Source of Vitamin B12 Cyanocobalamin is a plant-based source of B12, which is added to soymilk, vegan vitamins and found naturally in spirulina. Cow Milk provides the B12 nutritional requirements of human body. Some bodies are better at retaining B12 than others. The individual body has varying ability to absorb Vitamin B 12. Absorption of vitamin B12 adversely affected by these conditions : Lack of intrinsic factor, a glycoprotein secreted by the stomach. This condition is present in pernicious anemia. Poorly functioning terminal ileum (this refers to receptors in the small intestine). Part of the stomach surgically removed. Inadequate digestive enzymes and gastric acid. Impaired liver and/or pancreatic function: Liver stores B12, and secretes it in bile. The pancreas is part of the end stage of absorption. Old Age : Absorption of Vitamin B12 tends to decrease as you age. B12 is a factor in conditions normally associated with aging, which respond to supplements. B-vitamin...