BPA Dangers and Heart Disease

by Leigh on March 1, 2012

what is bpa free - heart disease

Go BPA free to lower risk factors for heart disease

The Naturally Healthy Heart blog aims to keep you abreast of recent developments in cardiovascular health such as the news that yet more research has found a link between BPA and heart disease. Bisphenol A (BPA) is a fairly ubiquitous chemical found in the linings of many types of food packaging, hardened plastic bottles (including many sports drink bottles), and also in dental sealants. Previous research has also linked the chemical to heart disease and yet little has been done to regulate our exposure to what appears to be quite a significant danger to our health.

BPA-Free and Heart Disease

The latest research comes courtesy of scientists in Exeter, UK, who published a paper in the journal Circulation last month noting a statistically significant association between apparent BPA exposure and coronary heart disease. Dr David Melzer, the lead researcher at the Peninsula College of Medicine and Dentistry admits to being stunned as to the association and the fact that billions of people around the world are exposed to BPA daily without any human safety studies carried out. The most sensible course of action appears to be going BPA free unless safety studies can prove the chemical safe – check your water bottle before you head off for your heart-healthy fitness workout today or you might be undoing some of your good work before you’ve even started.

BPA Safety Research

Animal studies into the effects of BPA have been conducted but they used mice and rats and so are almost completely redundant when considering the chemical’s effects on humans. These animals excrete BPA through the bile whereas humans excrete BPA through the kidneys, making the rate of elimination and the possible damaging effects on the body very different. Whether this has simply been an oversight or a deliberately misleading tactic is unknown but many scientists concerned about the effects of BPA have called for proper human safety trials to be carried out as soon as possible.

What is BPA?

BPA has one of the highest production volumes of any chemical in the world and we are exposed to it daily through food and drink packaging. The polycarbonate linings of tins are often based on BPA and plastics designed to be more resilient, such as reusable drinks bottles or plastic food containers often use BPA. Heat leeches more of the chemical into the food or drink and so it is inadvisable to warm food up in these hard plastic containers that might contain polycarbonate. Other sources of BPA include dental sealants and drinking water as well as skin exposure and possible inhalation through household dust.

BPA Studies

The EPIC-Norfolk cohort study carried out in the UK is the basis of the latest research into the effects of BPA. Using data taken from the 10-yr follow-up of the study, the scientists in Exeter noted that the more BPA-metabolites in the urine the more likely the study’s participants were to develop coronary artery disease. A previous study in the US, the NHANES study, also found a similar association but had the drawback of being just a one-off measurement that was at risk of being confounded by other variables such as dietary change in patients diagnosed with heart disease. Such changes in nutrition could, theoretically, alter the intake of BPA. In the recent study however, both baseline concentrations of BPA at the start of the study and more recent BPA urinary excretion concentrations were measured, thereby providing a comparison that could rule out reverse causation.

what is bpa

Food packaging is not the only way we're exposed to BPA.

The UK EPIC-Norfolk Study and BPA Dangers

The scientists looked at around 750 participants in the study who went on to develop cardiovascular disease and around 850 others who did not develop CVD and compared their baseline BPA levels. There was an 11% increase in risk of CHD with every standard-deviation increase in BPA concentration, even when controlling for other factors known to contribute to heart disease, such as smoking. The US NHANES study had a much higher risk increase of 30-40% for those with higher BPA concentrations but the UK study participants’ levels of the chemical were much lower (about half) of those in the US patients. The two studies do support each other but neither account for the mechanism behind the apparent risk.

Why BPA is a Risk Factor for Heart Disease

Bisphenol A (BPA) is known to bind to oestrogen receptors as well as inducing liver damage and cellular damage through oxidation. Pancreatic cell function is also impaired by BPA and the chemical is thought to promote obesity as well. Connections between a drop in oestrogen in menopausal women and an increase in heart disease risk is well documented, as is the link between diabetes and cardiovascular dysfunction. It also makes sense that a compromised liver and increase in toxicity from oxidative cellular damage would further contribute to heart disease and circulatory dysfunction. Given the increasing amount of evidence linking heart disease and BPA, surely it is time for a more prudent approach. Removing BPA from food packaging would be a start and, perhaps, in the future the chemical can provide a cautionary tale for those wanting to assume a chemical is safe until proven otherwise rather than keeping it out of circulation until proven safe.

References

Melzer, D., Osborne, N.J., Henley, W.E., et al. Urinary bisphenol: A concentration and risk of future coronary artery disease in apparently healthy men and women. Circulation 2012; DOI: 10.1161/?CIRCULATIONAHA.111.069153.

Melzer, D., Rice, N.E., Lewis, C., Henley, W.E., Galloway, T.S., 2010 Association of Urinary Bisphenol A Concentration with Heart Disease: Evidence from NHANES 2003/06. PLoS ONE 5(1): e8673. doi:10.1371/journal.pone.0008673

Carwile, J.L., Michels, K.B., Urinary bisphenol A and obesity: NHANES 2003-2006, Environ Res. 2011 Aug;111(6):825-30. Epub 2011 Jun 14.

Melzer D, Harries L, Cipelli R, et al, Bisphenol A exposure is associated with in vivo estrogenic gene expression in adults. Environ Health Perspect. 2011 Dec;119(12):1788-93. Epub 2011 Aug 10.

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