Canned food: Yes, it's full of salt, but could that innocuous can be harboring a "global threat"? It could, all thanks to bisphenol A, or BPA, a chemical used to make canned-food linings. BPA falls into a class of chemicals known as endocrine disruptors, which act like hormones in your body. But could they also be increasing rates of chronic disease and infertility, and even contributing to the population decline of some wildlife species. The damage they're causing is so pronounced that a new report from the World Health Organization and the United Nations Environment Programme has dubbed endocrine disruptors a "global threat."
"Never has there been a time in history that the disease burden of the human population is predominantly chronic disease, not communicable or infectious disease," says Thomas Zoeller, PhD, professor of biology at the University of Massachusetts, Amherst, and a coauthor of the report. Many of these diseases, such as diabetes, thyroid disease, obesity, infertility, and breast and prostate cancers, are diseases of the endocrine system. At the same time, 18 percent of children worldwide are now being diagnosed with attention-deficit and autism-spectrum disorders, he says, both of which are developmental problems influenced by hormones.
What is a "Hormone Disruptor" Anyway?
"We can't prove that this is related to endocrine-disrupting chemicals, but we can't continue to deny that these disease trends are occurring," Zoeller says. And the evidence laid out in the report, "State of the Science of Endocrine Disrupting Chemicals", offers some serious food for thought. Much more is known about endocrine-disrupting chemicals now than a decade ago when the United Nations and World Health Organization first looked into these bad actors.
What They Are
The class of chemicals dubbed endocrine disruptors includes 800 chemicals suspected of acting like estrogen, testosterone, or other hormones once inside your body. It includes BPA, the chemical used in canned-food linings; phthalates, chemicals used in plastics to keep them pliable and in scented products to fix artificial fragrances; certain pesticides; brominated flame retardants used in cars, furniture, and electronics; and now-banned chemicals such as DDT, PCBs, and diethylstilbesterol (a drug once prescribed to pregnant women to prevent miscarriages that was later linked to cancer).
These chemicals interfere with the operation of your endocrine system, which controls hormones that impact nearly every organ of your body—your heart, kidneys, pancreas, reproductive organs, and brain—as well as regulating your thyroid and even how much fat your body stores.
What They Do
It will never be possible to link a specific endocrine disruptor to a specific ailment, Zoeller says, simply because there are too many external factors, such as lifestyle and genetics, that play a role in chronic diseases. But, the report concluded, "The speed with which the increases in disease incidence have occurred in recent decades rules out genetic factors as the sole plausible explanation. Environmental and other nongenetic factors…are also at play."
Here's some of the "mounting evidence" the report's authors identified after analyzing the animal and human population studies that have been done on endocrine disruptors:
• Animal studies suggest that exposure to endocrine disruptors during pregnancy and early neonatal development affects breast and uterine development, which in turn can speed up (or delay) puberty, cause infertility, and trigger uterine fibroids or endometriosis. They're also suspected of leading to low sperm quality in men, a problem that affects approximately 40 percent of men worldwide. In some cases, endocrine-disruptor exposure during pregnancy has been pegged to skewed birth ratios, where more girls are born than boys.
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• PCBs, brominated flame retardants, phthalates, BPA, and perfluorinated chemicals (which are used to manufacture nonstick finishes and stain-repellent clothing) are strongly associated with reduced thyroid hormones. Severe thyroid deficiencies can lead to brain damage, low IQ, ADHD, and even autism in children. In adults, even thyroid levels that are on the low end of the normal range can raise cholesterol and blood pressure levels, while also reducing bone density in women.
• More and more research in animals is pegging chemicals like BPA, pesticides, perfluorinated chemicals, and phthalates and the heavy metal lead to metabolic disorders like obesity and diabetes, given that these endocrine disruptors can interfere with hormones that control production of fat tissue and muscle, as well as influence functioning of the pancreas, liver and gastrointestinal tract.
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• Autoimmune disorders, such as allergies and endometriosis, are closely tied to endocrine system problems, and "sufficient" evidence suggests that chemicals likely play a role in those, as well. For instance, certain chemicals can interfere with receptors that regulate white blood cell formation, a marker for inflammation and immune disorders.
What You Can Do about It
"The most important issue that people need to recognize—both legislative bodies as well as the general public—is that chemicals in the environment are affecting human health," says Zoeller, "and the regulatory approach for assuring safety is not adequate."
In the U.S., chemicals are innocent until proven guilty, and they're defended vociferously by the trade-supported American Chemistry Council, which often criticizes studies of the effects of chemicals like BPA and phthalates for not offering adequate proof for their conclusions.
EPA to Study Chemical Safety in a Way That Actually Matters
But, as Zoeller noted, hard proof in the field of endocrinology and chemical influence will never exist. Nonetheless, as he told Environmental Health News, "for BPA, the science is done. Flame retardants, phthalates…the science is done. We have more than enough information on these chemicals to make the reasonable decision to ban, or at least take steps to limit exposure."
Since bans on chemicals are rare in the U.S., you'll have to limit exposure yourself. Here are a few easy steps you can take:
• Demand organic. Endocrine-disrupting pesticides include atrazine, 2,4-D, and a class called organophosphates, all common on nonorganic foods.
• Don't use pesticides in or around your home. Just as you shouldn't eat pesticides with your food, you shouldn't inhale them, drink water tainted with them, or expose your skin so your absorbs them through it. Use natural pest-control methods and nontoxic lawn and garden tactics from Organic Gardening magazine.
• Avoid plastics and canned food. If you do, you'll avoid the endocrine disruptors, such as phthalates and BPA, that are used to make them. Opt for stainless steel or glass food storage and buy food sold in glass bottles rather than cans.
• Clean your home greener. Commercial cleaning products contain an array of endocrine disruptors, whether it's the phthalates and benzene that waft out of scented candles or the harsh solvents used in oven cleaners and soap-scum removers. Here's How to Make Green Cleaning Recipes That Really Work.
• Clean yourself greener. Endocrine-disrupting chemicals like phthalates, benzene, parabens, and glycol ethers are pervasive in cosmetics and personal care products. Check the Environmental Working Group's Skin Deep Cosmetic Safety Database to rate the safety of products you use and to find safer ones if you need to.
Published on: February 20, 2013
Updated on: February 21, 2013