July 01 , 2008
Bisphenol A – a.k.a plastic #7
Amy Movius MD
There has been lot of attention given lately to bisphenol A, though perhaps not by that name. Bisphenol A, or BPA, is the component of plastic found in many water bottles and other products that is being scrutinized for adverse health effects. Bisphenol A is found in many substances; an estimated 2.3 billion pounds is produced yearly in the US, much of which goes into polycarbonate plastics and epoxy.
An extensive review of this compound and its effects was recently published by the National Toxicology Program, which is part of the National Institute of Health. This review considered numerous studies and incorporated the opinions of many different experts. There is no dispute that we are exposed to this chemical. In one study of over two thousand people 93% tested positive for the presence of BPA in the urine. BPA enters the body primarily through eating and drinking, as it can leech from containers containing plastic and/or epoxy, including baby bottles, water bottles, and the lining of tin cans. The amount that leaks into food/liquid increases with temperature. This is true regardless of the age of the container. Infants and small children tend to have higher levels because they have more exposure (drinking from baby bottles, mouthing plastic toys etc) but also because their bodies do not process it as quickly.
It is not clear if this exposure is harmful or not. Bisphenol A (BPA) is a compound similar in structure to estrogen, a sex hormone. Much of the focus regarding this compound has been directed toward reproductive and growth/development effects. Animal studies conclude that at high doses, it is indeed harmful. There are also many animal studies looking at lower doses, closer to those found in humans, some of which suggest some health effects, others which do not. The panel ultimately concluded that there was insufficient evidence to state whether or not BPA causes adverse developmental or reproductive effects in humans.
The expert panel expressed different levels of concern for BPA toxicity for different groups of people. The scale used for these adverse effects goes from “serious concern” to “concern” to “some concern” to “minimal concern” to “negligible concern”.
1. There is “some concern” that BPA exposure of fetuses, infants, and children can cause neural and behavioral effects.
2. There is “minimal concern” that BPA exposure of fetuses, infants and children can cause accelerations in puberty. There is also “minimal concern” that BPA has effects on the prostate in utero.
3. There is “negligible concern” that BPA exposure causes birth defects or reproductive problems in adults. This increases to “minimal” for highly exposed groups, such as those who are occupationally exposed.
BPA containing products are widely available and the expert panel does not make recommendations about behavior. If you do wish to reduce exposure, however, the following personal choices are recommended.
Don’t microwave polycarbonate plastic food containers, as bisphenol A leeches more quickly at warmer temperatures
Plastic containers that contain BPA usually have #7 on the bottom and may also have the initials “PC”.
Reduce use of canned foods
Use glass, porcelain or stainless steel containers, especially for hot food or liquids.
Use baby bottles that are BPA free.
Reference: NTP-CERHR Expert Panel Report on the Reproductive and Developmental Toxicity of Bisphenol A