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7 Things Hormone Researchers Want You To Know About Plastic Safety

Leftovers in plastic containers in a freezer
Kathleen Franklin via Flickr/
You might want to think twice before popping your tupperware in the microwave.

Baby aisles now stock BPA-free baby bottles, phthalate- free bath toys, and products free of polyvinyl chloride, or PVC, (which can also contain phthalates).  Researchers have linked each of these ingredients to potential harmful health impacts. But even as consumers shell out money to replace their bottles and sippy cups with BPA-free ones, now some studies suggest some of the replacement ingredients also have endocrine-disrupting effects. This can be frustrating for parents and consumers.  So we asked endocrinologists and other experts what changes they have made around their own homes to reduce their exposure. They shared these tips.

For more about the potential health effects of plastics, see Part 1 of this series: In The Debate On Plastics Safety, Policy Lags Behind Science

1. Avoid the worst offenders.

Sarah Evans, a neuroscientist at Mount Sinai’s Children's Environmental Health Center in New York City, recommends avoiding plastics with the recycling symbols 3, 6, and 7.

Number 3 is polyvinyl chloride, or PVC, which can contain phthalates, and has the added problem that a known carcinogen is produced both during its manufacture and again, if it’s ever burned with trash.  PVC is used in many children’s bath toys like rubber ducks and inflatable inner tubes.  It’s also used to make disposable plastic packaging for consumer products, and it’s in some children’s raincoats.

Number 6 is polystyrene, generally what we think of as Styrofoam, which has known estrogenic properties. Examples are the white foam cups used for holding hot coffee or tea.

Number 7 can be polycarbonate, which often contains BPA or BPA-substitutes, several of which are suspected of having similar characteristics to BPA. This type is often hard and clear plastic.  Examples are some clear reusable water bottles, some home pantry food storage containers, and the plastic parts of many popular food processors.

Mike Usey, whose company Certichem helped test more than 450 plastic products for estrogenic activity, says there are certain materials he and his colleagues have found to be almost consistently estrogenic.  These include a class of rubbery plastics called elastamers. "Silicone, latex, basically things that feel kind of rubbery … tend to be problematic," says Usey. He also warns against brightly-colored items, because many colorants can contains endocrine disruptors.

2.  Chose another material.

You've probably seen more glass, wooden, and stainless steel containers and food utensils in stores in recent years. Evans recommends choosing these alternatives over plastic ones when you can. She recommends wooden baby toys over plastic ones, too.  She says small children are at higher risk “…because they put more things in their mouths, they’re closer to the ground where a lot of chemicals settle, and many food containers for children are made of plastic.”  Since developing fetuses are perhaps the most vulnerable, she also recommends mothers-to-be avoid canned food and drink, because BPA is often present in cans’ lining.

3. Keep plastic containers cool and out of the sun.

Several scientists advise to avoid heating your plastics, whether by microwave, dishwasher, or sunlight. "The hotter the material is, the greater the leaching of any chemical would be," warns developmental endocrinologist Frederick vom Saal.

He says even if a container is labelled “microwave-safe” or “dishwasher-safe,” you’re better off keeping it away from heat. “There is no plastic on the market that should be put in heat, in the oven or the microwave, says vom Saal. “There are unknown numbers of chemicals in there. We don’t know what they are, [and] they haven’t been tested.” Ultraviolet rays can also increase the leaching of endocrine disrupting chemicals from plastics. When out and about, don’t leave your plastic bottles in direct sunlight for prolonged periods of time.   Avoid microwaving with cling wrap or leaving it in the sun, too.

Mike Usey, whose company conducted the largest and most comprehensive testing to date on estrogenic chemicals leaching from plastics, says sunlight can cause more chemical leaching than microwaving. "So if you’re out on a picnic with your baby, I would not take the baby bottle out until you’re ready to use it," says Usey. "Same thing with the water bottle.”

4. Ask manufacturers about the chemicals in their products.

If you want more information on what’s inside your plastic products,  call or write the manufacturer to find out what ‘s inside and whether the company has tested for estrogenic chemicals.

There’s no regulation requiring manufacturers to disclose the chemicals in food packaging, says Sarah Evans of the Children’s Environmental Health Center at Mt. Sinai’s Ichan School of Medicine. “There’s really no way to know what’s in your food packaging. We really encourage people to contact their legislators, push for stronger regulations that are really protective of the most vulnerable populations.  Because this is something that is really extremely difficult to shop your way out of.”

5. Get rid of dust bunnies.

Clean floors frequently to minimize dust in your home, particularly if you have a baby or toddler crawling or playing close to the floor.   “Endocrine disruptors can come in many forms and are in many things that we use or ingest in a day,” says Suzanne Fenton, who leads the Reproductive Endocrinology Group in the National Toxicology Program at the National Institute of Environmental Health Sciences.  The dust on our floors contains molecules of endocrine disruptors from things we use all day, from household electronics and computer casings to plastic food packaging.

6. Shop local (and package-free).

Our diets are a big source of exposure to endocrine disruptors. Buy fresh foods from local suppliers “that hasn’t been wrapped and shipped all over the country in packaging you’re not familiar with,” suggests Evans.

7. Coming Soon: Look up your plastics.

The non-profit Environmental Working Group has a database where you can look up how your cosmetics and personal care products rank in terms of potential health risks of in their ingredients. Usey hopes to launch a similar searchable database for plastics.  He’s aiming to have it online by late summer 2015. 

Learn more:

EWG’s guide:  Pick Plastics Carefully

The Endcorine Society’s Introduction to Endocrine Disrupting Chemicals

Environmental Working Group’s Skin Deep database

Breast’s Tips to Reduce Your Risk