1. From the Departments of Nutritional Sciences (AL, PBP, and DLO), Radiology (BC), and Paediatrics (PBP), University of Toronto, Toronto, Canada; The Research Institute, The Hospital for Sick Children, Toronto, Canada (AL, SA, BC, PBP, and DLO); CDC, Atlanta, GA (ZF and CMP); and the Food Science and Human Nutrition Department, University of Florida, Gainesville, FL (JFG).