Monday, October 25, 2010

What do we know about BPA: Bisphenol A

THREE letters lie at the heart of our modern world: BPA. Short for bisphenol A, a synthetic oestrogen, a staggering 3 billion kilograms of the stuff is produced annually, with an estimated value of $500,000 per hour to the global economy.

BPA is used in the production of a hard and transparent form of polycarbonate plastic used to create food and drink containers and other consumer goods. It is also used in the epoxy resins that line metal food cans, and as an ingredient in dental sealants.

In fact, we are so consistently exposed to BPA that over 90 per cent of us excrete BPA metabolites in our urine at any given time.

How exactly BPA enters the human body is not yet clear, although eating food kept in BPA-containing packaging, breathing household dust and handling plastics that contain BPA may all contribute to our daily exposure.

Currently, BPA is not listed on food or drink labels so millions of people have no way of knowing their daily exposure.

BPA was first reported in the scientific literature in the 1930s as a synthetic oestrogen, and it is this property that has led to most of the subsequent controversy.

Laboratory studies show that, at the right dose, BPA can act as a hormone mimic, binding not only to oestrogen receptors but to other related receptors, too. However, this "active" dose has been furiously contested in what has become an intense scientific dispute.


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