BPA study causes controversy, as usual

Controversy still rages over BPA, bisphenol A.

Plastic packaging containing chemical BPA ‘harming brain and nerve cell growth in babies’.

Scientists have found that bisphenol A (BPA), which is used in a variety of consumer products ranging from fizzy-drink cans to food mixers, affects the function of a gene called Kcc2 which is involved in the growth of neurons, or nerve cells, in the brain and spinal cord.

The study, based on rats and human neurons grown in the laboratory, found female nerve cells more susceptible to BPA than male neurons. This might explain why certain neurodevelopmental disorders in humans are more common in females, such as Rett syndrome, a severe form of autism found only in girls, the scientists said.

“Our findings improve our understanding of how environmental exposure to BPA can affect the regulation of the Kcc2 gene. However, we expect future studies to focus on what targets aside from Kcc2 are affected by BPA,” said Professor Liedtke, who led the study published in the Proceedings of the National Academy of Sciences.

Other scientists have, however, criticised the study for exposing neurons to relatively high doses of BPA that would not normally be encountered by the human body. They believe that suggestions of a link between BPA and human disorders are not supported by the evidence when it comes to realistic exposure levels.

Professor Andrew Bartholomaeus of the University of Canberra in Australia, said that any BPA consumed in food or drink is completely metabolised before it enters the blood stream, which means that cells within the body are not exposed to “free” BPA.

Oh, this controversy has been around for while now. Haven’t heard of it? Well here you go, here it is in a concise complete read:

Science-Based Medicine » Bisphenol A in Plastics – Should We Worry?.

The concern is that BPA can leech from plastic containers into the food or liquid it contains, and when consumed can have negative health effects. The debate is over how to interpret existing evidence about BPA safety, which gives conflicting results. Essentially it is a debate about how to weight different kinds of evidence, and where safety thresholds should be.

What is the conclusion? That there is a small but possibly real effect here. Since toxicity is dependent on dose, we should limit our use of such plastics especially when they can leach out into our foods. Thus, BPA is banned in baby bottles and is being phased out in water bottles and food containers. However, what will replace BPA? Will that be safe? Or worse.

New science on BPA meets outdated analysis at FDA.

Learn how to cut your dietary bisphenol a exposure..

  5 comments for “BPA study causes controversy, as usual

  1. February 26, 2013 at 1:42 PM

    Nalgene has replaced their BPA based polycarbonate bottles with a copolyester called “Tritan.”

    • February 26, 2013 at 1:44 PM

      Matt: Does that have safety issues?

  2. Chris Howard
    February 26, 2013 at 1:43 PM

    I’ve heard that vegetable oil based plastics can be used instead of BPA, as a “safer” alternative.

    I’ve got a psychology/sociology background, so “soft-science” and definitely not trained in chemistry, or biology.

    Does anyone know if that is true?

  3. One Eyed Jack
    February 26, 2013 at 3:00 PM

    BPA is also a plasticizer. I’m not certain of the current practice, but BPA was commonly used to in automobile dashboards to give it a semi-soft consistency. As it evaporates over the years, dashboards became harder and less flexible.

    The main danger with BPA appears to be its ability to bind with estrogen related receptors in the body (hence the reason that it may affect women more than men).

    As with all chemicals, a high enough dose is almost always dangerous. The question is whether the exposure level in real life is anywhere near the levels in the study.

  4. Rand
    February 27, 2013 at 5:55 PM

    Well, I can see reason for using “super high doses” in the research. If its a 1/10000 chance that a molecule of BHA would combine with [whatever biological process happens], and normal dosages mean that it takes 15-20 years to accumulate enough damage to be noticeable, the scientist can’t run an experiment which runs that long… only practical way is to beef up the dosage and extrapolate how many years it would take of “normal” dosage to get the equivalent damage. Hard to calculate that sort of thing.

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