According to number of studies serum B12 level is not a sensitive indicator for B12 deficiency.(1)
In other words, your levels could be within the normal limit but you could still be deficient.
More sensitivemethod of screening for vitamin B12 deficiency is measurement of serum methylmalonic acid and homocysteine levels, which are increased early in vitamin B12 deficiency.
- Two important enzymatic reactions in human body dependent on vitamin B12
- The first one: the conversion of methylmalonic acid (MMA) to succinyl-CaA using B12 . MMA is elevated in the absence of B12
- The second one: the conversion of homocysteine to methionine using B12 and folic acid as cofactors. Deficiency of B12 and folate leads to elevated homocysteine levels. (high homocysteine levels is associated with cardiovascular disease).
Vitamin B12 deficiency is associated with hematologic, neurologic, psychiatric implications and possibly cardiac implications
Diagnosis of Vitamin B12 Deficiency.
- Physical or neurological symptoms of deficiency -> supplement with methylcobalamin
- Low folate -> supplement with folate
- Interpretation of vitamin B12 levels in the blood
- < 100 pg per ml (74 pmol per L) –> B12 Deficiency
- > 400 pg per ml –> No B12 Deficiency
- 100 – 400 pg per ml (74-295 pmol per L)
- Check MMA and homocysteine levels
- Either levels elevated -> B12 deficiency
- Both Normal -> No B12 deficiency