1 Calcium Research Unit, Division of Nutrition, Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, 00014 Helsinki, Finland. suvi.itkonen@helsinki.fi.
2 Calcium Research Unit, Division of Nutrition, Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, 00014 Helsinki, Finland. christel.lamberg-allardt@helsinki.fi.