Faculty of Medicine, University of Southampton and NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK. Nutrition in Medicine Research Group, Department of Pathology and Biomedical Science, University of Otago, Christchurch 8140, New Zealand. Linus Pauling Institute, Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA. Department Internal Medicine, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands.