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
Digestive biscuit in some varieties. A digestive biscuit averages around 70 calories, although this sometimes varies according to the factors involved in its production. Digestive biscuits are frequently eaten with tea or coffee. Sometimes, the biscuit is dunked into the tea and eaten quickly due to the biscuit's tendency to disintegrate when wet. Digestive biscuits are one of the top 10 biscuits in the United Kingdom for dunking in tea. The digestive biscuit is also used as a cracker with cheeses, and is often included in "cracker selection" packets. In the UK, McVitie's digestive is the best selling biscuit, with 80 million