USES:Vitamin B12 is necessary for the metabolism of all foods and it plays an important role in the incorporation of folic acid into red blood cells, which carry oxygen around the body.
Good levels of vitamin B12 are also important to prevent nerve degeneration.
Stomach acid and the stomach enzyme pepsin liberate vitamin B12 from food and allow it to bind to carriers, including intrinsic factor, that transport B12 to the small intestine where it is absorbed.
Vitamin B12 deficiency may lead to low red blood cell production and a type of anaemia known as megaloblastic.
Low levels of vitamin B12 may be caused by intrinsic factor deficiency, leading to pernicious anaemia.
Note that the use of antacids (to reduce symptoms such as acid reflux) may reduce stomach acid which is needed to release B12 from food.
Alcohol abuse and smoking also reduce levels of vitamin B12.
Vitamin B12 is found almost exclusively in animal products, especially red meat, so vegetarians and especially vegans are at risk of low B12 levels.