A new study has found a link between heart disease and a chemical found in the lining of canned beverages, plastic bottles, re-usable containers, and the blood and urine of 90 per cent of people. Three days after the study’s publication the US Food and Drug Administration outlined new guidelines on the chemical, bisphenol-A (BPA), which is banned from baby bottles in Canada and some US jurisdictions but is still unregulated in Europe.
The research, published in the scientific journal PlosOne on January 12, found that American men over 60 with the highest levels of BPA in their urine on average had a 45 per cent greater chance of developing cardiovascular disease than men with lower levels of the chemical.
This does not conclusively prove that BPA causes cardiovascular disease, says study author Dr. Tamara Galloway, Professor of Ecotoxicology at the University of Exeter, UK. The association could be influenced by other factors, such as a poor diet featuring large amounts of canned food, she said.
But the finding does add to more than 200 scientific studies that have linked the chemical to human health concerns, including diabetes, breast cancer, obesity, hyperactivity and behavioural problems, and early puberty. Of particular concern is the chemical’s potential to affect the development of infants and babies in the womb (it is also found in umbilical cord blood).
BPA is able to mimic the hormone estrogen (dubbed an “endocrine disruptor”) and numerous studies in lab animals have demonstrated effects at extremely low doses, such as changes to the development of mammary glands in mouse embryos exposed to levels equivalent to just 25 parts per trillion. The average level of BPA in the urine of people sampled in the newest study was 3.3 parts per billion.
Used to manufacture clear, polycarbonate plastic and the epoxy resins used in the lining of tin cans, BPA is found in many plastics that are labeled with the number seven (found in the triangular recycling symbol). It is used to make a wide variety of products including CDs, circuit boards, coffee makers, water cooler jugs, auto parts, sports equipment, cell phones, cameras, eyeglass lenses and medical equipment.
In 2008 Canada designated BPA “toxic” and became the first country to ban the sale and import of baby bottles containing it. The states of Connecticut and Massachussets have placed restrictions on the chemical, and several US senators are forwarding legislation to ban it from baby products. Many large brands and retailers such as Wal-Mart, Toys “R” Us, Playtex and Nalgene have pledged to phase out the chemical.
The newest study is particularly significant because “it is the first major epidemiological study to replicate an earlier finding – this brings a much higher level of confidence in the study’s validity,” says Professor Frederick vom Saal of the University of Missouri-Columbia. His own research has shown multiple effects on laboratory mice exposed to BPA, including developmental changes in the prostate glands, which he says suggest men exposed to the chemical before birth could be predisposed to develop prostate cancer later in life.
“It’s important to note that nobody claims any of the diseases BPA is related to are caused solely by this chemical, but that it could be an important contributing factor,” he says. Based on what we know, it is “lunacy” to allow BPA to be used in products that come into contact with food, he says.
The chemical poses more than just a risk to human health. “BPA is a huge environmental problem – it is estimated to contribute the highest level of estrogenicity released from landfills,” says Dr. Galloway.
Many other chemicals, such as phthalates (found in cosmetics, shampoos, soft plastics and clear plastic food wraps), flame retardants (used in many electronics), and other petrochemicals found in consumer products are also able to mimic hormones and can affect wildlife. BPA has been found to affect the development of snails, for example, at extremely low levels.
But the science isn’t all scary, says Dr. Galloway. BPA is rapidly broken down in the environment, unlike “persistent pollutants” like DDT, flame retardants and “non-stick” chemicals like Teflon, which will remain in the environment for decades. Children born today still carry PCBs in their blood, despite the fact that the chemical was broadly banned in the 1970s. On the other hand, BPA is broken down in the environment quickly.
Moreover, BPA is metabolised rapidly by the body compared to other chemicals, so people can quickly lower their blood levels. The newest study, based on a sample of the US population, shows a 30 per cent decline in average levels of the chemical in the US population since the last survey in 2003. “That’s really good news, and it happened without any legislation,” she comments, noting that public concern over the chemical could have led people to avoid canned food and drink and plastics known to contain BPA.
But many supposedly safe plastic products still contain the chemical. An analysis carried out by the government agency Health Canada in 2009 found that a number of baby bottle brands labeled “BPA-free” still contained trace amounts of the chemical. And a study commissioned by the Milwaukee-Wisconsin Journal Sentinel in 2008 found that BPA leaches into food from plastics not typically thought to contain BPA, including Nos 1, 2 and 5.
And even switching entirely to glass containers from plastic still leaves other routes for exposure, as Rick Smith, executive director of the Canadian advocacy group Environmental Defence discovered. For his book Slow Death by Rubber Duck, Smith experimented on himself by eating food microwaved in plastic containers, drinking canned pop and doing everything he could to elevate his own levels, which instantly shot up.
He then stripped everything suspect out of his diet and saw his BPA levels quickly drop – though not entirely. Clearly, he says, BPA was still able to suffuse his body through other known sources such as newspaper inks, grocery store receipts, recycled paper products and trace amounts in drinking water.
But BPA is something we can feel positive about, he says. ”If we ceased production of this chemicals tomorrow it would literally disappear from our bodies and from virtually every part of the environment – it would fizzle out.” Already chemists are finding new ways to make hard plastics with less (or no) BPA.
“There is absolutely no question in my mind that we will see this chemical disappear,” he says, adding that he is certain the Canadian government will bring in a broader ban in the next decade reaching beyond baby products. ”You would be hard pressed to think of any other single action that should be taken to protect human health than to ban this product from items that come into contact with food and drink.”
Smith believes the US will soon follow Canada’s example, but Professor Patricia Hunt of Washington State University, who has been studying BPA and its effects on lab animals for the past 15 years, isn’t so convinced. “I think it will be a lot more difficult here than in Canada – for one because there aren’t any manufacturers of the chemical on Canadian soil,” she says.
But the shift in public awareness of the chemical over the past 10 years has been “just amazing,” says Prof Hunt. “It’s parents in particular who have been demanding BPA-free products. That’s where change will come from: not from legislation, but from industry bowing to consumer demands.”
On Friday the FDA in the US announced its new position on the chemical, stating that “on the basis of results from recent studies using novel approaches to test for subtle effects [the FDA has] some concern about the potential effects of BPA on the brain, behavior, and prostate gland in fetuses, infants, and young children, [and will be conducting] in-depth studies to answer key questions and clarify uncertainties about the risks of BPA.” The agency has also ear marked $30 million to study the chemical for the next two years.
This is the first time the FDA has expressed concern over the safety of BPA. “This is huge,” says Prof vom Saal. “We finally have science overcoming politics in the US. Previously, under President Bush, the FDA behaved essentially like a public relations wing for the chemical industry.”
The American Chemistry Council, which represents companies that manufacture BPA, states that “consumer products made with BPA are safe for their intended uses and pose no known risks to human health.”
This position is unlikely to change soon, says consumer advocate Smith. “They are manning the barricades, and their game plan is clear: deny, deny, deny,” he says. “They are still fighting any increased regulation of BPA in any form. And based on the leaked minutes of their planning session last year, we know exactly how low they will stoop to maintain sales.”
While the chemical continues to cause controversy in America and Canada, where baby products are colourfully labeled “BPA-FREE”, it is considerably less visible in the UK and many other European countries.
“More attention is given by the media to our research on the other side of the Atlantic,” says Dr Galloway, who works in England. “There seems to be more of a public debate there.”