Manuela M Bergmann1, Vicent Hernandez2, Andrew Hart3,4. 1. Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbrücke, Potsdam, Germany. bergmann@dife.de. 2. Department of Gastroenterology Instituto de Investigación Biomédica, Estrutura Organizativa de Xestión Integrada de Vigo, Vigo, Spain. 3. Norwich Medical School, Department of Medicine, University of East Anglia, Norwich, UK. 4. Norfolk and Norwich University Hospital NHS Trust, Norwich, UK.