How Plastic Food Containers Can Make You Sick | Chris Kresser
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How Plastic Food Containers Could Be Making You Fat, Infertile and Sick


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In previous articles here, here and here, I wrote about the dangers of an environmental toxin called bisphenol-A (BPA). BPA is a chemical that is found in several plastics and plastic additives. It’s in the water bottles some folks carry to gyms, the canned tomatoes and coconut milk they cook with, and in the baby bottles moms use to feed their infants.

We’ve known for decades that BPA has estrogenic activity. In vivo animal studies and in vitro cell-culture research has linked low-level estrogenic activity associated with BPA exposure to all kinds of fun stuff, like diabetes, ADHD, heart disease, infertility and cancer.

There is now significant evidence suggesting that even low levels of BPA-exposure can cause harm, and this is particularly true in vulnerable populations like pregnant women, infants and the chronically ill. (1)

Because of this research, and the growing public awareness that BPA should be avoided, a new crop of “BPA-free” plastic food containers and baby bottles has been introduced. However, a recent study published in the journal Environmental Health Perspectives in July has shown that even BPA-free plastics have chemicals with estrogenic activity (EA), and can cause serious health problems as a result. (2)

What is “estrogenic activity” (EA)?

Chemicals with estrogenic activity (EA) are those that mimic or antagonize the actions of naturally occurring estrogens. These chemicals are capable of binding with one or more of the nuclear estrogen receptors in the body.

The best way to think of chemicals with EA is as a counterfeit key fitting into a loose lock.

When these chemicals activate the estrogen receptor, they produce an increase in circulating estrogen, which in turn can cause problems such as early puberty in females, reduced sperm counts, altered function of the reproductive organs, obesity, increased rates of certain cancers and problems with infant and childhood development. (3)

As I mentioned above, vulnerable populations such as pregnant women, developing fetuses, infants and children are especially sensitive to even very low doses of chemicals with EA. (4)

BPA-free is not EA-free

In the Environmental Health Perspectives study, Yaniger et al. set out to determine the estrogenic activity of commonly used plastic consumer products.

They bought more than 500 plastic products at places like Wal-Mart, Whole Foods, Trader Joe’s, Target, and other major retailers. They selected from all categories of plastic, including tupperware containers, bags and wraps.

Then they cut the containers into pieces, put them into liquids that contain similar chemicals found in food and drinks, and subjected them to stresses that mimic normal use, like UV light (sunlight), microwaving, or moist heat (like boiling or dishwashing).

Their results showed that over 90 percent of the products leached estrogenic chemicals before they were even stressed, and after being stressed essentially all of the products showed estrogenic activity.

According to Stuart Yaniger, one of the lead authors of the study:

Baby bottles, plastic bags, plastic wrap, clamshell food containers, stand-up pouches: Just about anything you can think of that’s made of plastic that food or beverages are wrapped up in, we found this activity. It was shocking to us.

What plastics do and don’t have EA? It’s impossible to tell.

Perhaps the most troubling outcome of this study is that it’s currently impossible to determine which consumer plastic products are likely to have chemicals with EA, and which are not.

The exact chemical composition of most plastic products is proprietary and thus not known, and a single plastic item containing many parts (e.g. a baby bottle) may consist of >100 chemicals, all of which can leach from the product.

In light of the researchers’ finding that nearly all of the 500 plastic products they tested leached when stressed, and 90 percent of them leached even without stress, I think it’s pretty safe to assume that most plastic products you can buy in the store have chemicals with EA.

It’s important to reiterate that this is true even with BPA-free plastics. In fact, the Environmental Health Perspectives study found that some BPA-free products had even more EA than BPA-containing products!

Should you be concerned about chemicals with EA?

There are still a lot of unknowns in the discussion of the EA of various chemicals in plastic products, such as the number of chemicals having EA, their relative EA, their release rate under different conditions, and their half-lives in human beings of different ages.

However, there are 3 strong arguments for being “better safe than sorry” when it comes to plastics and EA (5):

  • in vitro data overwhelmingly show that exposures to chemicals with EA (even in very low doses) change the structure and function of human cell types;
  • many studies present clear cellular, molecular and systemic mechanisms by which chemicals having EA produce changes in cells, organs and behaviors; and,
  • recent epidemiological studies strongly suggest that chemicals with EA produce measurable changes in the health of various human populations.

Perhaps the study authors summed it up best in their conclusion:

Many scientists believe that it is not appropriate to bet our health and that of future generations on an assumption that known cellular effects of chemicals having EA released from most plastics will have no severe adverse health effects.

I couldn’t agree more.

What you can do to reduce your exposure to chemicals with EA

Here’s a list of things you can do to reduce your exposure – and especially your baby’s and children’s exposure – to chemicals with EA.

  • Use glass containers and canning jars at home for food storage. Be aware that the lids of Mason and Kerr brand canning jars contain BPA and chemicals with EA. There are BPA-free lids, but they still may contain chemicals with EA, and I’ve been told they’re made with formaldehyde. Weck makes 100% glass jars that are a good alternative. Crate and Barrel sells them here.
  • Use stainless steel containers in the freezer instead of freezer bags.
  • Use a stainless steel water bottle (like the Klean Kanteen) instead of plastic bottles.
  • Don’t drink bottled water from plastic bottles, especially when they’ve been exposed to sunlight.
  • Parents: use glass baby bottles instead of plastic. Evenflo is a commonly available brand you can buy at Target, Wal-Mart, Walgreens, Rite-Aid, etc. and online at Amazon and other retailers.

Special note for Sous Vide users: After reading this study, I’m feeling very uncomfortable about the idea of eating anything that comes out of a plastic bag that has been sitting in a hot water bath for several hours. This is a crushing blow, as I love cooking with the Sous Vide. But in light of the evidence that even BPA-free plastics bags leach chemicals with EA even without added stress like a hot water bath, I think erring on the side of caution is probably wise.

UPDATE 10-28-11: make sure to read the comments section for some good recommendations.

UPDATE 11-7-11: check out this article on Nom Nom Paleo, one of my favorite Paleo food blogs. She did some homework and found some information claiming that re-usable silicon bags don’t have EA chemicals. However, Stuart Yaniger, one of the authors of the paper I referenced in this article, commented on her post (and below) that most silicon products do, in fact, leach EA chemicals. I’m also wary of the claim that FoodSaver bags don’t have any EA without 3rd party, independent testing. As Yaniger’s article demonstrated, we should assume all plastics have EA until proven otherwise.

Resources for those who want to avoid plastic entirely


Join the conversation

  1. My sonand I are very allergic to Nickel and I believe someone said stainless steel had nickel in it and and it was cancerous.
    So silverware that’s not silver but used everyday for forks, knives and spoons? They get heated in a plastic dishwasher with hot water, do they leech nickel?

  2. What about plastic and freezing foods? Soups, raw meat, fruits for smoothies – have any studies been done about leaching and freezer contact with say, zip lock bags or food grade plastic? Tks

  3. Thanks for the thoughtful and informative essay, Chris.

    All of this angst over plastics is very concerning and disturbing to me. I have a neurological condition that makes it difficult for me to hold on to objects for any length of time; I have injured myself requiring stitches more than once from dropping glassware or ceramicware. For my safety I have rid my kitchen of anything except plasticware, with the exception of three Pyrex™ bowls to use in the microwave and two large mugs for hearty soups in the winter. Now I find out about BPAs and EAs and wonder if I am doomed. This morning I made my coffee in one of those soup mugs and set it on the desk so I would not have to lift it and put myself at risk, but then I realized I was drinking it through a plastic straw.
    I suppose I will find it necessary to weigh the relativity of danger; I have hurt myself terribly with glass much more than I will probably be hurt by chemicals in plastics, though I am probably a walking repository for BPAs and EAs and whatever else is lurking in the plastics.
    I live alone, so there is no one to absorb the chemicals except for me and the pets whom I feed in plastic bowls or dispensers. Also, I am a child of the days before plastics and was breast-fed and raised using glass and rubber and cast iron and paper and other natural products in food preparation and storage, so I’m ahead of the game there. (In fact, I remember the hoopla when plastic bags for bread appeared in the markets, plastic bottles for milk came about, and bathroom products were made safe by putting them in plastics.) I even remember Disneyland (Anaheim, CA) in 1957 having Monsanto’s “House of the Future” which was a plastic (and Fiberglas™) house with plastic appliances, which, when it came time to dismantle the exhibit in 1967, proved to be nearly impossible to take down, turning a one-day project into one lasting at least two weeks.
    Oh well, I suppose I will continue to rate the risks to myself on a relative scale as I use my plastic straw on my Formica™ desktop while typing this on my plastic keyboard and computer wearing my polyester clothing and Crocs™ shoes while also planning a trip to the grocery store in my truck with its plastics-and-polyester interior to buy more of the food packaged in plastic-lined materials.
    We can run, folks, but we can’t hide.

  4. I too, am concerned about the dangers of modern-day living, but plastics are just the tip of an enormous iceberg. The air is horrible, the water polluted, our food toxic. It can be overwhelming to think about. Of course, we’re all still here and have obviously adapted to this dangerous world to some degree, as did those who came before us. While I believe in living healthy as much as possible, we have to stay mentally healthy too, and avoid anxiety about things beyond our control. I do what I can (use glass, stainless cookware, eat organically, drink filtered purified water from home, recycle, adopt rescue pets, exercise, avoid drugs, alcohol or smoking, get fresh air and sunshine, think happy thoughts, pray, etc . . .) Even if there were alternatives to every toxic thing we encountered, we couldn’t possibly avoid everything or afford it all. Live simply, make health-promoting changes, love deeply, laugh often, get plenty of sleep, be kind to others, go for walks, make memories, see the sights and forget the rest for the little time you occupy space here. Let it go and move forward with peace and love.

  5. Great information, thanks. This may have been previously addressed (limited time right now), however am interested in where one can buy toxic-free utensils in boxed sets, utensil covers for portability/hygiene, and where to recommend large-group events/businesses for bulk unit toxic-free utensil purchases. Thank you, in advance, of your reply and time.

  6. I am seriously considering purchasing a Sous Vide Supreme, but I do not want to use any plastic in my cooking and would like input on whether and why the following proposed usage of the appliance might be discouraged…

    Use case: lengthy ultra-low-temperature-poaching of unpackaged proteins

    Example: Fill a Sous Vide Supreme with water, heat it to 140F, drop in salted short ribs (not packaged in any plastic bag or any other container), remove them after 72 hours, and then separately consume both the liquid and the ribs.

    I have 3 questions about this proposed use case:

    (1) Would there be any food safety concerns in using the Sous Vide Supreme to perform lengthy ultra-low-temperature-poaching of proteins by placing the protein directly into the water bath, i.e. not first inserting the protein into any packaging or any other container whatsoever? (I acknowledge that some of the flavor and nutrients would likely migrate out of the protein and into the water, but I would plan to consume that cooking liquid as a soup/broth later, so that’s not a reason to discourage me.)

    (2) Would it indeed be safe to consume this cooking liquid after that 72 hour period? Perhaps I should separately bring it to a simmer before consumption.

    (3) The only reason I can surmise this lengthy ultra-low-temperature-poaching of unpackaged proteins may be dangerous to our health is if, at such a low temperature (140F) for such a long period of time (72 hours), since the air above the water bath may cause the upper surface of the liquid to be at a reduced temperature, there may be bacteria or toxins multiplying on the surface of the water bath’s liquid or on small food particles that float to the surface. Is that a concern?

  7. great article keep up the great work we all need to spread the word and get this information out as fast as is possible!

  8. What about the plastic cups from Starbucks? I always order an Americana and the coffee is brewed to drip in the plastic.

    • Take away cups are one of the worst offenders. The hot, acidic liquid makes leaching of plastic from the lids and lining of cup very strong. Solution – take your own ceramic mug with you. I thought about buying one with a silicone lid, but it seems these might leach EA too. Somebody should manufacture a mug with a ceramic sip top!

  9. What about our motor vehicles? They sit in the sun most of the time. There’s a lot of plastic inside which gets really hot and it must leach out a lot of chemicals into the air that we breathe. Maybe we should be winding down our windows as soon as we get in and blast out the contaminated air as quickly as possible. Still, we are driving for hours at a time sometimes and that’s a long time to be breathing in toxic air.
    We just can’t escape from our plastic worlds – vacuum cleaner, sewing machine, fridge, freezer, tv, dvd players, knife handles, utensils, heaters, exhaust fans, light covers, vitamin/medicine bottles, etc etc – the list is unending.
    I try not to use a microwave at all as it is so bad – I saw an experiment where microwaved (and cooled) water was used to water a plant. An identical plant was watered with ‘normal’ water. The microwaved water made the plant sickly, whereas the ‘normal’ watered plant thrived. What does it do to our food then?
    What are peoples’ thoughts on rainwater tanks instead of plastic filtration systems?
    At best, we can just eliminate as much plastic as we all individually can, and hopefully that’ll be enough to make a difference 🙂

    • You’re correct about offgassing from cars and other consumer projects, including the computer you’re reading and writing with.

      That said I think you should take the video you describe of microwaved water with a very large grain of salt, and seek a great deal of corroboration before you believe the claim that microwaved water has been changed in a way dangerous to life. Which is to say, it’s nonsense, and if you’re going to accept claims like those in the article which are well-informed by chemical and physical science, you’ll also need to filter out pseudoscientific spectacle.

      There is still a risk to using a microwave oven if you’re near it while it’s operating – it’s not perfectly shielded (put one near a 2.8GHz Wifi gateway for evidence of this – not a newer 802.11n 5GHz though). The inverse square nature of radiation in space means that you can simply move away a few steps and lower that dose to the same ambient microwave radiation you already get from the sun-warmed atmosphere. Microwaves are literally everywhere in the universe; they’re simply faster-vibrating and more energetic radio waves.

      None of which undermines the point of the article – all plastics leach endocrine-disrupting chemicals, particularly when you subject them to heat, chemical stress, or other forms of energy. They’re just not especially stable materials.

  10. What about cutting boards for vegetables?? I assume those are not good either? Should we use stainless steel?

  11. There is just one problem with stainless steel containers: They contain nickel and chromium. Even food grade stainless steel does. Nickel is a carcinogenic. Of course, any food grade stainless steel producer says there is no leak – but if you use these products day in day out, there is going to be a leak.

    Plastipure supposedly is EA free.

    I would love to hear your take on this.

  12. In the wake of the recent mother jones article, I am trying to eliminate as much plastic from my family’s lives as possible. I have the following questions:
    1) Is leaching only a problem if the food/liquid comes in physical contact with the plastic or if you use a top that doesn’t touch it can it still leach in a closed container?
    2) Does it matter how long the food is in contact with the plastic (momentary versus days)?
    3) Weck jars have rubber rings for their glass lids. Are these problematic? Likewise, there are other glass containers with glass lids that use silicone or rubber to make an airtight seal. Is that still problematic?
    4) I am using stainless steel straw cups for my 3 year old and 1 year old. However, I cannot find any that do not use silicone straws. Is there an alternative?
    5) In general, if you have to use silicone or plastic is one better?
    6) Which is safest to use: wax paper, parchment paper or aluminum foil?
    7) Are there any concerns with stainless steel?
    8) Are store bought glass jars of applesauce, jam, pasta sauce, etc. safe or are there concerns about the tops used for these products?
    9) what about plastic baby toys (that are bpa free)?
    10) what about plastic products that are made from plants (like corn)?

    Please let me know if you have some answers. I appreciate your help.

  13. Eastman has been found out; big coverup akin to the tobacco industry’s tactics. Their Tritan plastic is possibly worse than BPA.

    No, you can’t eliminate all plastic, but certainly minimizing it on things we ingest has to be the most practical and highest return-on-investment, both money- and time-wise to potentially improve our health. So that means no plastic stress (micro, dishwasher, reusing easily squashable & thus probably weaker structure/more leachable to-go containers) and reducing time of contact and surface area in contact between food and plastic surfaces. I’m going to go with stainless tiffins & pyrex dishes probably with rubber lids, mason/Weck jars, etc., and not worry TOO much about non-liquids in contact with my OXO countertop vacuum storage containers (flour, etc.), mixing bowls used for only a few minutes at room temperature, and the like. Not giving up my CamelBak bladder for hiking, but may switch out my daily water bottle with stainless.

  14. Ugh, this is so depressing! Where can I get safe drinking water then? The tap water has hormones in it, and most bottled water will have EAs, and I can’t find a solid answer on whether water filters will get the hormones out of my tap water, so now what? What the heck do I drink??

    • I have a Pure Effect Water filter which filters out hormones, among other things.

      I purchased an ULTRA-UC and then upgraded to the ULTRA-UC-DISINFECT model. I was pleased with both purchases. BTW, over time, it costs the same or a little more for filtering vs bottled water, minus the soft plastic.

      I am not with the company, but I have recommended it to several people.

  15. I noticed back in 2011 shortly after you wrote this article someone asked about freezing food in bpa free ziplock type bags and you indicated you were still researching that. When I do this I always put the food in once it’s cold or room temperature but am interested in what you’ve found out. I don’t want to keep storing food this way if there is hard evidence that even this can leech EAs and other chemicals into our food. Thanks!

  16. I use klean kanteen spill proof cups for my girls! I thought they were safe, but now I’m nervous about the silicon spout??