What is BPA?

November 14th, 2012

It seems that in recent years the chemical “BPA” has become a big concern. Many companies that sell products like water bottles, for instance, now boast that their products do not contain BPA. When we are shopping, many of us check the tags of food-related plastic products for the words “BPA free” but we don’t even know what this phrase really means. So what is BPA and is it a chemical of concern or not?

Where is BPA found?

The abbreviation BPA stands for Bisphenol A. This chemical has been used since the 1960s to produce epoxy resins and polycarbonate plastics. Epoxy resins are typically used to coat metal products like bottle lids, canned foods, and water supply pipes. Polycarbonate plastic, which is a hard, clear plastic, is used in many items especially water and infant bottles, food storage containers, tableware, and even compact discs and medical devices. A product that has a recycle code of 3 or 7 may be made with BPA if it is a polycarbonate material.

How are you exposed to BPA?

Although BPA can be found in many common household items, humans are primarily exposed to BPA when it leaches from products into food and beverage items. While polycarbonate plastic is very durable, repeated exposure to high temperatures causes the plastic to break down and release the BPA. This can occur when you repeatedly heat food in BPA-containing plastics in the microwave or pour hot liquid into a plastic container that is composed of BPA. If the container is scratched, it may cause more BPA to be released when heated.

How much BPA are you exposed to every day?

Currently there is controversy over how much BPA we ingest daily. A 2003-2004 CDC National Health and Nutrition Examination Survey detected BPA in 93% of urine samples taken from a study group of 2,517 people aged six years and older. This raised many concerns about BPA and led to a study by the National Institute of Health’s National Toxicology Program (NTP) in 2008. This study tried to determine daily intake levels in various age groups and estimated that infant daily exposures range from 1 to 13 micrograms of BPA per kilogram bodyweight (µg/kg bw) while children up to the age of six can range from 0.043 to 14.7 µg/kg bw. Adults were estimated to only have a daily intake ranging from 0.008 to 1.5 ug/kg bw.

The FDA however disagrees with these estimates, claiming that they are too high. Since 2008 there have been more studies about BPA exposure and the FDA reports that average daily intake for infants is more likely to be 0.2 to 0.4 µg/kg bw while children and adults both share an average daily intake of about 0.1 to 0.2 µg/kg bw. The FDA’s National Center for Toxicological Research also developed a mathematical model of what happens to BPA inside the body. Apparently, it is not like other toxins that remain in the body tissues for long periods of time. BPA is quickly metabolized to an inactive form and eliminated in both children and adults. If this is true, it is good news because it means the BPA does not have as much time to cause long-lasting effects in the body.

What are the possible effects of BPA exposure?

According to the scientific studies, adults will not likely experience effects from BPA exposure. On the other hand, both the NTP and the FDA recognize the fact that infants, in particular, may have a greater risk of effects from BPA. Infants may not be able to metabolize and eliminate BPA as fast as children and adults since their liver, the organ that detoxifies the body, is still developing. Their neurological and endocrine (glandular) systems are also still developing and might be affected as well. Therefore, NTP and FDA believe there is some concern that infants may experience effects on the brain, prostate or mammary gland, and females may experience early puberty due to the alteration of hormones.

It is important to keep in mind that there is a lot of uncertainty concerning the studies conducted thus far. For instance, most experiments were performed using rodents or primates but not usually humans, making it difficult to know exactly how humans are affected. Also the studies use different experimental designs, meaning that the studies differ in how the test subjects are exposed and how the effects are measured. This lack of consistency between studies makes it difficult to compare the results. Uncertainties such as these mean that we need to be cautious that we are not underestimating or overestimating the risk of exposure and effects from BPA.

Err on the side of caution

FDA recognizes that there are many uncertainties that need to be clarified by more research. In the meantime, the FDA is trying to reduce exposure to BPA by supporting the development of BPA-free linings in infant formula cans as well as other food can linings. The FDA also encourages major manufacturers to stop selling infant bottles and feeding cups that contain BPA.

If you would like to limit your entire family’s exposure, it is recommended that if you purchase products that are marked with recycle codes 3 or 7 make certain they are not made of polycarbonate. If you use plastic containers made with BPA, do not put hot or boiling food or drinks into them and do not heat them in the microwave either. Remember to always discard plastic containers that have scratches or pits as these can potentially release more BPA when heated.

As a concerned consumer, it is important for you to stay on top of this research so that you know how to best protect you and your family. The FDA provides a Consumer Updates page and can even email you with recent consumer updates as well.

 


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