Vitamin B-12 in vegetarians

When you stop eating vitaminB-12 (cobalamins), you will passes through four stages of negative cobalamin balance:

• Stage I-Serum depletion (low vitamin B-12 on transcobalamin II)
• Stage II-Cell depletion (low red cell vitamin B-12 concentrations)
• Stage III-Biochemical deficiency (slowed DNA synthesis)
• Stage IV-Clinical deficiency (anemia)

There are six ways you can get vitamin B-12 deficiency:

-Three inadequacies

• inadequate ingestion
• inadequate absorption
• inadequate utilization (defect in enzymes or other protein)

-Three excesses

• increased requirement (pregnacy)
• increased excreased (alcoholism)
• increased destruction (very high doses of vitamin C)

Dietary deficiency of vitamin B-12 results from strict vegan (all plant food) diet because there is no vitamin B-12 synthesized by any plant. Vegetarins who are not vegans (lactoovovegetarians and lactovegetarians) ingest adequate amounts of vitamin B-12 in animal (egg,milk and other) products.

If daily vitamin B-12 absorption continues to be less than daily vitamin B-12 loss, negative balance will progress to stage II, depletion of stores. Eventually, however, continuing slight negative balance will deplete vitamin B-12 stores, after which stage III negative balance occurs (biochemical deficiency).

Active vitamin B-12 can be destroyed by very high doses of vitamin C. Vitamin C acts as an antioxidant primarily at physiologic doses. At pharmacologic doses, in the presence of iron, it is one of the most potent oxidants known and drives iron-catalyzed free radical generation which can damage vitamin B-12.

Negative vitamin B-12 balance also common in a large group of eldery people.