Scientists and NGOs concerned about the health impacts of bisphenol A

PRESS RELEASE, 23rd JUNE 2010

An unprecedented 60 scientists and international environment, health and women’s organisations from around the globe have jointly written to the European Food Safety Authority (EFSA) stating that

“action is necessary to reduce the levels of Bisphenol-A (BPA) exposure, particularly in groups at highest risk, namely young infants and pregnant mothers.”

[Quotes from some of the participating scientists and NGOs can be found towards the end of this release.]

In total, 41 NGOs and 19 scientists from 15 countries from across the globe (including 9 from the UK) have signed the letter. The letter comes on the eve of a new scientific opinion to be released by the EFSA on the safety of Bisphenol A in food contact materials expected in early July 2010. EFSA was requested by the European Commission to assess the latest science on Bisphenol A, and if necessary, to update the existing Tolerable Daily Intake (TDI) (a specific amount in food or drinking water that can be ingested (orally) over a lifetime without an appreciable health risk).

Bisphenol A is a mass produced chemical used in the manufacture of polycarbonate plastics that are clear and nearly shatter-proof. It can be found in plastics used for food and beverages, such as baby bottles, sports water bottles, as an epoxy resin in canned food and drinks, plastic food storage containers, tableware and in other products, including dental sealants, and has been found to leach into food and drink.

There have been long standing concerns about the health impacts of bisphenol A, due to scientific studies that have shown it has hormone disrupting effects at extremely low levels of exposure. Human bio-monitoring studies have shown that the vast majority of people in developed countries are exposed to Bisphenol-A.

EFSA’s previous opinions in 2007 and 2008 predominantly relied upon a handful of industry backed scientific papers that have expressed no concerns about our levels of BPA exposure. The letter from scientists and NGOs highlights scientific criticism in academic journals regarding these papers as compared to the “several hundred peer reviewed scientific papers have been published that have highlighted potential adverse health effects associated with BPA exposures”

The letter also draws attention to some of the new studies which have raised risks of exposure relating to a potential increased likelihood of developing ‘diabetes’, ‘developmental programming’ and ‘breast cancer’. Bisphenol A exposure at environmentally relevant levels commonly found in the environment in developed countries has also been repeatedly linked by independent university – based scientists to a number of other serious chronic health conditions.

Despite EFSA’s pivotal position in setting chemical food safety levels across the EU, Sweden and Germany have become the third and fourth most recent EU member states, alongside France and Denmark, to take action ahead of the EFSA review.

Andreas Carlgren, Sweden’s Environment Minister stated, on 11th May 2010, that

“If the EU will not quickly forbid the hormone disrupting substance bisphenol in baby-bottles Sweden will precede with a national prohibition.”

The President of the German Federal Environment Agency on the 9th June also broke from EFSA policy by issuing new guidance calling on

“manufacturers, importers and users of bisphenol A to use alternative substances that pose less risk to human health and the environment in all areas of use that significantly contribute to exposure”.

Regulators in Canada and the USA have already taken action to limit BPA exposure, for example in its use in baby bottles. As yet there has been no similar action at the European Union level.

A number of EU member states continue to back a common approach across the EU on bisphenol A. Tim Smith, the head of the UK Food Standards Agency, declared in an internal FSA report on the 12th May, 2010 that he ‘considers it important to have an agreed position across the EU’ and that the FSA will only ‘revise our position in line with it the EFSA Review if it is considered necessary’, despite the action that is being taken elsewhere across the EU.

The EFSA have already delayed publication of its review, as explained on its website:

To give the European Commission an up-to-date overview of the safety of BPA, EFSA will now deliver a scientific opinion in early July rather than end of May. This is due to the need for the Panel to consider hundreds of studies in its review and analysis of the most recent scientific literature.

The letter from scientists and organisations opens by ‘welcoming this announcement’ issued at the 11th hour that EFSA has finally agreed to examine hundreds of non-industry backed scientific papers.

The letter was drafted by Breast Cancer UK and Prof. Fredrick vom Saal, Curators Professor of Biological Sciences, University of Missouri-Columbia who has been awarded by his peers for his work on Bisphenol-A and is a recognised leader in this field. The effort was also coordinated by the Brussels based Health and Environment Alliance (HEAL).

Prof. vom Saal stated in response to the publication of the letter that:

“At the heart of the debate over BPA lies an outdated set of guidelines used by regulatory agencies that are based on approaches to evaluating the safety of chemicals established over 50 years ago. Thus, 21st century research approaches have provided overwhelming scientific evidence of harm in hundreds of published reports, but these findings are being rejected for consideration because they do not conform to the outdated testing guidelines.

“This has left regulatory agencies to rely entirely on industry-funded research that used ‘approved’ testing methods that are crude and insensitive, and it is not surprising that 100% of these industry-funded studies conclude that BPA causes no harm.

“The only rational path for European regulators is to take decisive action to reduce human exposure to BPA. The overwhelming nature of the total scientific evidence mandates this as a priority.”

Clare Dimmer, Chair of Trustees Breast Cancer UK and former breast cancer patient stated:

“Breast cancer is the most common cancer across Europe and has been increasing rapidly regardless of the costly and expensive efforts made by Governments to improve screening, treatment, and increase research. It must now be time that regulators act on the science and begin to take a precautionary approach to hazardous chemicals like bisphenol-A found in our everyday products.”

Lisette van Vliet, Ph.D. the Toxics Policy Advisor at HEAL said:

“It is high time that EFSA caught up to the overwhelming science showing genuine reasons for concern about our daily exposure to BPA.”

Participating scientists and organisations were given the opportunity to provide a quote for this press release; those that responded have been included below. This does not preclude participating organisations providing their own releases, supporting statements and additional comments.

Prof. Andrew Watterson, Occupational and Environmental Health Research Group, University of Stirling, said:

“It’s worrying, considering the weight of the scientific evidence, that strong action to reduce human exposure is yet to be taken. Hundreds of academic studies have explicitly raised the risks of developmental harm to foetuses and young children from exposure to BPA and this should dictate a strong precautionary policy response from European regulators. If this is not forthcoming, the UK Government must intervene as other European countries are already doing so.”

Daniela Hoffmann, Chemicals Expert, GLOBAL 2000/Friends of the Earth Austria:

“EFSA has to finally acknowledge the overwhelming scientific evidence concerning the risk BPA poses to human health.”

Sarah Häuser, Chemicals Expert BUND / Friends of the Earth Germany:

“The existing Tolerable Daily Intake for BPA does not protect human health. In animal experiments and biomonitoring studies, BPA doses much smaller than those estimated as being safe by EFSA were linked to chronic conditions health damages like diabetes and cardiovascular diseases. It’s time to take action now.”

For further information please contact:

Hratche Koundarjian, Campaign Manager, Breast Cancer UK, Charity No: 1088047, T: 07905 911 039, E: hratche@breastcanceruk.org.uk, W: www.breastcanceruk.org.uk / www.nomorebpa.org.uk

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Letter and Signatories:

Prof. Klaus-Dieter Jany, Chair of the CEF Panel

European Food Safety Authority

Largo N. Palli 5/A, 43121 Parma, Italy

23rd June 2010

Dear Prof. Jany,

We are writing to welcome the announcement on the European Food Safety Authority (EFSA) website that the CEF panel will be considering ‘hundreds of studies in its review and analysis of the most recent scientific literature’ in its review of the TDI of bisphenol-A in food contact products.

Over the last decade and a half, a substantive body amounting to several hundred peer reviewed scientific papers, have been published that have highlighted potential adverse health effects associated with BPA exposures, at internal doses relevant to levels of biologically active BPA found in humans.

As a March 2010 Review (Vandenberg et al) of 80 bio-monitoring studies of BPA in Environmental Health Perspectives makes clear;

‘The two toxicokinetic studies performed to date, which suggest that human exposure is negligible, have significant flaws and are therefore not reliable for risk assessment purposes.’

However, in its prior risk assessments of BPA, EFSA only relied on a small number of studies rather than the much larger number that the United States Food and Drug Administration recently recognised as valid and of high utility in its risk assessment of BPA, and which led the FDA to express concern about the health hazards posed by BPA.

Only a tiny minority of studies have articulated that BPA exposure is completely safe, and many of these research papers have been criticised in academic commentaries and responses as having serious flaws, but it is these few flawed studies that EFSA previously relied on to declare BPA safe.

For example, a letter co-authored by 24 scientists published in the February 2010 edition of Toxicological Sciences states;

‘Publishing studies that conclude no harm in response to low doses of endocrine disrupting chemicals, when the studies did not include a positive control (Tyl et al., 2002), included inappropriate doses of positive controls (Ryan et al., 2009; Tyl et al., 2008), or included positive controls that showed no effect (Cagen et al., 1999), is inappropriate in peer-reviewed journals (Myers et al., 2009a,b; vom Saal and Welshons, 2006). Such studies violate basic principles of study design.’

Many scientific studies are now calling into question the safety of BPA. For example, a recent study has highlighted that BPA may contribute to metabolic disorders relevant to glucose homeostasis, and suggests that BPA may be a risk factor for diabetes (Alonso-Magdalena et al., 2010). Moreover, experiments at Yale university report that BPA may induce altered developmental programming (Bromer et al.,2010), and Doherty et al (2010) of Yale university have published a study which raises the concern about epigenetic effects of BPA on the regulation of the mammary gland, with potential implications for breast cancer risk. Endometriosis is also a concern as work by Signorile et al (2010) highlights that pre-natal exposure of mice to bisphenol-A causes an endometriosis-like response in female offspring.

It is therefore our opinion that any objective and comprehensive review of the scientific literature will lead to the conclusion that action is necessary to reduce the levels of BPA exposure, particularly in groups at highest risk, namely young infants and pregnant mothers.

There are an increasing number of countries that are either already committed to this course of action, or have signalled that they will soon be undertaking similar measures.

We share the concerns of these Governments and regulators and believe that reducing BPA exposure to these groups is both scientifically sound and in the best interest of public health.

As such, we call on you as the Chair of the CEF panel and the CEF Committee Members in their ongoing review to include all relevant studies, including bio-monitoring studies, and based on that evidence we conclude that there is a strong scientific mandate for action.

Yours sincerely,

1. Benson Akingbemi, Associate Professor, Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, USA.
2. Prof. Dr. Ibrahim Chahoud, Institute of Clinical Pharmacology and Toxicology, Dept. of Toxicology, Charité – Universitätsmedizin Berlin
3. André Cicolella, Dipl Eng chemist-toxicologist.
4. Prof. Patricia Hunt, Meyer Distinguished Professor, School of Molecular Biosciences, Washington State University
5. Prof. Maricel V. Maffini. Ph.D. Research Assistant Professor. Department of Anatomy and Cellular Biology, Tufts University School of Medicine
6. Jane Muncke, Ph.D, Environmental Toxicologist, Emhart Glass SA, Switzerland.
7. John Peterson Myers, Ph.D., Chief Scientist, Environmental Health Sciences, Charlottesville VA.
8. Angel Nadal, PhD, Professor of Physiology, Instituto de Bioingeniería and CIBERDEM, Universidad Miguel Hernández de Elche, Spain.
9. Dr John Newby, Medical Information Scientist for the Cancer Prevention Society and Former Member of the Developmental Toxico-Pathology Research Group, Department of Human Anatomy & Cell Biology, Faculty of Medicine, University of Liverpool.
10. Prof. Jörg Oehlmann, Goethe University Frankfurt am Main, Institute for Ecology, Evolution and Diversity.
11. Prof. Gail S. Prins, PhD, Professor of Physiology, Department of Urology, University of Illinois at Chicago.
12. Prof. Fredrick vom Saal, Curators Professor of Biological Sciences, University of Missouri-Columbia.
13. Prof. Pietro Giulio Signorile, President of the Italian Endometriosis Foundation.
14. Prof. Ana M Soto, MD, Department of Anatomy and Cell Biology, Tufts University, School of Medicine.
15. Prof. Hugh S. Taylor, M.D., Professor of Molecular, Cellular and Developmental Biology, Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University.
16. Laura N. Vandenberg, PhD, Postdoctoral Fellow, Center for Regenerative and Developmental Biology, Tufts University.
17. Prof. Cheryl S. Watson, PhD, Professor, Biochemistry & Molecular Biology Dept. University of Texas, Medical Branch, Galveston.
18. Prof. Andrew Watterson, Occupational and Environmental Health Research Group, University of Stirling.
19. Prof. R. Thomas Zoeller, Biology Department, Morrill Science Center, University of Massachusetts.

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1. Action for Breast Cancer, Malta
2. Alliance for Cancer Prevention, UK
3. Arnika, Czech Republic
4. Association for Environmental and Chronic Toxic Injury, Italy
5. Austrian section of ISDE (International Society of Doctors for the Environment), Austria
6. Breast Cancer Fund, USA
7. Breast Cancer UK, UK
8. BUND / Friends of the Earth Germany, Germany
9. Cancer Prevention and Education Society, UK
10. ChemSec –International Chemical Secretariat, International
11. CHEM Trust, UK
12. Chemical Sensitivity Network, Germany
13. Clean Air Action Group, Hungary
14. Comité pour le Développement Durable en Santé, France
15. Danish Consumer Council, Denmark
16. The Danish Ecological Council, Denmark
17. Eco-Accord Program on Chemical Safety, Eastern Europe, Caucasus and Central Asia
18. EcoAid, Germany
19. Ecologistas en Acción, Spain
20. Environmental Health Fund, USA
21. Environment Illinois, USA
22. European Environmental Bureau, EU
23. Finnish Association for Nature Conservation, Finland
24. Friends of the Earth Spain, Spain
25. Global 2000 / Friends of the Earth Austria, Austria
26. Health and Environmental Network, Europe
27. Health Care Without Harm, International
28. Indiana Toxics Action, USA
29. Instituto Sindical de Trabajo Ambiente y Salud, Spain
30. The Irish Doctors’ Environmental Association, Ireland
31. Italian Endometriosis Foundation, Italy
32. Plastic Planet, Austria
33. Rachel’s Friends Breast Cancer Coalition, USA
34. Réseau Environnement Santé, France
35. Society for Sustainable Living, Czech Republic
36. Unison, UK
37. VHUE e.V., Germany
38. Women in Europe for a Common Future, Europe
39. Women’s Environmental Network, Scotland
40. Women’s Voices for the Earth, USA
41. WWF European Policy Office, Europe

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References

• Vandenberg LN, Chauhoud I, Heindel JJ, Padmanabhan V, Paumgartten FJ, Schoenfelder G 2010. Urinary, Circulating and Tissue Biomonitoring Studies Indicate Widespread Exposure to Bisphenol A. Environ Health Perspect :-. doi:10.1289/ehp.0901716
• vom Saal FS, Akingbemi BT, Belcher SM, Crain DA, Crews D, Guidice LC, Hunt PA, Leranth C, Myers JP, Nadal A, Olea N, Padmanabhana V, Rosenfeld CS, Schneyer A, Schoenfelder G, Sonnenschein C, Soto AM, Stahlhut RW, Swan SH, Vandenberg LN, Wang H, Watson CS, Welshons WV and Zoeller RT. 2010. Flawed Experimental Design Reveals the Need for Guidelines Requiring Appropriate Positive Controls in Endocrine Disruption Research. Toxicological Sciences 2010 115(2):612-613; doi:10.1093/toxsci/kfq048
• Alonso-Magdalena P, Vieira E, Soriano S, Menes L, Burks D, Quesada I, et al. 2010. Bisphenol-A Exposure during Pregnancy Disrupts Glucose Homeostasis in Mothers and Adult Male Offspring. Environ Health Perspect :-. doi:10.1289/ehp.1001993
• Bromer JG, Zhou Y, Taylor MB, Doherty L, Taylor HS. Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response. FASEB J. 2010 Feb 24. [Epub ahead of print] PubMed PMID: 20181937.
• Doherty L, Bromer JG, Zhou Y, Aldad TS and Taylor HS. In Utero Exposure to Diethylstilbestrol (DES) or Bisphenol-A (BPA) Increases EZH2 Expression in the Mammary Gland: An Epigenetic Mechanism Linking Endocrine Disruptors to Breast Cancer. Hormones and Cancer. DOI: 10.1007/s12672-010-0015-9.
• Signorile PG, Spugnini EP, Mita L, Mellone P, D’Avino A, Bianco M, Diano N, Caputo L, Rea F, Viceconte R, Portaccio M, Viggiano E, Citro G, Pierantoni R, Sica V, Vincenzi B, Damiano G. Mita DG, Baldi F and Baldi A. Pre-natal exposure of mice to bisphenol A elicits an endometriosis-like phenotype in female offspring. General and Comparative Endocrinology. doi:10.1016/j.ygcen.2010.03.030.

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German Translation by CSN:

60 Wissenschaftler und NGOs appellieren an EFSA

Yale scientists show how bisphenol A induces epigenetic changes in pregnant mice that cause hormonal imbalance in the later life of female progeny

Here’s more evidence that “safe” plastics are not as safe as once presumed: New research published online in The FASEB Journal suggests that exposure to Bisphenol A (BPA) during pregnancy leads to epigenetic changes that may cause permanent reproduction problems for female offspring. BPA, a common component of plastics used to contain food, is a type of estrogen that is ubiquitous in the environment.

“Exposure to BPA may be harmful during pregnancy; this exposure may permanently affect the fetus,” said Hugh S. Taylor, Ph.D., co-author of the study from Yale University School of Medicine in New Haven, Connecticut. “We need to better identify the effects of environmental contaminants on not just crude measures such as birth defects, but also their effect in causing more subtle developmental errors.”

Taylor and colleagues made this discovery by exposing fetal mice to BPA during pregnancy and examining gene expression and DNA in the uteruses of female fetuses. Results showed that BPA exposure permanently affected the uterus by decreasing regulation of gene expression. These epigenetic changes caused the mice to over-respond to estrogen throughout adulthood, long after the BPA exposure. This suggests that early exposure to BPA genetically “programmed” the uterus to be hyper-responsive to estrogen. Extreme estrogen sensitivity can lead to fertility problems, advanced puberty, altered mammary development and reproductive function, as well as a variety of hormone-related cancers. BPA has been widely used in plastics and other materials. Examples include use in water bottles, baby bottles, epoxy resins used to coat food cans, and dental sealants.

“The BPA baby bottle scare may be only the tip of the iceberg.” said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. “Remember how diethylstilbestrol (DES) caused birth defects and cancers in young women whose mothers were given such hormones during pregnancy. We’d better watch out for BPA, which seems to carry similar epigenetic risks across the generations. ”

Author: FASEB* – Federation of American Societies for Experimental Biology, Why BPA leached from ‘safe’ plastics may damage health of female offspring, 25-Feb-2010.

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* FASEB comprises 23 societies with more than 90,000 members, making it the largest coalition of biomedical research associations in the United States

4-n-Nonylphenol and bisphenol A are endocrine disrupting chemicals that are mainly detoxified through glucuronidation. A factor that may modulate their glucuronidation rates is co-exposure to pharmaceuticals.

This study aimed to identify and characterize the potential metabolic interactions between 14 drugs and these two endocrine disruptors. Nonylphenol and bisphenol A were co-incubated in freshly isolated rat hepatocytes with, drugs at a high concentration.

Statistically significant metabolic inhibition of bisphenol A and nonylphenol biotransformation was observed with nine drugs (>50% inhibition by naproxen, salicylic acid, carbamazepine and mefenamic acid). Inhibition assays of UGT activity in rat liver microsomes revealed: 1) competitive inhibition by naproxen (K(i)(app) = 848.3 muM) and carbamazepine (K(i)(app) = 1023.1 muM), 2) no inhibition by salicylic acid suggesting another mechanism of inhibition.

Detoxification of nonylphenol and bisphenol A was shown to be impaired by excessive concentrations of many drugs and health risk assessment should therefore address this issue.

Reference: Verner MA, Magher T, Haddad S., High concentrations of commonly used drugs can inhibit the in vitro glucuronidation of bisphenol A and nonylphenol in rats, Xenobiotica. 2009 Nov 16.

If it hadn’t been for the Big Macs that Joannie ate pretty much three times a week, she wouldn’t have gotten fat.  If she hadn’t been exposed while in her mother’s womb to chemicals x, y and z, Joannie wouldn’t have had the propensity to get fat.  And if Joannie’s mom had eaten more sensibly, both waistlines would be slimmer.

Fat people most likely are programmed to become fat before taking their first sip of milk.

Today’s news is, that pesticides are among the chemicals responsible for this reprogramming.

Two of three U.S. adults are now classified as overweight.  Type II diabetes has increased in like measure over the same decades, and so has heart disease.  This is not a coincidence.  These illnesses share common characteristics: they are triggered while in the womb by exposure to the same kinds of chemicals and the outcomes show up in adulthood.  Scientists now call this pattern “the fetal origins of adult diseases”.

The most likely culprits are chemicals now grouped together under the rubric “endocrine disrupters.” It’s been known for about two decades, though disputed by the manufacturers, that these chemicals alter the normal signaling pathways of hormones.  Think of Bisphenol A (BPA), right now the nation’s most celebrated endocrine disruptor.

Pesticides, though not specifically thought of as endocrine disruptors nor regulated as such, can similarly knock normal development off track.  Research has just found that a family of pesticides among the most widely used in the world is connected to these three adult illnesses.  This is the family of organophosphates, concocted from petroleum with an addition of phosphoric acid.

When lab rats are exposed to these pesticides through the mother’s diet, at a time in their development equivalent to a human baby’s second trimester in the womb, their metabolism changes in two ways: their cholesterol and triglycerides rise.  These abnormal and lasting changes resemble the major factors that predict and lead, later in life, to obesity, diabetes and cardiovascular heart disease (specifically, atherosclerosis, a condition in which fatty material collects along the arteries and hardens artery walls).

These changes in metabolism happen at low levels, within the levels we are uniformly exposed to, which the Environmental Protection Agency declares as “safe” but are evidently not.  The changes are the strongest when the mother rats are fed a high-fat diet.  Human babies may even be underweight at birth (and there’s an epidemic of underweight babies in the U.S.), but quickly become overweight

Humans run into these pesticides in our food and water.  Of course, children continue to be exposed once they are born and are in fact exposed more than adults because they eat and drink more in relation to their body weight and have a higher ratio of skin.

The other groups of people exposed most to organophosphates and other pesticides are the same groups with the highest rates of obesity – people who live in run-down inner-city neighborhoods, the poor, and farmworkers.  Again, not a coincidence but a connection, a trigger.

Dr. Ted Slotkin of Duke University, the researcher responsible for these discoveries, found another compelling clue: exposure caused harm to the rodent’s brain, as well as its metabolism.  Once the exposed lab animal was born and started to eat at will, its consumption of a high-fat diet reduced the adverse symptoms in its brain functioning.  As Dr. Slotkin muses, “If you’ve got neurofunctional deficits, and they can be offset by continually eating Big Macs, then you will naturally (but unconsciously) select that kind of food because it will make you feel better.”  Unfortunately, increased fat will further harm the animal’s, or human’s, metabolism.

What this means for you:

Particularly while trying to conceive, during pregnancy, while nursing, and for your children, avoid pesticides; eat organic foods.

For information about endocrine disruptors, read the new booklet published by the nonprofit Learning and Developmental Disabilities Initiative.

Author: Alice Shabecoff for CSN – Chemical Sensitivity Network, November 5, 2009

Alice Shabecoff is the co-author with her husband Philip of Poisoned Profits: The Toxic Assault on our Children, published by Random House last year.  See their website, www.poisonedprofits.com

Related article from Alice Shabecoff:

• Our planet, our children – How are your children doing?

Exposure during pregnancy to the chemical bisphenol A, or BPA, found in many common plastic household items, is known to cause a fertility defect in the mother’s offspring in animal studies, and now researchers have found how the defect occurs. The results of the new study will be presented Saturday at The Endocrine Society’s 91st Annual Meeting in Washington, D.C.

The study, funded partly by the National Institutes of Health, joins a growing body of animal research showing the toxic health effects of BPA, including reproductive and developmental problems. Last August the U.S. Food and Drug Administration found BPA to be safe as currently used but later said more research on its safety is needed. BPA is used to make hard polycarbonate plastic, such as for baby bottles, refillable water bottles and food containers, as well as to make the linings of metal food cans.

BPA has estrogen-like properties and in pregnant animals has been linked to female infertility.

“The big mystery is how does exposure to this estrogen-like substance during a brief period in pregnancy lead to a change in uterine function,” said study co-author Hugh Taylor, MD, professor and chief of the reproductive endocrinology section at Yale University School of Medicine.

To find the answer to that question, Taylor and his co-workers at Yale injected pregnant mice with a low dose of BPA on pregnancy days 9 to 16. After the mice gave birth, the scientists analyzed the uterus of female offspring and extracted DNA.

They found that BPA exposure during pregnancy had a lasting effect on one of the genes that is responsible for uterine development and subsequent fertility in both mice and humans (HOXA10). Furthermore, these changes in the offspring’s uterine DNA resulted in a permanent increase in estrogen sensitivity. The authors believe that this process causes the overexpression of the HOXA10 gene in adult mice that they found in previous studies.

The permanent DNA changes in the BPA-exposed offspring were not apparent in the offspring of mice that did not receive BPA injection (the controls). This finding demonstrates that the fetus is sensitive to BPA in mice and likely also in humans, Taylor said.

“We don’t know what a safe level of BPA is, so pregnant women should avoid BPA exposure,” Taylor said. “There is nothing to lose by avoiding items made with BPA—and maybe a lot to gain.”

Reference: The Endocrine Society, Bisphenol A exposure in pregnant mice permanently changes DNA of offspring, 10-Jun-2009

Past animal studies show that bisphenol A, or BPA, can have harmful effects on the reproductive, nervous and immune systems. Also, a study in humans reported last year found an increased prevalence of cardiovascular disease in people with high levels of BPA in the urine.

However, the effects of BPA on the heart are unknown, said study co-author Scott Belcher, PhD, associate professor in the University of Cincinnati’s Department of Pharmacology and Cell Biophysics.

In the new study, funded by the National Institutes of Health, the University of Cincinnati researchers found that low-dose BPA and estrogen can act alone or in combination to increase harmful arrhythmias in female rats and mice. Because BPA has properties similar to the main female hormone estrogen, it is considered an “environmental estrogen.”

Mice and rats in the study had normal heart rhythms at baseline, before administration of BPA or estrogen (estradiol), Belcher said. The investigators studied heart rhythms in both the working heart and in cultured heart muscle cells. In both models, exposure to BPA increased the frequency of arrhythmias, compared to baseline, in females but not in male animals, the authors found. Administration of estrogen alone also increased the frequency of arrhythmias in females.

Arrhythmias were most frequent in the female rats and mice when they received both BPA and estrogen, at levels normally found in female humans.

“We have identified a new possible risk for female heart health, caused by increased levels of estrogens in the body and exposure to the environmental estrogen BPA,” Belcher said.

BPA is found in polycarbonate-plastic baby bottles, refillable water bottles and food containers as well as the linings of metal food cans. Last year the U.S. Food and Drug Administration said more research on the safety of BPA is needed.

Arrhythmias occur when the heart beats too slowly or too fast or when it skips heartbeats. These heart rhythm irregularities can cause fatigue, lightheadedness, fainting or sudden cardiac death. If a fast heart rate affects the heart’s ability to pump, it can cause a heart attack.

The study’s lead author, Hong-Sheng Wang, PhD, assistant professor at the University of Cincinnati, will present the results.

Reference: The Endocrine Society, Bisphenol A exposure increases risk of abnormal heart rhythms in female rodents, 10-Jun-2009

People are likely being exposed to the commonly used chemical bisphenol A (BPA) at levels much higher than the recommended safe daily dose, according to a new study in monkeys. The results will be presented Thursday at The Endocrine Society’s 91st Annual Meeting in Washington, D.C.

“BPA is now known to be a potent estrogen,” said Frederick vom Saal, PhD, a co-author of the new study and a professor of biological sciences at the University of Missouri-Columbia. “Human and animal studies indicate it could be related to diabetes, heart disease, liver abnormalities, miscarriage and other reproductive abnormalities, as well as prostate and breast cancer.”

The U.S. Food and Drug Administration (FDA) declared BPA is safe based on estimates that people consume only small amounts each day from food. However, recent research indicated that U.S. adults are exposed to more BPA from multiple sources than previously thought, vom Saal said.

BPA is found in polycarbonate plastic food and beverage containers, such as water and infant bottles, as well as in the epoxy resin lining of cans and other sources. The chemical can leach into food and beverages, according to the National Institutes of Health, which funded the study by vom Saal and colleagues.

“Between 8 and 9 billion pounds of BPA are used in products every year,” vom Saal said.

In their study, he and his colleagues fed five female adult monkeys an oral dose of BPA (400 micrograms per kilogram of body weight). This amount is more than 400 times higher than the amount that the U.S. Food and Drug Administration (FDA) estimates that human adults are exposed to and 8 times higher than the estimated safe daily amount to consume, according to vom Saal.

Yet the blood levels of biologically active BPA over the next 24 hours were lower in the monkeys than the average levels found in people in the United States and other developed countries, vom Saal said. For levels to be higher in people when measured, their exposure dose must be greater than that given to the monkeys, he explained.

“These results suggest that the average person is likely exposed to a daily dose of BPA that far exceeds the current estimated safe daily intake dose,” vom Saal said.

He said that BPA exposure must come from many unknown sources, in addition to food and beverage containers. Like drugs, BPA acts in pulses, with each exposure creating a high-level pulse before it is cleared in the urine, according to vom Saal.

The researchers are continuing the study in more monkeys, but vom Saal said they do not expect to get different findings because the data in the first five animals were “very consistent.” The species of monkey that they used (rhesus) metabolizes BPA similar to humans, he added.

Reference: The Endocrine Society, Our exposure to controversial chemical may be greater than dose considered safe, 10-Jun-2009