Professor Murray Mitchell - Walking the Talk 

When a researcher walks the talk - for example, refuses to use plastic baby bottles for his children - you know that concern about exposure to toxins - in this case endocrine disrupting chemicals (EDCs) in our environment - is no longer just theoretical. In fact, it is what leading international researchers, such as Professor Murray Mitchell, do in their everyday lives that make people sit up and take notice.

Prof Mitchell has all the necessary bona fides to be one of the four speakers at BCN's Breast Cancer and Environmental Risk seminar and expert panel in July.

Formerly the Deputy Director of the Liggins Institute in Auckland, the Professor of Pharmacology and Obstetrics and Gynaecology took up the position of Director of the University of Queensland's Centre for Clinical Research in February 2010. 

Prof Mitchell has received worldwide recognition for his research on the causes and consequences of pre-term birth and the long-term health effects of developmental exposure to environmental chemicals, and he has published over 400 peer-reviewed papers in wide range of prestigious medical and scientific journals.

His current work focuses on how environmental factors can modify the actions of key genes in the foetus and placenta to influence, not only the course of a pregnancy, but the baby's health as an adult.

I ask Prof Mitchell how he went from research into the causes and impacts of pre-term birth - for which he is probably best known - to endocrine disrupting chemicals and breast cancer, which is one of the main areas of interest at our seminar in July. It strikes me that there is not an entirely linear connection. 

"It was a coming together of some background research," he says. 

"My original degree was in chemistry, and I was head of Pharmacology at Auckland University. At the time there was lots of talk about bisphenol A, and "fighting" about it within the US FDA." Together with some intermittent work of his own on breast cancer, the connection between breast cancer and BPA piqued his interest. 

Most research on exposure to BPA and other EDCs in utero has been in animal models. If readers go back to Upfront U Kaiora interviews with Dr Maricel Maffini in 2007-2008, they will recall her work with pregnant rats and BPA. However, Prof Mitchell says that the human placenta differs markedly from other mammalian animals although it is not known why. 

The placenta is very good at metabolising some toxic compounds in order to protect the developing baby. And even the oestrogens that women produce at extraordinary levels in order to sustain a pregnancy, are prevented from crossing the placenta to harm the baby. The problem is that the placenta does not recognise modern compounds. For example, natural oestrogens are conjugated or broken down by placental enzymes and don't get through. Although BPA acts like oestrogen it doesn't "look" like oestrogen and it passes straight through.

"It is not just BPA," says Prof Mitchell. "Other compounds such as phthalates and genistein [a soy isoflavone] also get through."

"Genistein is a frighteningly active compound," he says.

It is also not just a problem for girls, but for boys as well, as these toxins affect androgens (male hormones which stimulate or control the development and maintenance of male characteristics) as well as oestrogen. In addition, studies on BPA have shown it to be active in the brain and exposure is associated with more gender neutral play in young boys.

We shift focus from in utero exposures to baby bottles and other plastic items. "BPA exposure is a significant problem," he goes on, "but mercifully, almost all baby bottles are now BPA free."

Which brings us around to "walking the talk". When Prof Mitchel and Prof Peter Lobie gave evidence on behalf of BCN to the Health Select Committee, in support of the 2006 petition to Parliament, the committee sat up and listened when the two researchers talked of what they did in their own lives, of decisions not to use plastic baby bottles and so on.

It seems pretty obvious to me from the research I've read, that in utero exposures to toxins - in fact, much of what goes on in a mother's life during pregnancy - has a huge impact on the subsequent health of her child. So why is it that, in general, the public don't understand how important this is?

Prof. Mitchell responds with a multi-faceted answer: fighting in the FDA (an organisation from which many countries, including New Zealand, take their lead), political correctness gone mad, big business and highly financed lobbying. For example, in a US congressional investigation into the issue of EDCs, researchers and people who had the knowledge about EDCs were not allowed to present to the hearing because they were regarded as 'biased'.

And why does this situation continue?

Because big business has huge resources to lobby governments and it is hard to prioritise the research dollar. We are creating chemical compounds faster that we can research them and assess their safety. Prof Mitchell says the rate at which we generate new compounds is frightening - plastics, chemicals for keeping our food edible longer - it is all happening faster than we can regulate.

After a discussion on BPA in our water supply - did you know that it is very hard to remove BPA from water and it is almost impossible to get pure, BPA free water, for research purposes - I ask Prof Mitchell what needs to be done.

"Researchers need to get the current knowledge out to the public. While governments need categorical results before they take action, researchers need to get the messages out. Science needs to go to the community and work with local groups. We need to tell people what they can do as individuals."

"Events such as BCNs seminar are vital for getting the message out."

And his final message to people? When it comes to the precautionary principle, there are no negatives for individuals making changes in their lives. There are no risks, only benefits.

Copyright © 2012 Sue Claridge

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