Human digestive system in the small intestine. Water and minerals are reabsorbed back into the blood in the colon of the large intestine, where the environment is slightly acidic. Some vitamins, such as biotin and vitamin K produced by bacteria in the gut flora of the colon are also absorbed. The parietal cells in the fundus of the stomach, produce a glycoprotein called intrinsic factor which is essential for the absorption of vitamin B12. Vitamin B12 (cobalamin), is carried to, and through the stomach, bound to a glycoprotein secreted by the salivary glands - transcobalamin I also called haptocorrin, which protects the acid-sensitive
National Institute of Diabetes and Digestive and Kidney Diseases National Institute of Diabetes and Digestive and Kidney Diseases The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is part of the United States National Institutes of Health, which in turn is part of the Department of Health and Human Services. NIDDK is approximately the fifth-largest of the 27 NIH institutes. The institute's mission is to support research, training, and communication with the public in the topic areas of "diabetes and other endocrine and metabolic diseases; digestive diseases, nutritional disorders, and obesity; and kidney, urologic, and hematologic diseases". As of 2015, the Director of the institute is Dr.