By David Derbyshire
Gender-bending chemicals in food packaging, drink cans and baby bottles may double the risk of heart disease, a new study has found.
Researchers have shown that people with higher-than-normal levels of bisphenol A in their blood are more likely to suffer from potentially dangerous heart problems.
The chemical – which mimics the female sex hormone oestrogen – also appears to raise the risk of diabetes, even though the amount found in tests on nearly 1,500 people fell far short of official safety limits.
It is the first time that bisphenol A – BPA for short – has been linked to health problems in people and raises disturbing questions about one of the most common chemicals in everyday use.
It is used to make linings of food and drink cans and is also found in plastic bottles, CD cases, plastic knives and forks and dental sealants.
Although some animal studies have shown it is safe, others have raised serious concerns.
BPA has been linked to breast cancer, liver damage, obesity, diabetes, fertility problems in men and developmental disorders in babies.
Prof David Melzer, at the Peninsula Medical School, Exeter, who led the research, said: ‘Our study has revealed for the first time an association between raised BPA loads and two common diseases in adults.
‘At the moment, we can’t be absolutely sure that BPA is the direct cause of the extra cases of heart disease and diabetes – if it is, some causes of these serious conditions could be prevented by reducing BPA exposure.’
The study, published today in the Journal of the American Medical Association, looked at blood and urine samples of 1,455 adults aged between 18 and 74 years collected by the American Government’s National Health and Nutrition Examination Survey in 2003 and 2004.
The 25 per cent of people with the highest levels of BPA were twice as likely to suffer heart disease or diabetes than the bottom 25 per cent, even when other factors such as weight, diet, income and age were taken into account.
Higher levels were also linked to abnormal concentrations of liver enzymes – a possible sign of liver damage.
The links were strongest for young people.
The levels of BPA were relatively small – suggesting the people in the study were consuming around 20 micrograms of the chemical a day. The minimum safety level is around 3,000 micrograms a day.
Prof Tamara Galloway, a toxicologist at Exeter University and co-author of the study, said more research was needed to find out if low BPA exposure caused health problems – or whether people with heart disease and diabetes just happened to have higher exposure because of their lifestyle or diet.
‘Bisphenol A is one of the world’s most widely produced and used chemicals, and one of the problems until now is we don’t know what has been happening in the general population,’ she said.
The scientists don’t know how BPA could increase the risk of heart disease and diabetes. However, it could lead to more fat being laid down in the arteries and interfere with the way insulin is processed .
Prof David Coggon, who teaches occupational and environmental medicine at the University of Southampton, said: ‘There is now a need to establish whether the association of BPA with heart disease and diabetes can be independently replicated, and if so, whether BPA is a cause of the disorders or is linked to them in some other way.
‘If low-level BPA were confirmed to cause disease, there would be a need to review controls on sources of exposure to the chemical.’
Other researchers urged caution over the results.
Prof Richard Sharpe, Medical Research Council Human Reproductive Sciences Unit, University of Edinburgh, said: ‘There may be an altogether more common sense – although still scary – explanation for the observations in this study.
‘That is, that if you drink lots of high-sugar canned drinks you will over time increase your risk of cardiovascular diseases and diabetes – I think we already suspect this – and incidentally you will be exposed to more bisphenol A from the can lining.
‘The fact that the younger age groups in this study had the highest bisphenol A exposures would certainly fit with this.’
• Bisphenol A is used to make polycarbonate plastic – a clear shatter-resistant material found in baby bottles, CD cases, spectacle lenses, plastic forks and sports equipment.
• It is also used to make resins that line the inside of food and drink cans. BPA is used in dental fillings.
• People are exposed to BPA when it leaches out of plastic into liquid – particularly when hot.
• It may also escape from landfill sites into the water.
• The chemical is found in the bodies of more than 90 per cent of people.
• It mimics the sex hormone oestrogen – linked in laboratory studies to breast cancer, genital abnormalities in baby boys and liver problems.
• It is one of the most common artificial chemicals, with factories producing more than 2.2 million tonnes a year.