1. From the Research and Development department, Fresenius Medical Care, Bad Homburg, Germany (PWC, PW, and UMM); the Institut für Humanernährung und Lebensmittelkunde, Christian Albrechts-Universität, Kiel, Germany (MJM, AB-W, and OK); and the MRC Childhood Nutrition Research Centre, Institute of Child Health, London, United Kingdom (NJF)