Dr Karin Michels, an associate professor in the Department of Epidemiology at Harvard University in Massachusetts, will not eat food wrapped or stored in plastic, nor will she use a plastic shower curtain. Dr Michels, who is visiting New Zealand as guest of the Breast Cancer Research Trust as part of her research into the causes of breast cancer in women, said she & her research colleagues were "really concerned" about plastics & plasticisers used in every day life in many countries. "The plastic bottles we drink from, especially these hard plastic bottles which are reusable, the Tupperware, the baby bottles where we heat up milk & shower curtains - all release substances that screw up our hormone system." She said heating lunch in a plastic container in a microwave released substances into the food which entered the body. Bisthenol A was the substance that most concerned the medical research industry.