Doctor explores link between toxic chemicals and autism

One of America’s leading pediatricians is asking whether hormone-disrupting chemicals like bisphenol A, phthalates and flame retardants are to blame for the rising tide of autism.

Harvey Karp, M.D., best-selling author of The Happiest Baby on the Block and an assistant professor of pediatrics at UCLA, makes the connection in a Huffington Post article titled Cracking the Autism Riddle: Toxic Chemicals, A Serious Suspect in the Autism Outbreak.

Karp says we must look at the link between the rise of toxic chemicals in the products that surround us, including everything from water bottles and cosmetics to toys and couches, and the corresponding rise in autism.

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.

How is human exposure to these chemicals linked to autism? Karp points out that women of childbearing age are contaminated with these hormone-disrupting chemicals, as is the rest of the population, and that these chemicals are known to cross into the fetus, threatening to alter a baby’s brain during what scientists call developmental “windows of vulnerability.”

A growing theory about autism’s genesis goes back to brain development in the womb. It is possible, Karp argues, that exposure to these toxic chemicals while in the womb affects the delicate balance of hormones and alters the baby’s brain.

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).

While the connection between hormone-disrupting chemicals and autism is still just a theory, Karp endorses massive federal investments both in studying children to look for clues to the cause of autism and in doing more to understand and regulate these toxic chemicals.