Answer to Question 1
It can result from inadequate intake or poor absorption. Primary B12 deficiency is sometimes seen in vegans or infants being fed by B12-deficient mothers. Secondary B12 deficiency occurs when gastric cells do not produce intrinsic factor or hydrochloric acid as a result of age, genetic defects, GI infections, surgeries, or medications.
Answer to Question 2
Folate and B12 are both required to produce methionine from homocysteine. A deficiency of either of these vitamins causes a build-up of homocysteine. High levels of homocysteine are associated with increased risk for heart disease. Folate deficiency can mask vitamin B12 deficiency. Megaloblastic, macrocytic anemia associated with primary and secondary vitamin B12 deficiency is caused by secondary folate (THF) deficiency. Folate gets trapped as inactive 5-methyl THF when vitamin B12 is not available. Severe neurological damage can occur and be fatal if B12 deficiency is misdiagnosed as a folate deficiency.
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