What is bisphenol A? Bisphenol A (BPA) is a chemical produced in large quantities for use mainly in the production of polycarbonate plastics and epoxy resins.
Polycarbonate plastics have many applications including use in certain food and drink packaging, e.g., water and infant bottles, compact discs, impact-resistant safety equipment, and medical devices. Epoxy resins are used as lacquers to coat metal products such as food cans, bottle tops, and water supply pipes. Some polymers used in dental sealants or composites contain bisphenol A-derived materials. In 2004, the estimated production of bisphenol A in the United States was approximately 2.3 billion pounds, most of which was used in polycarbonate plastics and resins.
How does bisphenol A get in the body?
The primary source of exposure to bisphenol A for most people is through the diet. While air, dust, and water (including skin contact during bathing and swimming) are other possible sources of exposure, bisphenol A in food and beverages accounts for most daily human exposure. Bisphenol A can migrate into food from food and beverage containers with internal epoxy resin coatings and from consumer products such as polycarbonate tableware, food containers, water bottles, and baby bottles. The degree to which bisphenol A leaches from polycarbonate bottles into liquid may depend more on the temperature of the liquid or bottle, than the age of the container. Bisphenol A can also be found in breast milk.
Has anyone measured the amount of bisphenol A in humans? If so, who, and what are they finding?
Biomonitoring studies show that human exposure to bisphenol A is widespread. The 2003-2004 National Health and Nutrition Examination Survey (NHANES III) conducted by the Centers for Disease Control and Prevention (CDC) found detectable levels of bisphenol A in 93% of 2517 urine samples from people six years and older. The CDC NHANES data are considered representative of exposures in the United States.
Can bisphenol A affect human development or reproduction?
Possibly. Although there is no direct evidence that exposure of people to bisphenol A adversely affects reproduction or development, studies with laboratory rodents show that exposure to high dose levels of bisphenol A during pregnancy and/or lactation can reduce survival, birth weight, and growth of offspring early in life, and delay the onset of puberty in males and females. Recognizing the lack of data on the effects of bisphenol A in humans and despite the limitations in the evidence for "low" dose effects in laboratory animals, the possibility that bisphenol A may impact human development cannot be dismissed. More research is needed.
What can I do to prevent exposure to bisphenol A?
If you are concerned, you can make personal choices to reduce exposure:
- Don’t microwave polycarbonate plastic food containers. Polycarbonate is strong and durable, but over time it may break down from over use at high temperatures.
- Polycarbonate containers that contain BPA usually have a #7 on the bottom (http://www.recyclenow.org/r_plastics.html)
- Reduce your use of canned foods.
- When possible, opt for glass, porcelain or stainless steel containers, particularly for hot food or liquids.
- Use baby bottles that are BPA free.
