C I Vardavas1, A G Kafatos2. 1. Preventive Medicine and Nutrition Unit, Faculty of Medicine, University of Crete, PO Box 2208, 71003, Crete, Greece. 2. Preventive Medicine and Nutrition Unit, Faculty of Medicine, University of Crete, PO Box 2208, 71003, Crete, Greece. Electronic address: kafatos@med.uoc.gr.