1. Division of Human Nutrition (M.B.Z.), Wageningen University, 6700 Wageningen, The Netherlands
2. Committee for Fluoride-Iodine Fortification of Salt (M.B.Z., H.B.), Swiss Academy of Medical Science, CH-3007 Bern, Switzerland
3. Laboratory for Human Nutrition (M.B.Z., R.F.H.), Swiss Federal Institute of Technology (Eidgenössische Technische Hochschule), CH-8092 Zürich, Switzerland