Summary

It may be time for action on bisphenol A, the basis of a chemical used in many everyday products. A new study shows it is linked with metabolic abnormalities that could set the scene for diabetes. This adds to previous evidence that suggests bisphenol A acts like an environmental hormone and exposure may store up health problems for the future.

Introduction

Bisphenol A (BPA) is the basis of polymers found in many everyday products, such as polycarbonate plastic food and drink containers. It is already known to have estrogen-like effects, from animal and lab experiments. A population survey now suggests that bisphenol A may be linked to diabetes and heart disease. Therefore, experts at the University of Missouri are calling for the regulatory authorities to take a tougher stand on exposure.

The evidence so far

Frederick vom Saal and John Peterson Myers of the University of Missouri, in their editorial, say that we have known for more than ten years that exposure to BPA at exposures far below that currently set by the United States Food and Drug Administration have adverse effects on the brain, reproductive system and metabolic processes in animals. Rats fed a dose 250 times less than the current limit for a month had decreased levels of antioxidants and increased lipid peroxidation - both of which could set the scene for heart disease. Mice given a dose five times below the limit developed insulin resistance.

What about humans?

A new study from analysis of data from the National Health and Nutrition Examination Survey 2003-2004 shows that there is a link between urine levels of BPA, cardiovascular disease, type 2 diabetes, and liver enzyme abnormalities. The University of Missouri experts also point out that the current 'epidemic' of obesity and diabetes coincides with a massive increase in use of and exposure to BPA - so maybe there is a link?

What should be done?

First, we need more research on human populations to tease out the true relationship between BPA exposure and human health problems. And the regulatory authorities need to take some action. In Canada, BPA has been classed as a toxic chemical and exposures are now strictly limited. US Federal legislation recently limited human exposures to a similar group of environmental chemicals, the phthalates, which have similar effects. The food and chemicals industry, for their part, ought to be looking for 'greener' and safer alternatives to BPA to use in packaging and other applications.