Sources of Bisphenol A exposure
Current Research on Bisphenol A
MDH Action and Advice on Bisphenol A
U.S. Food and Drug Administration Statement on Bisphenol A
Legislative Action on Bisphenol A
Bisphenol A (BPA), a chemical widely used in plastics, has received increased attention recently due to increased public awareness of its presence in consumer products and in the environment as a whole. Concerns about BPA are based on two factors: the amount of the chemical to which a person may be exposed, and the effects of the chemical on human health during and after exposure.
BPA has been used in a wide variety of consumer products for several decades and continues to be manufactured in large quantities around the world. Because of this, almost everyone is exposed to it to some degree. BPA exposure may occur through the consumption of food and water that have had sustained contact with packaging materials made from BPA. These packaging materials include rigid plastic bottles made of polycarbonate plastic containing BPA, and metal cans, which are often lined with resins made from BPA. Many plastic baby bottles contain BPA, and special care should be taken when using these bottles to mimimize transfer of BPA to the bottle contents. Exposure may also occur from the environment; BPA is commonly detected at low concentrations in both indoor and outdoor air, in surface water, and in house dust. BPA is also commonly found in resins used as dental sealants. The 2007 and 2008 NTP reports on BPA (see links below) do not consider this to be a significant route of exposure because studies have demonstrated that detectable levels of BPA in the body only occur within an hour after treatment; this exposure is therefore very low compared to long-term exposures from food and water containers and the environment as a whole. Other studies have detected BPA in the saliva of patients with dental sealants, but not in the patients' blood serum. Limited data indicate that BPA is not found at detectable levels in public drinking water supplies, and the half-life of the chemical is short (on the order of a few days.) Human breast milk often contains detectable levels of BPA due to maternal exposure. Despite this, MDH does not recommend that mothers of infants avoid breastfeeding out of concern for BPA exposure; the numerous health benefits of breastfeeding outweigh any potential exposure to BPA from breast milk.
Two reports on small groups of people have highlighted the extent of the general public’s exposure to BPA and other chemicals:
Is It In Us? Toxic Trespass, Regulatory Failure & Opportunities for Action
BPA exposure has also been addressed by the Centers for Disease Control’s (CDC’s) National Health and Nutrition Examination Survey (NHANES). NHANES is a large-scale, ongoing survey of a wide range of health parameters measured in a large number of people throughout the United States. Data from the survey are often used by MDH in its evaluation of environmental hazards and risks. A few recent studies have evaluated BPA intake using data from NHANES:
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The National Toxicology Program (NTP), a branch of the U.S. Department of Health and Human Services, has completed a thorough investigation of BPA, including a review of current research into the chemical’s toxicity and the ways in which human beings can be exposed. In November of 2007, NTP issued its Expert Panel Report, which includes a description of health effects resulting from exposure. The summary document indicates levels of concern-- "some concern," minimal concern," or "negligible concern"-- for several combinations of toxic effects and affected populations. For pregnant women and fetuses, the panel expressed some concern for neural and behavioral effects to the fetus, minimal concern for prostate effects and accelerations in puberty, and negligible concern for birth defects and malformations. For infants and children, the panel expressed some concern for neural and behavioral effects and minimal concern for accelerations in puberty. For adults, the panel expressed negligible concern for reproductive effects in the general population, but elevated the concern level to "minimal" for highly exposed populations, such as individuals who are routinely exposed to high levels of BPA in the workplace.
The 2007 Expert Panel report was followed by a briefing document intended to inform the public on the results of NTP’s review of BPA. This brief, issued in draft form in April of 2008, reclassified some of the expert panel’s conclusions as to the level of concern for some health effects. Concerns for effects on prostate and mammary glands and for accelerated onset of puberty were upgraded from “minimal concern” to “some concern.” While the brief acknowledges the limitations of the animal studies cited in the expert panel report, it concludes that “the possibility that BPA may alter human development cannot be dismissed,” based on observations of effects in animals at levels of exposure similar to those observed in humans.
One of the principal controversies in BPA research is the question of whether BPA is toxic at very low doses. Many of the traditionally-designed studies investigating BPA toxicity have used doses far higher than those encountered by the general public. Some researchers have reported health effects at lower doses, but there are concerns that these studies have not always been reproducible by other researchers, or have not used dosing methods appropriate for assessing human exposure, or have not fully disclosed their methods. To help resolve the low-dose question, the U.S. Food and Drug Administration (FDA) and the National Institute of Environmental Health Sciences (NIEHS) have been working together on several new studies of the effects of BPA at low doses. Much of the new research has been funded through the American Recovery and Reinvestment Act of 2009 (commonly known as the "2009 Economic Stimulus").
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At the present time, MDH recommends that plastic food containers, including baby bottles, be treated with special care to avoid the possibility, however remote, that significant quantities of BPA could be transferred from the plastic to the bottle contents.
Overall, current research indicates that BPA exposure carries a low, but nonzero, health risk. Studies indicating health effects in laboratory animals are cause for some concern, but carry some uncertainty due to the dosing method (injection vs. ingestion) and differences in the way laboratory animals and humans metabolize the chemical.
MDH is continually monitoring current research on BPA and may offer additional advice to the public if sufficient data become available.
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In January of 2010, FDA issued new recommendations on the use of products containing BPA. The new statement referred to past reviews by FDA that had judged products containing BPA to be safe. However, the statement also acknowledged that newer studies have reported “subtle effects” at low doses.
The FDA statement makes recommendations for reducing infants’ exposure to BPA. These recommendations are similar to those provided by MDH: discard worn or scratched bottles, and do not overheat bottles. Like MDH, FDA encourages breastfeeding whenever possible. FDA notes that BPA has been detected in canned liquid infant formula, but states that the proven nutritional benefits of formula are greater than any potential risk from BPA exposure. BPA is not typically detected in powdered infant formula.
In light of recent public concern about BPA, FDA is considering changing the way in which manufacturers of food or food packaging are required to report their use of BPA to FDA. BPA is currently regulated as an approved food additive. This allows the chemical to be used in food and food packaging with no requirement to notify FDA. If BPA were regulated as a food contact substance rather than as a food additive, it would be subject to a newer regulation that requires manufacturers to report on how the chemical is used, and in what quantity. FDA also has the authority to require manufacturers to submit safety and exposure data for food contact substances. Given the concern about BPA exposure, FDA is searching for a way to regulate BPA as a food contact substance, and in the meantime is encouraging manufacturers to provide notifications voluntarily.
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In May of 2009, the Minnesota Legislature passed by a strong margin a bill to ban the sale of certain children’s products containing BPA. Governor Pawlenty signed the bill into law on May 7, 2009. The text of the bill and the record of the House and Senate votes are available at the Office of the Revisor of Statutes. The ban affects only bottles and cups intended for use by infants and children under three years of age. The ban is a precautionary measure that reflects the uncertainty about the effects of BPA at low doses, combined with increasing availability of alternative products in the marketplace. For more information on the new law, refer to MDH’s Bisphenol A Law page.
The narrow scope of this law means that other sources of BPA exposure, such as canned foods and any plastic products not covered by the law, will still be present. For information on how to minimize your (or your child’s) exposure to BPA, refer to MDH’s page describing chemicals of special concern to children’s health.
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