Bisphenol A

What is Bisphenol A (BPA)?
Sources of BPA exposure
Reducing Exposure to BPA
MDH Action on BPA
Current Research on the Health Effects of Bisphenol A
For More Information on BPA Exposure and Health Effects

What is Bisphenol A (BPA)?

Bisphenol A (BPA) is a chemical commonly used in plastics, food cans, and thermal paper (like that used for some receipts). BPA is present in many consumer products and in the environment. Studies show that high levels of BPA harm laboratory animals and have potential to harm human health.

The likelihood that a person will be harmed by a chemical depends on exposure (the amount of the chemical that enters the body) and toxicity (the ways that the chemical acts once it is inside the body.) Health effects may also depend on when a person is exposed, and for how long. These factors, as they relate to BPA, are described below. 

Sources of BPA Exposure

Sources of BPA exposure have been well-studied. These studies estimate the different amounts of BPA that might be absorbed in to the body from different consumer products. In addition, monitoring of chemicals in the blood and urine of people tested across the country tells us about how much BPA we may be exposed to. (Fourth National Report on Human Exposure to Environmental Chemicals, CDC).

For most people, packaged food is the largest source of BPA exposure. Metal food cans and cardboard containers can be lined with resins made from BPA. The liners protect food from contamination, protect the container from corrosion, and extend the shelf life of foods and beverages. Some canned food producers have begun to switch to can linings made without BPA.

BPA exposures have been highest among infants and children, but this trend may be decreasing. BPA was once common in plastic baby bottles and products specifically for children. In recent years, the following bans have been put in place to reduce exposure to BPA for infants and children:

  • Minnesota and the US Food and Drug Administration (FDA) have banned the sale of infant and child bottles and cups containing BPA.
  • Minnesota has banned the use of BPA in children’s food containers.
  • The FDA has banned the use of BPA in infant formula packaging.

Human breast milk often contains low levels of BPA due to the mother’s exposure from canned food and other sources. MDH continues to recommend breastfeeding as the healthiest option for feeding infants. The numerous health benefits of breastfeeding appear to outweigh potential harm from exposure to environmental chemicals in breast milk (See Breastfeeding: Exposure to Environmental Toxins, CDC).

Small BPA exposures can occur from other sources.

  • BPA is used in some dental sealants and resins. The best available data tell us that exposure to BPA from these sealants is very low and only lasts for a short time after the sealants are applied.
  • BPA is common in thermal paper used in cash register receipts, and can transfer to the fingers. For most people, exposures from thermal paper are very low. If you handle paper receipts frequently (for example, at work), wash your hands often to reduce exposure.     

Exposure may also occur from your environment. BPA is commonly detected at low concentrations in both indoor and outdoor air, in surface water, and in house dust.

Reducing Exposure to BPA

  • Purchase food cans and containers labeled “BPA-Free.”
  • Switch to fresh or frozen foods when they are available.
  • Avoid microwaving plastic food containers.
  • Try to use glass, porcelain, or stainless steel containers, especially for hot foods and beverages.

A nursing mother can reduce her infant’s exposure by using the tips above to reduce her own exposure. MDH does not recommend that you stop breastfeeding, even if you are concerned about BPA. The numerous health benefits of breastfeeding appear to outweigh potential harm from exposure to environmental chemicals in breast milk.

MDH Action on BPA

Exposure to BPA is widespread, but research shows that the range of exposures for most people are not expected to cause harm. In order to continue to protect and maintain health, however, MDH has taken some action.

MDH developed health-based guidance values for BPA in drinking water (Bisphenol A Information Sheet). People drinking water at or below the guidance value will have little or no health effects from BPA in their drinking water.

MDH named BPA to the Priority Chemical list through the Toxic Free Kids program. Chemicals named to the Priority Chemical list exhibit hazardous health traits, are high-production volume chemicals, and are also found to have a presence in humans and/or the environment. More information can be found at the Toxic Free Kids website.

MDH continues to monitor new studies and available information. As more information becomes available, MDH may offer additional advice to the public.

Current Research on the Health Effects of Bisphenol A

BPA is one of many chemicals that can disrupt the endocrine system by acting like a hormone or changing the way hormones act. The endocrine system includes several glands (e.g., ovaries, testes, pituitary, thyroid, etc.) and hormones. Hormones regulate growth, development, metabolism, brain function, nervous system, sleep, mood, sexual development and sexual function. Chemicals that disrupt the endocrine system can have different effects depending on the stage of life when exposure occurs. For example, exposures to endocrine-active chemicals during pregnancy, infancy or puberty are of special concern. Chemicals without endocrine activity typically lead to increased toxicity with increasing exposure levels and have little or no effects at lower levels. Some endocrine-active chemicals, however, may not follow this typical pattern.

Studies in rodents show that high oral doses of BPA may affect:

  • fetal, infant and pubertal development,
  • male and female reproductive organs and functions, and
  • organs such as the liver, kidney and thyroid.

Many of the BPA studies designed to meet global regulatory requirements have reported effects in animals only at doses far higher than those most Minnesotans receive.

One of the main controversies in BPA research is whether BPA impacts the endocrine system or has other effects at lower doses than are typically considered safe by the majority of regulatory authorities worldwide. Some researchers have reported health effects at lower doses, but these studies have not always been reproducible by other researchers, have not used dosing methods appropriate for assessing human exposure, or have had other limitations in their study methods. To help resolve the low-dose question and fill data gaps, the U.S. Food and Drug Administration (FDA), the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program (NTP) established a research consortium known as CLARITY-BPA to link academic and guideline compliant research, described in "How is NIEHS/NTP Researching the Health Effects of BPA"

In 2010, NTP indicated “some concern” for effects on the brain, behavior and prostate gland in fetuses, infants and children at current exposures to BPA but also concluded that there were insufficient data from humans and only limited evidence from animals. Minimal or negligible concern was concluded for other potential reproductive and developmental effects. Since the time of the NTP report, some researchers have reported that BPA might cause cancer, metabolic disease (i.e., obesity, diabetes), alter mammary gland development, and impair behavioral development. However, available studies do not yet support these conclusions and the ongoing CLARITY-BPA consortium studies will try to answer many of these remaining questions.

As part of the ongoing CLARITY-BPA consortium studies, FDA researchers have not yet been able to find low-dose endocrine-related effects in rats exposed to BPA through multiple life stages (i.e., during pregnancy, infancy, and as adults). A longer-term, lifetime study in rats is ongoing and expected to be completed in 2016. (see also: Working Together: Research and Science-Based Regulation of BPA).

How BPA is processed and handled in the body is becoming better understood. Particularly important are some significant differences between rodents and non-human primates. Young rodents appear to be more sensitive than young non-human primates to effects of BPA because of different metabolic capabilities, resulting in much higher blood levels of BPA when exposed to similar oral doses. MDH is monitoring continued developments in BPA research, including the ongoing FDA chronic rat study and associated CLARITY-BPA consortium studies.

For More Information on BPA Exposure and Health Effects:

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Updated Wednesday, 23-Jul-2014 10:27:42 CDT