1. Northern Ireland Centre for Diet and Health, University of Ulster, Coleraine BT52 1SA, Northern Ireland, U.K.
2. Department of Nutrition and Dietetics, Nutrition Food and Health Research Centre, King's College London, Campden Hill Road, London W8 7AH, U.K.
3. Folkhälsan Research Center, Department of Clinical Chemistry, P.O. Box 60, FIN-00014 Helsinki, Finland
4. BIBRA International, Woodmansterne Road, Carshalton, Surrey SM5 4DS, U.K.