Department of Medical OncologyUniversity Medical Center Groningen, University of Groningen, Groningen, The Netherlands. DieticiansDepartment of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Department of Laboratory MedicineUniversity Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Department of EpidemiologyUniversity Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Department of GastroenterologyUniversity Medical Center Groningen, University of Groningen, Groningen, The Netherlands. Department of Medical OncologyUniversity Medical Center Groningen, University of Groningen, Groningen, The Netherlands a.walenkamp@umcg.nl.