That Takeout Coffee Cup May Be Messing With Your Hormones
February 12, 2015
Originally published in Mother Jones
A new study suggests that whole classes of BPA-free plastics—including the kind in styrofoam—release estrogenic chemicals.
Most people know that some plastics additives, such as bisphenol A (BPA), may be harmful to their health. But an upcoming study in the journal Environmental Health finds that entire classes of plastics—including the type commonly referred to as styrofoam and a type used in many baby products—may wreak havoc on your hormones regardless of what additives are in them.
The study’s authors tested 14 different BPA-free plastic resins, the raw materials used to make plastic products, and found that four of them released chemicals that mimic the female hormone estrogen. That’s not surprising. As Mother Jones reportedearlier this year, many BPA-free plastic goods—from baby bottles and sippy cups to food-storage containers—leach potentially harmful estrogenlike chemicals. But until now, it wasn’t clear what role the resins played. The new study suggests that sometimes the resins themselves are part of the problem, though additives such as dyes and antioxidants can make it worse.
In the case of polystyrene, the resin used in styrofoam and similar products, the authors tested 11 samples and consistently found estrogen seepage after exposure to intense steam or ultraviolet rays.
Styrofoam is a registered trademark of Dow. The company stresses that its product is used for crafts and building insulation rather than food and beverage containers. (“There isn’t a coffee cup, cooler, or packaging material in the world made from actual Styrofoam,” according to Dow’s website.) But generic polystyrene foam, which most people call styrofoam anyway, is ubiquitous in the food services industry, where its found in everything from meat trays to takeout containers. Polystyrene resin—which the Environmental Protection Agency has labeled a suspected carcinogen—is also used to make hard plastic items, including utensils and toothbrushes.
The study also looked at three different types of Tritan—a novel plastic marketed as a safe, estrogen-free alternative to BPA-laden polycarbonate—and found that all of them leached estrogen-like chemicals.
That’s bad news for consumers, given that hundreds of household products are made from Tritan. Below are some examples, with the caveat that not all of these finished products have been specifically tested for estrogenic effects:
- CamelBak Eddy Kid’s BPA-free water bottle
- CamelBak Relay water filtering pitcher
- Foogo by Thermos sippy cups
- Hamilton Beach Multi-Blend blender
- Nalgene BPA-free water bottles (color matters; see the chart below)
- OXO Good Grips LockTop food-storage containers
- Rubbermaid Hydration Chug bottles
- Rubbermaid carafes
- Rubbermaid Premier food-storage containers
- Thermos Under Armour water bottles
- Weil Baby bottles
- Weil Baby sippy cups
- Whole Foods bulk bins
The new paper was authored by University of California-Davis toxicologist Michael Denison, who coinvented a common cell-based test for estrogen-mimicking compounds, and by scientists from CertiChem, a commercial lab in Austin, Texas. As part of the study, researchers soaked plastics resins in a variety of common solvents and tested the chemicals that seeped out using a line of breast cancer cells (MCF-7) that proliferate in the presence of estrogen and a line of ovarian cancer cells (BG-1) that light up when exposed to the female hormone.
The 200-plus samples of Tritan resins that were tested consistently leached estrogenlike chemicals after being exposed to a type of ultraviolet ray found in sunlight (UVA) and another kind that some parents use to sterilize baby bottles (UVC). In some cases, samples that hadn’t even been exposed to UV light also seeped estrogenic compounds.
While the authors didn’t identify the specific hormone-mimicking chemical (or chemicals) that leached from the resin, they tested one Tritan component—triphenyl phosphate (TPP)—and found it was estrogenic. These findings are consistent with data collected by Tritan’s manufacturer, Tennessee-based Eastman Chemical. In 2008, the company commissioned a study that used computer modeling to predict whether various Tritan ingredients could imitate estrogens, based on their chemical structures. It found that TPP was likely to be more estrogenic than BPA. As we previously reported:
Eastman, which never disclosed these findings to its customers, later commissioned another study, this one involving breast cancer cells. Again, the initial results appeared positive for estrogenic activity. In an email to colleagues, Eastman’s senior toxicologist, James Deyo, called this an “oh shit moment.”
The company now says that additional testing has determined that Tritan is not estrogenic, and insists that there is little risk of TPP leaching from Tritan containers because it breaks down during the manufacturing process. “We have no reason to expect TPP to be present in the product as supplied by Eastman,” says Maranda Demuth, an Eastman spokeswoman.
But confidential documents the company filed with the US Food and Drug Administration list TPP as one of the “substances that may be present in food after contact with Tritan.”
Read the full story here.