds of chemicals for endocrine disrupting effects. The Clinton administration began the process of designing these tests, but the Bush administration defied the law. It ignored this mandate to protect the public health...and organized medicine watched impotently from the sidelines. Today, ten years and tens of millions of dollars later, not a single chemical has been evaluated for endocrine disrupting effects!

Our exposure to EDCs is no mere theoretical concern. In 2000, a Centers for Disease Control (CDC) study found detectable phthalates in 99.9% of adults including women of childbearing age. The CDC also discovered detectable levels of BPA in 93% of thousands of Americans tested (6 years of age and older).

The presence of EDCs in women of child-bearing age is especially worrisome. That is because there is evidence that even minuscule amounts of these chemicals -- levels commonly present in a woman's body -- may disturb fetal brain development during highly sensitive periods of neural development known as windows of vulnerability.

The US National Toxicology Program has stated that it is concerned about the "effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A."

Furthermore, since multiple different EDCs have the same effect on the developing body, exposure to a variety of EDCs may create a large cumulative stress to the body. (In the CDC study quoted above, 84% of adults tested had more than 6 different phthalates coursing through their bodies...and that study didn't even test for the presence of other EDC, e.g. pesticides, fire retardants, etc.)

Are Children with Autism..."Male-adjusted"?

Our increasing exposure to EDCs lends support to a new hypothesis about the cause of autism, called the "extreme male theory." This theory, proposed by Dr. Simon Baron-Cohen and colleagues, speculates that autism is caused by something changing a fetus' hormonal balance that then leads to over-masculinization of the developing brain.

Could that "something" be the slurry of hormone-altering chemicals we're exposed to every day? Are EDCs the reason autism-type disorders are 4-9 times more common in boys? (Vaccine side effects never show such lopsided impact on boys versus girls...a glaring fact that is totally ignored by those promoting the vaccine theory of autism.)

The "extreme male theory" has been supported by two interesting bits of evidence: 1) fetuses with slightly elevated levels of testosterone grow up acting extra-male (more interested in things than people, slow language development, etc.); 2) children with autism -- boys and girls -- show extra-male characteristics (e.g. poor social ability, language delay).

Here is where the very interesting link to EDCs comes into play: EDCs often act as weak estrogens and estrogen feminizines the body, but in a fetus' developing brain estrogen actually has the opposite effect...it causes masculinization.

For now, these ideas are just interesting theories, but the evidence is concerning. We urgently need more research to discover whether EDCs, or other chemicals, are linked to the worldwide rise in autism. Fortunately, on that front, there is very good news to report. Thanks to a dedicated group of pediatricians -- members of groups like the AAP and CDC -- the National Children's Study (NCS) was launched in January 2009.

Originally designed during the Clinton presidency, the NCS survived 8 years of Bush administration attempts to defund and demolish it. But today, the new administration has committed over $3 billion to carrying it out.

The NCS will establish over one hundred study centers across the US to test the blood of 100,000 newborns for scores of synthetic chemicals, including many EDCs. (Workers have already begun going door-to-door enrolling pregnant moms into the program.) For the next 21 years, scientists will carefully follow the children's health, comparing the body burden of chemicals at birth to diseases developed later in life.

The NCS may be our generation's best chance to solve the autism riddle. It is exactly the type of study needed to tease out the subtle relationships that may exist between autism and chemicals.

Fortunately, it won't take 21 years to start getting answers. Within 3-4 years, we expect to have enough data accumulated to start detecting what chemicals might be linked to autism. The NCS will also search for correlations between chemical exposures and other increasingly frequent serious illnesses, such as, diabetes, leukemia, brain tumors, prostate/breast/ovarian cancer, lymphoma, congenital malformations, infertility, attention deficit disorder...perhaps even Parkinson's disease.

Beside the NCS, I support other new studies to look at: 1) the autism risk in vaccinated vs. unvaccinated kids; 2) the metabolism of vaccine ingredients (like aluminum, added to make shots work better), 3) more accurate determinations of the true incidence of autism. (The number of kids getting autism is unclear. Some studies suggest that much of the autism spike is just a labeling shift: kids who used to be labeled "mentally retarded" increasingly are being labeled as "autistic.")

In conclusion, I thank all parents for their concern and interest and I especially want to salute activist parents for standing up and making their voices heard on behalf of their children...and all of our children.

Parents have the immensely important duty to nurture and raise their young children. Mastering scores of scientific studies and arguing science with biochemists or toxicologists is a great challenge that should not also be their responsibility. It's unfortunate that our nation's insufficient response to the autism surge has forced so many parents into this position. But, now is the time for all of us to join together to solve this very serious burden on our families, our economy and our collective future.

In case you missed the first two parts in this series, here are links to Part 1: Vaccines and Autism: A Proven Trigger or A Terrible Coincidence and Part 2: Good Common Sense About Vaccines and Autism.

Dr. Harvey Karp is a world renowned child development expert and America's most read pediatrician. Creator of the bestselling DVDs and books, The Happiest Baby on the Block and The Happiest Toddler on the Block, his work has literally revolutionized our understanding of the needs of young children.

The Happiest Baby teaches how parents can calm even the fussiest babies in minutes...or less...and help any baby sleep an extra one to three hours per night. The Happiest Toddler teaches a new way to communicate with children eight months to five years of age that can quickly prevent 50-90 percent of tantrums and boost a toddler's patience and cooperation in just days!

Dr. Karp’s work is taught in hundreds of hospitals, clinics and military bases across the US and has been featured times on shows like Dr. Phil, Larry King Live, The View and Good Morning ... no wonder the NY Times celebrated his work by proclaiming "Roll over Dr. Spock!"

For more information about Dr. Karp and his work, please visit: www.happiestbaby.com or follow him on facebook

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The Happiest Toddler On the Block