Studies have shown that plasticizers such as BPA and phthalates and other potential endocrine disruptive chemicals can have harmful effects and may be contributing to several ongoing public health concerns.
Harvey Katz, MD, Associate Clinical Professor, Department of Population Medicine, Harvard Medical School, began his presentation titled “Hormones, Food, and Our Environment” at the 2013 Pri-Med East Conference and Exhibition by referring to Silent Spring, the classic book written by pioneer in environmental health Rachel Carson, whose work is credited with helping to launch the environmental movement.
Carson dedicated her book to Albert Schweitzer, who said: “Man has lost the capacity to foresee and to forestall. He will end by destroying the earth.” Katz, whose talk addressed the growing concern with the risks of environmental exposures and their effect on health, said, “This book should be required reading.”
The Endocrine Society defines an endocrine disruptive chemical (EDC) as: “Any exogenous chemical, or mixture of chemicals, that interferes with any aspect of hormone action.” Katz used a Patriots football analogy to illustrate this point, telling the audience to picture footballs thrown by Tom Brady football as the hormone coming in, and the Jets defense as the EDC keeping the hormone from landing where it is supposed to.
EDCs may explain many troubling phenomenon nowadays (eg, the trend toward earlier puberty, increasing infertility, and declining sperm counts). For example, Katz noted that soy is an endocrine disruptor as it is a phytoestrogen that can inhibit thyroid peroxidase activity. He advises that physicians should always include an “environmental history” when examining patients.
Common EDCs include plasticizers such as BPA (bisphenol A) and phthalates. Katz said that BPA is “everywhere” as it makes plastics more rigid (eg, the water bottles in the hands of a sizeable number of audience members), and has been linked to behavioral problems, obesity, kidney disease, asthma, and much more. He said there are many studies that found evidence linking BPA to clinical disorders, and that when he asked his assistant to find all BPA studies conducted over the last several years, she returned with over 2,000 examples.
Phthalates make plastics more flexible (eg, yellow rubber duckies). They are ubiquitous, being found in toys, solvents, soap, cosmetics, nail polish, IV tubing, vinyl flooring, garden hoses, and enteric-coated medications. Phthalates can be inhaled, ingested, and absorbed through the skin. In fact, Katz said that studies have shown they may block testosterone. Dysgenesis syndrome in an increasingly common developmental disorder with environmental aspects caused by phthalates; results can include testicular cancer and poor semen quality.
Katz provided several tips to avoid exposure to BPA and phthalates, including use glass whenever possible and buy only BPA- and phthalate-free products. Another tip is to be aware of the triangular recycle code stamped on the majority of plastic products—use 1, 2, 4, and 5 for foods and beverages, and avoid 3, 6, and 7. Don’t put plastic in the microwave oven to warm food or formula and don’t put plastic in the dishwasher.
Katz also addressed the food dilemma: organic or conventional? “Is it worth paying 10-40% more? And what do we tell our patients when they ask?” he said. Katz’s answer was that he believes organics may not be healthier, but they may be safer—based on 237 studies that compared them and found no nutritional difference, fewer pesticides, less hormone content, and fewer multi-resistant bacteria. He recommended that clinicians tell their patients about the Environmental Working Group Shopping Guide.
Katz said that with 80,000 chemicals already in use in the US, and with up to 2000 new chemicals being introduced into commerce each year (with no routine assessment of safety conducted by the EPA), there are takeaway points he wanted the audience to remember:
Katz concluded by recommending physicians and patients consult the reference Pediatric Environment Health, which he referred to as “the green book.” He also recommended Our Stolen Future, the sequel to Silent Spring.