What is BPA, and why you should care about it.
BPA stands for bisphenol A. An industrial chemical that has been used in production of certain plastics and resins since the 1960s.
BPA is found in polycarbonate plastics and epoxy resins. Polycarbonate plastics are often used in containers that store food and beverages, such as water bottles. They may also be used in other consumer goods.
Epoxy resins are used to coat the inside of metal products, such as food cans, bottle tops and water supply lines. Some dental sealants and composites also contain BPA.
Some research has shown that BPA can seep into food or beverages from containers that are made with it. Exposure to BPA is a concern because of possible harmfull effects on the brain and prostate gland of fetuses, infants and children. It can also affect children's behavior. Additional research suggests a possible link between BPA and increased blood pressure.
How much of it is true vs myth? Let's take a look!
History of BPA
Bisphenol A was first discovered in 1891 by Russian chemist Aleksandr Dianin. Dianin's method for preparing bisphenol A from 1891 remains the most widely-known approach, though the method has been refined for industrial-scale synthesis.
It involves the catalysed condensation of a 2:1 mixture of phenol and acetone in the presence of concentrated hydrochloric acid or sulfuric acid. The reaction proceeds readily at room temperature producing a crude product containing a great variety of side products in a matter of hours. The overall equation is simple, with water as the only by-product.
In 1934 workers at I.G. Farbenindustrie, a German chemical and pharmaceutical conglomerate, reported the coupling of BPA and epichlorohydrin. Over the following decade, coatings and resins derived from similar materials were used by workers at DeTrey Freres in Switzerland and DeVoe and Raynolds in the US.
This early work underpinned the development of epoxy resins, which in turn lead to production of BPA. The utilization of BPA further expanded with discoveries at Bayer and General Electric on polycarbonate plastics.
In terms of the endocrine disruption controversy, the British biochemist Edward Charles Dodds tested BPA as an artificial estrogen in the early 1930s. He found BPA to be 1 / 37,000 as effective as estradiol. Dodds eventually developed a structurally similar compound, diethylstilbestrol (DES), which was used as a synthetic estrogen drug in women and animals until it was banned due to its risk of causing cancer; the ban on use of DES in humans came in 1971 and in animals, in 1979. BPA was never used as a drug.
As discussed earlier, Bisphenol A (BPA) is a chemical used to harden plastic. It is found in a number of consumer products, including hard plastic drinking containers, hard plastic baby bottles and drinking cups, and the linings of infant formula and food cans. In the United States, nearly everyone has measurable levels of BPA in their bodies.
In 2003, U.S. consumption was 856,000 tons, of which 75% was used to make polycarbonate plastic and 21% for epoxy resins. In the U.S., less than 5% of the BPA produced is used in food contact applications, but remains in the canned food industry and printing applications, such as sales receipts.
In 1997, adverse effects of low-dose BPA exposure in laboratory animals were first proposed. Modern studies began finding possible connections to health issues caused by exposure to BPA during pregnancy and during development. As of 2014, research and debates are ongoing as to whether BPA should be banned or not.
Endocrine disrupters are synthetic substances that, when introduced into the body, either imitate or block the effects of the body's natural hormones. Naturally-occurring hormones include estrogens, androgens (e.g. testosterone), thyroid hormone, and pancreatic hormones. Therefore, artificial interference with hormone actions prompts concerns about reproductive effects and developmental effects, the body's ability to regulate metabolism, and the body's ability to use insulin, among many other possible effects. In animal studies, BPA has been shown to affect estrogens.
BPA's ability to mimic the effects of natural estrogen derive from the similarity of phenol groups on both BPA and estradiol, which enable this synthetic molecule to trigger estrogenic pathways in the body. Typically phenol-containing molecules similar to BPA are known to exert weak estrogenic activities, thus it is also considered an endocrine disrupter (ED) and estrogenic chemical. Xenoestrogens is another category the chemical BPA fits under because of its capability to interrupt the network that regulates the signals which control the reproductive development in humans and animals.
Exposure to BPA is a concern because of possible harmfull effects on the brain and prostate gland of fetuses, infants and children. It can also affect children's behavior. Additional research suggests a possible link between BPA and increased blood pressure.
How are humans exposed?
Human exposure is primarily through eating food and drinking liquids that were in contact with BPA. BPA can leach from the plastic container or food can liner into foods and beverages. This seems to happen to a greater degree when the liquid is heated or the container is scratched and rough. BPA is absorbed readily when ingested, but the liver quickly metabolizes the chemical. It is excreted in the urine within 24 hours and does not accumulate in the body. In other words, if someone had a single exposure, it would be entirely gone from the body after a day. Repeated exposures are necessary to have measurable levels on a regular basis.
The majority of people in the United States have measurable quantities of BPA in their urine. In 2003-2004, the U.S. Centers for Disease Control and Prevention (CDC) assessed 2,517 US residents aged six and older. BPA was detected in the urine of 93 percent of samples.1 CDC notes that these data do not mean that adverse health effects occur; they are intended for use as a baseline for the general population.
There can be some environmental exposure, for example from industrial processes and recycling, but these exposures are not considered to be significant under usual circumstances.
In 2010, the U.S. Environmental Protection Agency reported that over one million pounds of BPA are released into the environment annually. BPA can be released into the environment by both pre-consumer and post-consumer leaching. Common routes of introduction from the pre-consumer perspective into the environment are directly from plastics, coat and staining manufacturers, foundries who use BPA in casting sand, or transport of BPA and BPA-containing products. Post-consumer BPA waste comes from effluent discharge from municipal wastewater treatment plants, irrigation pipes used in agriculture, ocean-borne plastic trash, indirect leaching from plastic, paper, and metal waste in landfills, and paper or material recycling companies. Despite a rapid soil and water half-life of 4.5 days, and an air half-life of less than one day, BPA's ubiquity makes it an important pollutant. BPA has a low rate of evaporation from water and soil, which presents issues, despite its biodegradability and low concern for bio-accumulation. BPA has low volatility in the atmosphere and a low vapor pressure between 5.00 and 5.32 Pascals. Aqueous solutions of BPA absorbs at wavelengths greater than 250 nm
There are differences of opinion among researchers, health care providers, and parents and consumers about how much weight to accord the many different types of research findings.
The chemical industry argues that BPA has been used in consumer products for more than fifty years, it has been approved for food applications by many developed countries, and that human health effects have not been documented.
Some scientists argue that there are too many differences among studies, and too many differences between humans and the animals studied, to draw conclusions. They note, for example, that rats metabolize BPA differently from humans and that infants, children, and adults metabolize BPA differently from each other. Some highlight the fact that hormones produced naturally in the body have different effects at high and low levels and that studies of BPA administered at high levels may not accurately reflect toxic effects of low-level exposure. They also note that comparing studies with different purposes, designs, subjects, amounts and routes of BPA exposure, and endpoints does not lead to convincing data.
Other scientists, along with some health care providers, parents, and consumers argue that the animal data are sufficiently compelling to act aggressively to limit human exposure. They note that the absence of documented effects does not mean that there are no effects, and further note that proving "no effect" is a very high standard, especially when discussing human health, and – more particularly – the health of children.
Bisphenol A (BPA) is a plastic found in some hard plastic (polycarbonate) water bottles, baby bottles, infant cups, and metal can linings, including the linings of some canned baby formula. It has been used since at least the 1960s but lately there have been conflicting stories in the media about the safety of BPA. Should you be concerned?
Some groups have stated that this chemical is harmful to humans, especially children. Others state that there is a long history of safe use and that concerns are exaggerated.
Is BPA harmful?
- In November 2006, the European Food Safety Authority concluded that studies of BPA in rodents did not demonstrate clearly that there was harm that could be reliably quantified.
- In August 2008, the U.S. Food and Drug Administration (FDA) reported that, based on currently available research, the amount of exposure to BPA from food sources was safe.
- In September 2008, the National Toxicology Program Center for the Evaluation of Risks to Human Reproduction, National Institutes of Health, issued a report based on very low-level exposures in laboratory animals. Based on these studies, the National Toxicology Program raised the need for further study to determine if BPA might affect the brain, behavior, and prostate gland in fetuses and young children.
- In the fall of 2009, FDA issued a review of studies of low-dose exposure to BPA and asked government scientists to evaluate this review document.
- In January 2010, the U.S. Centers for Disease Control and Prevention noted that almost everyone tested in the U.S. has some BPA in their urine, and that human health effects at the levels found are unknown.
- In January 2010, FDA announced that it is seeking additional research into possible human health effects and taking steps to decrease the amount of BPA that humans are exposed to.
- In March 2013, FDA's assessment was that "BPA is safe at the very low levels that occur in some foods."
Where does this leave the average consumer? In some cases, it's getting easier to avoid BPA, as manufacturers are discontinuing its use. Here are guidelines for people who are trying to avoid BPA.
- Baby bottles and sippy cups manufactured in the U.S. since 2012 are BPA-free by law.8 Most baby bottles manufactured between 2009 and 2012 were also BPA free. Contact the manufacturer if you're not sure about the older brands.
- Look for reusable water bottles labeled "BPA-free". More and more like this are coming on the market.
- Plastics marked with recycle codes 1, 2, 4, 5, and 6 are unlikely to contain BPA, according to FDA.
- Discard scratched baby bottles, infant feeding cups, and water bottles. Minute amounts of BPA might leak into the contents; in addition, damaged areas could provide a hiding place for germs.
- Canned baby formula may or may not have BPA in the lining. In fact, different lots from the same manufacturer may have differences in the BPA content (though very small amounts are involved). FDA believes that the benefits of consistent, complete nourishment for infants not being breast-fed outweigh any slight risk of as-yet undetermined health effects. Manufacturers are seeking non-BPA-containing liners that can withstand the heat used to process cans of formula.