aLMU University of Munich, Department of Paediatrics, Dr von Hauner Children's Hospital, LMU Medicine, Munich, Germany

bInstitute of Gastroenterology, Nutrition and Liver Diseases, Schneider Children's Medical Center, Eduarda and Dr Moshe Ishay Institute for the Study of the Effects of Natural Food on Human Health, School of Medicine, Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel

Correspondence to Prof. Berthold Koletzko, Department of Paediatrics, Dr von Hauner Children's Hospital, LMU Medicine, Lindwurmstr. 4, 80337 Munich, Germany. E-mail: [email protected]