Even nutritionists have dietary blind spots; mine has been plastics.
Having written about them extensively here and in my book, I'd been very careful to avoid food containers, bottles and cans containing bisphenol-a (BPA), a man-made chemical thought to disrupt the body's natural hormone balance.
But despite my husband's long-time nagging to make our kitchen a "plastic-free-zone," I had been reluctant to throw out faithful kitchen companions that I believed to be BPA-free - and therefore harmless - like my mixing bowls, food storage boxes, chopping boards and gaily colored drinking cups. A combination of frugality and laziness prevented me from discarding what seemed like perfectly good kitchen equipment and spending many hours and dollars replacing it all.
That is, until my husband forwarded me this eye-opening article by Californian holistic health practitioner Chris Kresser about a study which found that even BPA-free plastics contain chemicals with estrogenic activity.
I realise now that "BPA-free" doesn't mean free from endocrine disruptors. Far from it: in fact, the study shows that in some cases, the estrogenic activity from BPA-free plastics is stronger than that of BPA!
Chemicals that have estrogenic activity - i.e. that mimic the body's own estrogens - are associated with a range of health problems: early puberty in females, reduced sperm counts, altered functions of reproductive organs, obesity, altered sex-specific behaviors, and increased rates of some breast, ovarian, testicular, and prostate cancers. They are thought to be particularly dangerous to fetuses, infants and children, but may affect adults too, as recent studies have indicated.
One study, for example, found that even at weak concentrations, BPA can block the effects of several commonly used chemotherapy agents on breast cancer cells. While BPA has been studied mostly in animals, only last month two human studies linked BPA to behavior problems in girls and diabetes in adults.
For the BPA-free plastics study, researchers bought 455 plastic products such as deli containers, plastic bags, food storage boxes, baby bottle components and food wraps from large retailers like Wal-Mart, Whole Foods, Trader Joe's or Target. Then they put the plastics in contact with liquids that contain the sorts of 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).
The results are shocking: over 90 per cent of the products leached estrogenic chemicals before they were even stressed, and after being stressed almost all of the products showed estrogenic activity.
Worryingly, it's impossible to know which type of plastic product may have stronger estrogenic activity than any other, because the chemical composition of commercially available plastics is their manufacturers' secret. A single part of any plastic product may consist of 5-30 chemicals, and an item containing many parts (e.g., a baby bottle) may comprise more than 100 chemicals, almost all of which can leach from the product, especially when stressed, the researchers note.
According to the study's authors there are plastics that do not exhibit estrogenic activity, even when stressed, wand hich could be produced at minimal additional cost. Until these become commercially available, however, I suggest we declare our homes plastic-free zones.
Reducing our use of plastic has other benefits than "just" health. For one, after the initial outlay for non-plastic replacements, you will probably save money, for instance by carrying filtered water in a stainless-steel bottle rather than buying expensive bottled water, or preparing food from scratch (generally cheaper than packaged foods).
You will also reduce the amount of plastic garbage whose disposal is causing massive environmental problems. You may even discover the esthetic and tactile pleasure of handling time-honored natural materials like wood, earthenware, glass, iron and china. What better way to honor the fresh, unprocessed foods carefully grown by local farmers than to prepare and serve them in natural materials?
This doesn't mean you can never touch plastic again. If you're hiking on a sunny day and forgot to bring your stainless-steel or glass bottle, it's better to drink water from a plastic bottle than risk dehydration!
At home, however, there are many small ways in which we can shift from plastic to more chemically inert materials. For instance:
Three years ago Beth Terry started a blog, My Plastic-Free Life, in which she charts her progress towards de-plasticising her life, and offers 95 simple suggestions (to date) for ways to reduce plastic in our lives. If you can think of other ways of cutting back on plastic, please suggest them in the comments section below.
Copyright Conner Middelmann-Whitney. Conner is a nutritionist, health writer and cooking instructor; she posts weekly anti-cancer cooking videos on YouTube. She recently published Zest for Life, The Mediterranean Anti-Cancer Diet, a cancer-prevention nutrition guide and cookbook based on the traditional Mediterranean diet (available at Amazon, Barnes & Noble and other online bookstores). Conner offers nutrition consultations via Skype; please consult her website for details.