Science of Food: Am I consuming BPA?
April 19, 2017
You have probably seen the label "BPA-free" on plastic bottles, food and beverage cans and other plastic food packaging materials. Have you wondered what exactly is BPA and why we are commonly seeing this label on our products recently? And what does this mean to the health and safety of consumers? Herein I will explain the chemistry of BPA and its replacement compound BPS, and I will provide some tips on how to avoid eating these potentially harmful man-made chemicals.
What is BPA?
BPA stands for bisphenol A. It is a synthetic chemical introduced commercially in the 1950s as a material for polycarbonate plastics. Because of its strong physical properties that make it resistant to breaking and cracking, it became a popular material for plastic bottles and as an epoxy resin for lining metal cans for food and beverages. It is so popular, in fact, that more than 6 billion pounds of BPA are used in consumer products each year.
Many studies have shown BPA can and does leach out of plastic containers and metal cans and into the food and drink we consume. Leaching occurs to a greater degree when the container is heated, run through a dishwasher or when harsh detergents are used.
Because plastic containers, plastic food packaging and canned foods are so common today, it is almost certain that all of us have BPA — or its replacement BPS — in our bodies. In 2004, the National Health and Nutrition Examination Survey found detectable levels of BPA in 93 percent of 2,517 urine samples from people 6 years of age and older. BPA has also been detected in amniotic fluid, fetal plasma and mothers' breast milk.
Is BPA harmful?
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The potential health risks of BPA exposure were first publicly observed in 1992 when Dr. David Feldman at Stanford University "realized that we had identified a molecule that was leaching out of the plastic that, due to its estrogenic hormone-like properties, was potentially dangerous to people eating out of containers made of this type of plastic."
In other words, BPA can act to mimic the hormone estrogen, due to its similarity in shape and chemical composition and is now classified as a general endocrine disruptor.
Our endocrine system is made up of all our hormones and corresponding glands and receptors that mediate numerous vital processes in our bodies. An endocrine disruptor such as BPA can bind to such a receptor and block the natural hormone from binding, which can alter the normal functioning of that hormone.
This may lead to overstimulation of normal cellular activity of that hormone or it can have the opposite effect, and can block the hormone from performing its normal function. "By now, thousands of studies have provided evidence that BPA is a prototypical endocrine-disrupting chemical that affects reproduction, neural development, behavior, cardiovascular functions and metabolism, as well as the promotion of several types of cancer," said Dr. Nira Ben-Jonathan, Ph.D., professor in the Department of Cancer and Cell Biology at the University of Cincinnati Medical School.
Despite these concerns from the scientific community, and the widespread human exposure to this chemical, the FDA still states "that BPA is safe at the current levels occurring in foods." However, after a report released by the U.S. National Toxicology Program in 2008 found "some concern for effects on the brain, behavior and prostate gland in fetuses, infants and children at current human exposures to bisphenol A," the FDA finally banned its use in baby bottles and children's cups in 2012, following the European Union, Canada and China.
BPS is the new BPA
With consumer concerns on the rise, many companies have started to abandon the use of BPA, which is why you see the label "BPA-free" on so many plastic products and metal cans. What most consumers don't know is the plastic industry has replaced BPA with a similar molecule called BPS (bisphenol S) that closely resembles the chemical structure of BPA.
"Despite hopes for a safer alternative to BPA, studies have shown BPS to exhibit similar estrogen-mimicking behavior to BPA," said Sumi Dinda, Ph.D., a professor at Oakland University School of Health Sciences and principal investigator of a study published in 2017 showing that BPS may increase the risk of breast cancer and cause breast cancer to become more aggressive.
And it's no surprise that BPS acts like BPA; this is how chemicals function in the body. Similar to how a key unlocks a door, the specific shape of the key is the primary factor that determines its ability to fit into the lock. Because BPS is so similar in its shape and chemical properties to BPA, it has the ability to bind to the same receptors that disrupt the normal functioning of our endocrine system.
Avoiding BPA and BPS
Unfortunately, products that claim to be "BPA-free" often still contain BPS — or other endocrine disruptors — as there are essentially no labeling requirements for this BPA replacement chemical. This makes it very difficult for us to avoid consuming BPS, which can still be used in baby bottles.
Instead of using plastic containers, try using glass, ceramic or stainless steel as an alternative. If you use plastic, avoid heating it in a microwave or putting hot food or drink into the plastic container. Scratched or old plastic containers can cause additional leaching so get rid of old plastic containers. Canned foods and aluminum beverage cans are usually lined with an epoxy resin that contains BPA or BPS, so limit consumption of foods out of a can and eat fresh food when possible. In addition to food containers, thermal paper-like store receipts also contain BPA. While the chemical is not readily absorbed through the skin, it does transfer to your skin and can be ingested if your hands touch your food or mouth.
We live in a world full of synthetic chemicals, something I began learning extensively about when I earned my doctorate in synthetic organic chemistry nearly 15 years ago, and we have the right to know if we are exposed to toxic chemicals from our food and environment.
Dr. Lisa Julian Ph.D. has a passion for organic chemistry the "molecules of life," and its application to food and health. She's the owner of Elevated Yoga & Holistic Health in Frisco and teaches Science and Nutrition at CU Denver and CMC. She can be reached at 970-401-2071 or firstname.lastname@example.org For more information about services offered at her studio, visit http://www.ElevatedYogaColorado.com.
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