It's a theory.
Polycarbonate plastics are often used in containers that store food and beverages such as water bottles and baby bottles. Epoxy resins are used to coat the inside of metal products like food cans, bottle tops and water supply lines. Some dental sealants and composites may also contain BPA.
When Dr. Karp spoke at a recent Healthy Child Healthy World and Environmental Working Group luncheon, he said, "Every single one of you have BPA in your bodies just from all the exposure you have. You have phthalates, which are plastic parts, which are in every new car. Those have a hormonal effect and there are dozens of others; all different classes.
The weird thing is that hormones are signalers; they tell cells, 'Do this, don't do that,' and what can happen is these hormonally active chemicals make it into the brains of young babies, or even before birth, and shift the brain's development."
BPA mimics the hormone estrogen in the body and disrupts the endocrine system, which is dangerous for developing humans and animals.
A study also found that there's lowered ability to metabolize and eliminate BPA from the body for children who have autism.
"It has been suspected for a lot of years that BPA is involved in autism. We've shown there is a link. The metabolism of BPA is different in some children than it is in otherwise healthy children," said lead investigator Peter Stein.
The research team analyzed urine from 46 children with autism and 52 unaffected children. They evaluated how much of the BPA in each child's urine had been metabolized in a way that efficiently eliminated it. The children with autism tended to have higher amounts of unmetabolized BPA in their urine than the children without autism.
This difference was especially large when the overall levels of BPA were high. The researchers interpreted this as some evidence that the severity of autism symptoms may increase as the ability to eliminate BPA decreases, at least in some children. But there were too few participants to draw any conclusive conclusions.
"The reason I think that this [BPA] could be related to autism is because it's something that isn't split evenly between boys and girls. Boys get more autism — boys get four times more autism, they're diagnosed nine times more with Asperger's Syndrome. So it could be that if we just pushed it a little bit further, that may be the reason we're seeing this increase," Dr. Karp concluded.
BPA's replacement, BPS, may be just as dangerous, so it's a good idea to avoid both. Eat as many fresh fruits and vegetables, and choose silicone storage products, since they're BPA- and BPS-free.
In the meantime, more research is needed regarding the BPA/BPS and autism link.