Thursday April 1 2010
Bisphenol A is a chemical used in plastics
The Independent has published a series of reports into bisphenol A (BPA), a “controversial chemical” that, it says, is present in some of the best-known foods and leading-brand baby bottles. The newspaper quotes experts in occupational health, who have said that the continued use of BPA in the UK raises important questions about how we safeguard public health from chemicals. They call for action by the government, but say that retailers could make efforts to reduce our exposure to this chemical.
It is appropriate to be cautious about the use of chemicals that have the potential to be toxic. A lower level of evidence, for example from animal studies or human research in small numbers of people, is often enough to support restrictions in their use. The analysis of toxicology data from multiple data sources can be complex and at times conflicting. All the available evidence will need to be considered by a properly constituted group of experts for this issue to be resolved.
BPA is found in many household items, and it may be hard to completely avoid exposure in daily life. The US Department of Health and Human Services has published BPA information for parents to help reduce their child’s exposure.
The European Food Safety Authority (EFSA) is currently reviewing BPA to ensure that its policy is based on the most up-to-date information possible. The opinion is likely to be adopted by the organisation in May this year. Some countries have taken precautions, including Canada, which has introduced legislation to ban the use of the chemical in baby feeding bottles. The EFSA will review the relevance of the new study that led to the ban in Canada. The results of this evaluation are due in May 2010, at which point further advice should be available.
What is BPA?
BPA is a common chemical, also known as 4,4’-dihydroxy-2,2-diphenylpropane. It is mainly used in combination with other chemicals in the manufacture of plastics and resins.
BPA is used in the production of polycarbonate, a high-performance transparent, rigid plastic. Polycarbonate is used to make food containers, such as some beverage bottles, infant feeding (baby) bottles, tableware (plates and mugs) and storage containers.
Residues of BPA are also present in epoxy resins, used to make protective coatings and linings for food and beverage cans and vats.
BPA can migrate in small amounts into food and beverages stored in materials containing the substance. As it is such a common chemical that has been in use for several decades, it can be found in small quantities in the urine of most adults.
How may BPA affect you?
The science is not yet completely clear on how BPA may affect humans. BPA may mimic hormones and interfere with the endocrine system of glands, which release hormones around the body. Some scientists think that if it interferes with sex hormones, this could affect puberty or the menopause or cause cancers that are related to hormones. Those calling for a ban suggest that it may be a factor in a rising numbers of human illnesses, such as breast cancer, heart disease and genital birth defects.
There is a growing call to stop manufacturing plastics with BPA and using BPA in food containers as there are less hazardous alternatives.
What does the science say about BPA?
There is a growing body of research into the safety of BPA, but no single study conclusively proves that BPA is harmful to humans.
There is a lack of human data in this area, which is a problem. This is mainly due to the difficulty in finding people who have not been exposed to BPA. There are also ethical constraints. For example, it is not possible to test potentially harmful chemicals on pregnant women to see the effects on their children. This means that researchers depend on animal studies, which have only limited application to humans. Animal research has connected BPA exposure to a range of health problems in mice or rats, including metabolic disorders and obesity, male fertility problems, asthma and intestinal inflammation.
A study in 2010 conducted by researchers in the US retrospectively assessed the association between urinary levels of BPA in 2,948 adults and their cardiovascular outcomes. It concluded that BPA exposure is “consistently associated with reported heart disease in the general adult population of the USA”. The researchers say that further studies are needed to clarify the mechanisms behind these associations. The relevance of this study is being reviewed as part of EFSA’s assessment of the European policy on BPA.
What are other countries doing?
Most countries have not listed the chemical as a health hazard.
In January 2010, the US Food and Drug Administration, which is responsible for protecting and promoting Americans' health through regulation and supervision of food safety, expressed concern over the impact of BPA on the brains and development of young children. It said it was "taking reasonable steps to reduce human exposure" to BPA in the food supply. Canada and some American states have banned the use of BPA in baby feeding bottles.
The EFSA is currently carrying out a review of BPA. In October 2009, the European Commission asked the EFSA to assess the relevance of a new study on possible neurodevelopmental effects of BPA. The study in question was commissioned by the American Chemistry Council to address safety concerns raised by the Canadian government. The EFSA aims to complete its evaluation by May 2010, in line with the deadline set by the Commission.
If I wanted to, how do I avoid BPA?
Individuals may find it hard to avoid BPA completely. They can choose products that do not have BPA in them. The US Department of Health and Human Services has published BPA information for parents on reducing their child’s exposure.
People can also ask manufacturers to label their products if they contain BPA. Regulators are currently considering this issue. By May 2010, the EFSA will have published its report into BPA, and there will be greater certainty as to what the safe or unsafe levels of this chemical are.