1. Department of Internal Medicine (A.G., R.W., R.B., S.B.P., A.M.B.), Dallas, Texas 75235
2. Center for Human Nutrition (A.G., S.B.P.), University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75235
3. Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases (E.A., S.I.T.), Bethesda, Maryland 20892
4. Department of Dermatology (Z.Z.), Zinnah Postgraduate Medical Center, Karachi, Pakistan
5. The Gastroenterology Unit, Department of Pediatrics (F.G., N.K.), Hacettepe University \E Faculty of Medicine, Ankara 06100, Turkey
6. Departments of Medicine and Clinical Biochemistry (S.O.), University of Cambridge, Cambridge CB2 2QR, United Kingdom