Exposure to chemical found in plastics ‘hard to avoid’ in everyday life
4 February 2018
86 per cent of teenagers have traces of Bisphenol A (BPA), a chemical compound used to make plastics, in their body, an Engaged Research public engagement project in collaboration with the University of Exeter has found.
Measurable levels of BPA, an endocrine-disrupting chemical, were found in the urine of the vast majority of the 94 17-19 year olds tested, according to research at the University of Exeter led by Professor Lorna Harries, Associate Professor in Molecular Genetics, and Professor Tamara Galloway, Professor of Ecotoxicology.
They called for better labelling of packaging to enable consumers to choose BPA-free products.
The citizen-science project was carried out in a real-world setting to provide young people with first-hand experience of all aspects of scientific research.
Students designed, took part in and published the research study into whether changes in their lifestyle and diet could have an impact on BPA in their bodies. They found that chemical is so ubiquitous that trying to reduce exposure by avoiding food packaging and food likely to contain BPA has no measurable impact on exposure, according to research published in the BMJ Open journal.
The research, An engaged research study to assess the effect of a ‘real-world’ dietary intervention on urinary bisphenol A (BPA) levels in teenagers is the largest self-administered intervention study of exposure to BPA in unrelated individuals. Teenagers are thought to be one of the population demographics with the highest levels of exposure.
BPA passes relatively swiftly out of the body with a short half-life of around 6 hours, but measurable BPA was detected in 86% of the participating students, with an average level of 1.9ng/ml. This is similar to population exposure levels in other countries around the world, and reflects the exposure to BPA in the environment.
The study concluded:
“We found no evidence in this self-administered intervention study that it was possible to moderate BPA exposure by diet in a real-world setting. Our study participants indicated that they would be unlikely to sustain such as diet long term, due to the difficulty in identifying BPA free foods.”
BPA is an industrial chemical which has been used since the 1960s to make certain types of plastic. The chemical can be found in plastic containers and water bottles, till receipts, on the inside of cans and bottle tops and in plastic packaging and tubing. DVDs, CDs and sunglasses can also contain BPA though this is not a major route for exposure through skin.
BPA, a chemical with similarities to oestrogen, can get into the body through our diet. Highly-processed foods, or foods packaged in some plastics, can contain high levels of BPA. It is capable of causing changes to the expression of oestrogen-responsive genes, and the regulation of hormones, previous research by the Exeter team has found.[i] Endocrine disruptors are chemicals that may interfere with the body’s endocrine system. A wide range of substances, both natural and man-made, are thought to cause endocrine disruption. The EU Member State Committee (MSC) has said that Bisphenol A is an endocrine disruptor.[ii]
Leaching of BPA from products can increase with higher temperatures and with time and use, for example through repeated use of plastic water bottles if they contain BPA. The Exeter academics said consistent labelling of packaging would enable consumers to identify products containing BPA.
Professor Galloway said: “We found that a diet designed to reduce exposure to BPA, including avoiding fruit and vegetables packaged in plastic containers, tinned food, and meals designed to be reheated in a microwave in packaging containing BPA, had little impact on BPA levels in the body. Our students who followed the BPA-free diet reported that it would be difficult to follow it long term, because labelling of BPA products was inconsistent. They found it difficult to source and identify BPA-free foods.”
Professor Harries, Associate Professor of Molecular Genetics at the University of Exeter, said: “Our study shows that currently we do not have much of a choice about being exposed to BPA. We believe that much better labelling of products containing BPA is needed so people can make an informed choice”.
The teenagers’ urine was tested before they took part in the trial and afterwards to see if the diet made a measurable difference to levels of BPA in the urine. Overall, teenagers who spent a week following guidelines designed to reduce BPA exposure in their diet did not see a drop in exposure. However, some of those with the highest levels of BPA in their urine did show some reduction.
The students from schools in Devon followed strict guidelines that they had designed as part of the research team for a week which included avoiding plastic packaging which contains BPA, switching to stainless steel and glass food and drink storage containers, and avoiding tinned food. They were also asked to switch to ceramic or glass food containers before microwaving.
Professor Galloway said: “Exposure to the endocrine-disrupting chemical Bisphenol A is ubiquitous. There is growing evidence that exposure to endocrine-disrupting chemicals may be associated with adverse health outcomes. Measurable levels of BPA were present in the vast majority of our participants. They were unable to achieve a reduction in their urinary BPA levels over the 7-day trial period despite good compliance to supplied guidelines.”
Students who followed the BPA-free diet reported that it would be difficult to follow it long term, because labelling of BPA products was inconsistent and the difficulty of sourcing and identifying BPA-free foods.
Professor Harries, Associate Professor in Molecular Genetics at the University of Exeter, added: “BPA is a pervasive endocrine-disrupting chemical widely present in our food chain and our environment. Most people are exposed to BPA on a daily basis. In this study, our student researchers have discovered that at the present time, given current labelling laws, it is difficult to avoid exposure by altering our diet. In an ideal world, we would have a choice over what we put into our bodies. At the present time, since it is difficult to identify which foods and packaging contain BPA, it is not possible to make that choice. This study shows that it is possible to involve school students in real research. We wanted to give the students an authentic experience of what being a researcher is really like.”
This public engagement project was funded by a Wellcome public engagement award.
Articles | Exeter Medical School | University of Exeter
Lorna Harries | Exeter Medical School | University of Exeter
The press reported widely on the findings:
an exposure to plastics harm your health? It’s a question currently being explored by researchers after a recent study suggested that traces of a synthetic chemical called Bisphenol A (BPA) can be found in more than 80% of teenagers. BPA is added to plastic to create a special form called polycarbonate plastic, used in making robust, impact-resistant materials for everything from food and drink packaging to DVD cases and medical devices. First created in 1891, it has been used commercially since the 1950s and is now one of the most commonly produced chemicals in the world, with 3.6bn tonnes of BPA generated every year.
The problem is that BPA can be ingested or absorbed through skin contact, meaning that humans are regularly exposed through the chemical leaching out of packaging into food and drink – and over the past 20 years various studies have linked BPA to a variety of adverse health effects. The biggest concerns have been the impact on foetuses and young children, who have underdeveloped systems for detoxifying chemicals – the consequences being that the younger you are, the higher the levels of BPA in your body.
Once in the human body, BPA mimics the action of the hormone oestrogen and disrupts the endocrine system – the glands that produce hormones regulating, among other things, metabolism, growth, sexual function and sleep. Studies examining the effects of very high doses of BPA in mice have shown that this can cause problems with liver and kidney function, and mammary gland development. While these studies involve much higher doses than the general public would ever be exposed to, there are concerns that the levels of BPA that accumulate in infants can still have adverse developmental consequences, leading to neurobehavioural and immune system abnormalities.
As a result, in the US, the Food and Drug Administration has banned BPA use in baby bottles and infant feeding cups. However, in teenagers and adults, the exact health risk posed by persistent levels of BPA in our systems remains controversial. Most notably it has been linked to male infertility through decreasing sperm quality, but in addition a number of scientists believe that continuous BPA exposure, altering normal hormonal signalling in the body, may be a component in the development of a number of chronic diseases. One study in mice found a link between BPA exposure and an increased risk of type 2 diabetes and insulin resistance, while others have explored a potential relationship between BPA exposure and coronary artery disease due to potential alterations in cardiac function over a long period of time. Some have even suggested an association between BPA and breast cancer as, with only 10-15% of breast cancer cases linked to hereditary factors, chemical exposure may be among the environmental factors driving the remaining cases.
The problem is that it is hard to get concrete proof that BPA is definitively involved in many of these diseases. “Obviously it’s not ethically possible to experiment with humans, so most of the studies have been in test tubes or animals, and then scientists extrapolate from that what might be happening in humans,” says Tamara Galloway, a professor of ecotoxicology at the University of Exeter. “There have also been epidemiological studies where we measure the concentration of BPA in people’s bodies, look at what they’re suffering from, and then infer an association. But because you can’t establish a direct causal link, it’s hard to make strong conclusions, and that’s what causes the controversy.”
However, precautionary measures are still being taken. After a review of the scientific literature, and in light of the health uncertainties, the European Food Safety Authority saw enough to order a reduction in the tolerable daily intake that we’re allowed to be exposed to in food and drink packaging. In France, the national agency for food, environmental and occupational health has gone even further, completely banning the use of BPA in any packaging that comes into contact with food.
One of the problems is that, even with these regulations, it is actually extremely hard to avoid coming into contact with BPA as it’s simply everywhere, from plastic drinks bottles to the epoxy resins that line the cans of tinned food, to the ink on supermarket till receipts. “That ink can pass across your skin in small quantities,” Galloway says. “There are now studies looking at the extent of the exposure you can get from handling these receipts.” And of course, the amount of plastic waste disposal in the environment means that BPA leaches into rivers and soil, and eventually back into our bodies through food or drinking water in a cyclic process. So while the short half-life of BPA in adult humans means that it’s rapidly excreted in a matter of hours, because it’s so ubiquitous in our world, as many as 95% of us will always have traces of BPA in our body through continuous exposure.
Galloway believes there are certain steps we can take to limit our exposure – such as breastfeeding children or ensuring that any baby bottles that we purchase come with a BPA-free label.
“You can do things like buying unpackaged fruit and vegetables and avoiding heavily processed and packaged food,” she adds.
In addition, several studies have shown that reheating food in the microwave in plastic polycarbonate containers can speed the transfer of trace amounts of BPA on to the food. Scientists are hoping that publicity around the potential harmful consequences of BPA exposure will encourage more manufacturers to withdraw it from their products, enabling them to analyse whether this is having a notable effect on reducing BPA levels in the population.
“If you go to your average supermarket, you’ll find that a lot of food and drink packaging will have labels saying ‘BPA free’,” Galloway says. “And with regulations like plastic bag bans hopefully reducing the amount of plastic waste in the environment, it’ll be interesting to see if that’s reflected in population levels of exposure – whether they do start to come down.”
Darf Essen in geöffneten Konservendosen aufbewahrt werden? - Hungry for Science - derStandard.at › User
But in the United States, the Food and Drugs Administration says there's nothing to worry about:
Is BPA Safe? FDA Touts New Study Showing 'Minimal' Effects, but Experts Are Wary - Newsweek
BPA unlikely to be harmful, federal study shows - NBC News