Chemistry of ascorbic acid The main use of -ascorbic acid and its salts is as food additives, mostly to combat oxidation. It is approved for this purpose in the EU with E number E300, USA, Australia, and New Zealand) Another major use of -ascorbic acid is as dietary supplement. Natural biosynthesis of vitamin C occurs in many plants, and animals, by a variety of processes. Eighty percent of the world's supply of ascorbic acid is produced in China. Ascorbic acid is prepared in industry from glucose in a method based on the historical Reichstein process. In the first of a five-step process, glucose is
Vitamin B12 leading to vitamin B deficiency. Protein-bound vitamin B must be released from the proteins by the action of digestive proteases in both the stomach and small intestine. Gastric acid releases the vitamin from food particles; therefore antacid and acid-blocking medications (especially proton-pump inhibitors) may inhibit absorption of B. B taken in a low-solubility, non-chewable supplement pill form may bypass the mouth and stomach and not mix with gastric acids, but acids are not necessary for the absorption of free B not bound to protein; acid is necessary only to recover naturally-occurring vitamin B from foods. R-protein (also known as haptocorrin