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Know Your Plastics

Have you heard the claims of potential dangers associated with plastics that package our food and drinks?  After learning that certain toxic chemicals can leach into our food from the plastics in tupperware, I purchased glass storage containers and have avoided cooking or heating food in plastic containers.  I had also heard the same about certain toxins leaching into water from those plastic water bottles, so I purchased a stainless steel water jug (but unfortunately the convenience of those 16 oz Arrowhead bottles often wins out).  And, I had heard about dangers associated with a chemical called BPA in plastics and the linings of cans, so I try find BPA-free canned goods and plastics….But even though I made these changes out of an abundance of caution, I couldn’t explain to others why it was important.

So what’s the deal with plastic?  Why is BPA dangerous? And what are those numbers inscribed on the bottom of most plastic bottles and food containers? (Pick up most any plastic product around you and you’ll see the number inside the small triangle symbol).  I found several great websites that explain the ins-and-outs of plastics and offer helpful tips to take the confusion out of “best plastic practices” on a daily basis (without driving yourself too crazy :-) ).

What is plastic? What are phthalates and why should I avoid them?

Plastics are created by linking together molecules derived from petroleum, gas or coal (not so appetizing to think about eating off of that… :-)) and then adding various chemicals to produce the final product.  Of the thousands of chemical additives, one type commonly added are called ‘plasticizers’, which make the plastic more flexible.  These plasticizers are generally a type of chemical called phthalates. Because phthalates are not chemically bound to the plastics they’re added to, they can leach out and into the food or liquids the plastic is holding — especially if exposed to extreme heat or cold (e.g., sticking it in the microwave or freezer).

The CDC notes that the primary way people are exposed to phthalates is by eating and drinking foods that have been in contact with containers and products containing phthalates.   The CDC also states that human health effects from exposure to low levels of phthalates are unknown, but that some types of phthalates have affected the reproductive system of laboratory animals.  More research is needed to assess the human health effects of exposure to phthalates, but since they have been shown to disrupt the endocrine system and have been linked to numerous health conditions including cancers, I would say it’s best to avoid exposure via food and drink we ingest when possible.  (Many of the phthalate chemicals have been banned in Europe and the U.S. for use in certain products, such as toys, and back in 2008 two of the largest toy retailers — Wal-Mart and Toys R Us (and Babies R Us) —  announced new guidelines to reduce children’s exposure to phthalates in their toys; they were even applauded by US Senator Diane Feinstein.)

(Phthalates are also found in an amazing array of personal care items and can be absorbed through the skin – more on that to come in a future post).

What is BPA and why is it a problem? 

Another common plastic is polycarbonate – this is the plastic that contains the BPA (bisphenol A) that many of us have heard about.  Why is BPA a problem?  According to the Life Without Plastics website:

BPA is a concern because it readily breaks down and leaches from products made out of it. Plastics and resins made of BPA weaken, and thus leach more BPA, when they are old and wearing out, heated or frozen, washed with detergents, and exposed to oily or acidic foods and liquids. Thus, BPA leaching is especially a concern with canned foods, which often are oil-based and/or acidic.

BPA is often described as a hormone or endocrine disuptor, because it mimics hormones, in particular the human estrogen hormones, which are involved in normal cellular function, reproduction, development and behaviour.

Peer-reviewed scientific studies have linked BPA to numerous health problems including chromosomal and reproductive system abnormalities, impaired brain and neurological functions, cancer, cardiovascular system damage, adult-onset diabetes, early puberty, obesity and resistance to chemotherapy. Research into the impacts of BPA on human health is extensive and ongoing.

And recently, a study published in July 2013 by researchers at Brigham and Women’s Hospital in Boston found that BPA interferes with the maturation of human eggs, thereby reducing fertility.  The researchers tested the effects of BPA on 351 eggs from 121 consenting patients at a fertility clinic and found that BPA exposure may cause a significant disruption to the reproductive process. (See another article discussing BPA exposure here).

Because BPA can leach out of plastic and is commonly found in the linings of canned goods, plastic water bottles and even plastic baby bottles and pacifiers, it makes sense to avoid these when we can.  Especially for parents of young children, best not to have them sucking on BPA all day!  The U.S. Department of Health and Human Services even advises parents to take steps to minimize their children’s exposure and offers some very helpful tips.  

What are those numbers on the bottom of my plastics?

Those numbers are called the Resin Identification Code numbers and they indicate  what kind of plastic the product is made out of.   While they were originally created to facilitate recycling of plastics, by knowing the resin code of a product, we can know the materials in the plastic and potential risks.  The consensus from the information I found is that it is best to avoid plastics numbered 1, 3, 6 and 7 (polycarbonate), all of which have been shown to leach dangerous chemicals and to try to stick to numbers 2, 4, 5 and 7 (other than polycarbonate) whenever possible.

Below is a summary of each of the types of plastic from Dr. Joseph Mercola’s article on “How to Recognize the Plastics that are Hazardous to You.”.

Plastic #1: Polyethylene Terephthalate (PET) – TRY TO AVOID
This is the thin, clear plastic typically used to make bottles for water, soft drinks, mouthwash, sports drinks and containers for condiments like ketchup, and salad dressing.  PET is considered safe, but it can actually leach the toxic metal used during its manufacture (so if you do use it, best not to re-fill, re-use or heat it).  A study of bottled water found that the longer a bottle of water sits on a shelf — in a grocery store or your refrigerator — the greater the dose of metal present. And it is believed that more metal will leach at higher temperatures and exposures to sunlight.

Plastic #2: High Density Polyethylene (HDPE)
This is the thicker more opaque plastic often used for milk and water jugs, juice bottles, cleaning supplies and shampoo bottles.  It’s also used to make grocery bags and cereal box liners.  While it may be considered safer than others, HDPE (like most plastics) has been found to release estrogenic chemicals.  In one study, 95 percent of all plastic products tested were positive for estrogenic activity, meaning they can potentially disrupt your hormones and even alter the structure of human cells, posing risks to infants and children.

Plastic #3: Polyvinyl Chloride (PVC) – TRY TO AVOID
PVC plastic is commonly found in things such as shrink wrap, deli and meat wrap, plastic toys, and table cloths. PVC contains toxic chemicals including DEHP,  phthalate known to be an endocrine disruptor.

Plastic #4: Low Density Polyethylene (LDPE)
LDPE is used in the plastic bags for bread, newspapers, fresh produce, household garbage and frozen foods, as well as in paper milk cartons and hot and cold beverage cups. While LDPE does not contain BPA, it may pose risks of leaching estrogenic chemicals, similar to HDPE.

Plastic #5: Polypropylene (PP)
PP plastic is used to make containers for yogurt, deli foods, medications and takeout meals. While polypropylene is said to have a high heat tolerance making it unlikely to leach chemicals, at least one study found that PP plastic ware used for laboratory studies did leach at least two chemicals.

Plastic #6: Polystyrene (PS) – TRY TO AVOID
Polystyrene, also known as Styrofoam, is used to make cups, plates, bowls, take-out containers, meat trays and more. Polystyrene is known to leach styrene, which can damage your nervous system and is linked to cancer, into your food.  Temperature has been found to play a role in how much styrene leaches from polystyrene containers, which means using them for hot foods and beverages (such as hot coffee in a polystyrene cup) may be worst of all.

Plastic #7: Other – TRY TO AVOID
This is a catch-all designation used to describe products made from other plastic resins not described above, or those made from a combination of plastics. It’s difficult to know for sure what types of toxins may be in #7 plastics, but there’s a good chance it often contains BPA or the new, equally concerning chemical on the block in the bisphenol class known as Bisphenol-S (BPS) – both known endocrine disruptors.

The take away: if you have a choice, try to avoid plastics 1, 3, 6 and 7 when you can.  

Of course you probably can’t completely eliminate your exposure to BPA, phthalates and other chemicals from plastics (and you’d probably drive yourself crazy trying!), but there are certainly some simple things we can do to reduce our exposure.

Some Simple Safer Plastic Tips:  

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  • For drinking water, try to avoid plastic bottles.  If you do use plastic bottles made from #1 or #2 plastic try not to reuse them as they are intended only for single use.  One alternative is a refillable glass or stainless steel water bottle.
  • Purchase water bottles and other hard plastics and canned goods that are labeled “BPA-free.”
  • Invest in glass or stainless steel food storage containers to replace your plastic tupperware — especially for storage of oily or fatty foods.  Leaching increases when plastic comes into contact with oily or fatty foods, or when the plastic is scratched, worn, cracked, or sticky (so definitely get rid of those older plastic containers).  Glass mason jars also make great food and drink containers.
  • Don’t reheat food in a plastic container unless it is clearly marked “microwave safe” (not many are) – but probably best to use glass even if it is marked “microwave safe”.  Heating plastic in the microwave can cause it to degrade and leach chemicals faster. 
  • Use waxed paper or a paper towel to cover foods instead of cling wraps.  If you do use cling or plastic wrap, use it only for food storage and not for reheating.  And especially avoid storing fatty foods, like meat or cheese, in cling or plastic wrap, as these foods are the most likely to absorb chemicals from the wrap (ever get that “plastic” taste that clings to food after being wrapped in plastic?)
  • Try to avoid plastic dishes and utensils for meals.


Hope this has been helpful in clarifying some of the mystery around plastics.

For more information and some very good suggestions on plastic-free products, definitely check out Life Without Plastics!


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7 Responses to Know Your Plastics – How to Pick the Safest Products

  1. Rusty says:

    Extremely instructive. I have been looking for that information. Thanks. Again, great website.

  2. Barb Mena says:

    Incredible info Very useful. Know you have done lots of research. Thank you

  3. […] if you get your filtered/purified water and take it with you, be sure to try to avoid those plastic BPA water bottles! A glass or stainless steel bottle is best… there are some BPA-free plastics, but I’ve […]

  4. […] have written before about the importance of avoiding BPA/phtalates and those plastic water bottles and fo…, so why not get some great plastic-free alternatives for family and friends and protect their […]

  5. Baxter Abel says:

    I appreciate your tips to try and use plastics that are labeled as “BPA-free”. I wonder how the engineering process is different for BPA-free plastics than for regular plastics. Thanks for the tips! I’ll be more aware when I am looking for different types of plastics now.

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