Q&A: Phthalates and Child Brain Development

A consortium of scientists, health professionals, and children’s and environmental advocates recently published an article in the American Journal of Public Health identifying ortho-phthalates as neurotoxic chemicals that increase children’s risks for learning, attention, and behavioral disorders. In particular, the work demonstrates that prenatal exposures to phthalates can contribute to attention problems in children.

Phthalates have long been known to harm reproductive tract development in males, but the new article, which surveys recent mounting evidence in humans and experimental animal studies, concludes that phthalates can do lasting harm to child brain development.

The consortium behind the new article is called Project TENDR (Targeting Environmental Neuro-Developmental Risks), and its research group includes Heather Patisaul, a neuroendocrinologist and associate dean for research in NC State’s College of Sciences. The Abstract recently sat down with Patisaul to talk about the findings.

TA: What are phthalates? Where are they found?

Patisaul: They are plasticizers that are found in soft plastics like medical tubing, pet toys, some children’s toys, food containers and a ton of different building materials. They’re also used in cosmetics and personal care products, and are a common component of fragrances used in household cleaners. They’ve also been detected in the coating of some medicines. It can be hard to get a full picture of when and where they’re used because no one keeps good track of that, but they’ve been used in consumer products for decades.

TA: What drove researchers to investigate health impacts of phthalates specifically?

Patisaul: They were one of the earliest groups of chemicals found to disrupt hormone function and thus labeled “endocrine disruptors.”

TA: What are the known health impacts of phthalate exposure? Why is neurological development affected? Are there other organs or systems that can be affected?

Patisaul: They inhibit testosterone production, which can cause reproductive disorders in boys if exposed in the womb. Testosterone is needed during development to form the male reproductive organs, but also to masculinize the human male brain. Since some phthalates inhibit testosterone production, you can get genital malformations like hypospadias, or improper brain development if exposed prenatally. Less is known about specifically how they impact the developing brain, but we reached consensus that there is sufficient evidence in people and animals that they do.

TA: Are these effects irreversible?

Patisaul: Yes. If you do not build your organs correctly, particularly the brain, there is no way to correct that. Because the outcomes can be irreversible is why this and other research groups are so concerned.

TA: What level of exposure to phthalates is considered dangerous? What levels do humans typically have in their bodies?

Patisaul: Concentrations depend on the phthalate and levels vary with age and geography, but people generally have levels that are measurable in micrograms (ug) per liter (or lower) in their blood. All of us have a mixture of phthalates in our bodies at any given time, with babies having the most because they spend so much time on the floor and put things in their mouths. The good news is that evidence from the CDC and others show that as these chemicals are removed from products, human blood levels rapidly go down.

“Safe” levels determined by FDA or EPA also depend on the phthalate and focus on the whole body. They can be as low as 0.1 ug/kg body weight or as high as 100 ug/kg body weight. The phthalates of focus in the article are the ones with those really low “safe” concentrations because it’s plausible humans are exposed to that much. The others are most certainly in us, but less of a health concern so far as we know.

TA: What can we do to avoid exposure?

Patisaul: Buy fragrance-free products whenever possible, choose cosmetics produced without phthalates and other endocrine disruptors (there are tools online that can help you do that), and try to avoid plastic wrap and plastic food containers of any kind. Phthalates are so pervasive that it’s impossible to reduce exposure to zero, but proactive choices have been proven to reduce body burden.