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Styrofoam Cups -- Clouds In Your Coffee?

Mark Jeantheau -- Styrofoam food containers, styrene migration, and your health.

It was big news years ago when McDonalds moved its sandwiches out of their trademark Styrofoam clamshells and into paper wrappers. The environment was proclaimed the winner and we all went back to saying, "Yes, I'll have fries with that."

But Styrofoam -- or more properly, polystyrene -- did not go away. Today it is still going strong in both food and non-food applications. Below are examples.

Food Applications of Polystyrene

-- coffee cups
-- soup bowls and salad boxes
-- foam egg cartons; produce & meat trays
-- disposable utensils

Non-Food Applications of Polystyrene

-- packing "peanuts"
-- foam inserts that cushion new appliances and electronics
-- television and computer cabinets
-- compact disc "jewel boxes" and audiocassette cases

In a future article we will debate the advantages and disadvantages of polystyrene's overall use -- i.e. the story of "Styrofoam and the Environment" -- but today we will take a look at the implications of using polystyrene in food and beverage applications.

Most importantly, we will talk about how styrene -- the single-molecule form of polystyrene -- migrates into your food and beverages from polystyrene food containers.

Just in case you are tempted to think this problem does not apply to you -- perhaps because styrene exposure has not caused you to grow a third ear or something -- think again. A US EPA study of fat biopsies from human subjects found styrene residues in 100% of the samples tested.

Styrene migration from styrofoam cups & containers

The migration of styrene from a polystyrene cup containing cold or hot beverages has been observed to be as high as 0.025% for a single use. That may seem like a rather low number, until you work it this way: If you drink water, tea, or coffee from polystyrene cups four times a day for three years, you may have consumed about one Styrofoam cup-worth of styrene along with your beverages. Mmm.... chemically...

Styrene migration has been shown to be partially dependent on the fat content of the food in the polystyrene container -- the higher the fat content, the higher the migration into the food. Entrees, soups, or beverages that are higher in fat (like a bowl of three-cheese chili or a cup of Triple-Cream Frappa-Mocha Java Delight) will suck more of the styrene out of the polystyrene container.

Some compounds found in beverages, like alcohol or the acids in "tea with lemon," can also raise the styrene migration rate. When it comes to more solid food, the meat or cheese you buy from the market on a clear-plastic-wrapped polystyrene tray is readily picking up styrene from the foam container. Studies have also found that styrene tends to migrate more quickly when foods or drinks are hot.

Health effects of styrene

Once styrene gets into your food or drink -- and then into you -- what does it do? Studies suggest that styrene mimics estrogen in the body and can therefore disrupt normal hormone functions, possibly contributing to thyroid problems, menstrual irregularities, and other hormone-related problems, as well as breast cancer and prostate cancer. The estrogenicity of styrene is thought to be comparable to that of Bisphenol A, another potent estrogen mimic from the world of plastics.

The official word on Styrene and cancer

Styrene is considered a possible human carcinogen by the World Health Organization's International Agency for Research on Cancer.

Long-term exposure to small quantities of styrene is also suspected of causing:

-- low platelet counts or hemoglobin values;
-- chromosomal and lymphatic abnormalities;
-- neurotoxic effects due to accumulation of styrene in the tissues of the brain, spinal cord, and peripheral nerves, resulting in fatigue, nervousness, difficulty sleeping, and other acute or chronic health problems associated with the nervous system.

Because many of these effects can be more pronounced on developing bodies, extra caution is advisable for women who are pregnant (or considering becoming so) and for prepubescent children.

Recommendations on styrofoam cups and polystyrene

There have not yet been enough studies to know whether the relatively small amounts of styrene from polystyrene (Styrofoam) cups and food containers are enough to cause health effects. But we know from studies of other chemicals that long-term, constant exposure to small amounts of foreign substances -- especially those that mimic hormones -- causes problems. So, it makes sense to avoid polystyrene as much as possible.

A Ceramic Mugging

Always using a ceramic mug instead of a Styrofoam cup is highly advisable, and mugs with lead-free components are preferable. If you use a "regular" mug, watch for breaks in the inner ceramic surface that might expose your beverage to the lead. If chips or scratches show up, pitch the mug.

Our recommendations are:

1. Use ceramic plates, bowls, and mugs/cups whenever possible. If you can't do that, choose paper over polystyrene.

2. Item 1 applies especially if your food or beverage…

-- will be hot (or get heated up in the container)
-- contains alcohol or acidic substances, or
-- has medium or high fat content.

3. Supermarket items that come sitting on or in a polystyrene food container should be removed and stored in something else until you're ready to cook or eat the items. Glass, ceramic, or porcelain containers, bowls or plates are preferable for food storage (so you don't get chemicals from plastic storage containers).

If you can choose food products that don't come in polystyrene containers in the first place, so much the better. (And remember that most restaurant "doggie bags" are really polystyrene food containers.)

4. Never, never, NEVER microwave or heat food in polystyrene containers.

Mark is a writer, financial analyst, Web developer, environmentalist, and, as necessary, chef and janitor. Grinning Planet is an expression of Mark's enthusiasm for all things humorous and green, as well as a psychotic desire to work himself half-to-death. Hobbies include health foods, music, getting frustrated over politics, and occasionally lecturing the TV set on how uncreative it is. For jokes, cartoons, and more great environmental information, visit

© 2006 Mark Jeantheau

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