1. Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
2. Department of Preventive and Social Medicine, University of Otago, P.O. Box 913, Dunedin 9016, New Zealand
3. CSIRO Food and Nutritional Sciences, P.O. Box 52, North Ryde, NSW 1670, Australia