Vitamin B12-Causes and its 6 most important Deficiency manifestations

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Causes of Deficiency of Vitamin B12

The causes of Vitamin B12 are:

Nutritional
Decreased Absorption
Addisonian Pernicious Anemia
Gastric Atrophy
Pregnancy
Fish Tapeworm

1. Nutritional

Nutritional Vitamin B₁₂ deficiency is very common in underdeveloped countries, especially among vegetarians of low socioeconomic group.
The only source for B₁₂ in vegetarian diet is curd/milk, and lower income group may not be able to afford it.

2. Decreased Absorption

Absorptive surface is reduced by gastrectomy, resection of ileum and malabsorption syndromes.
So there may be deficiency of Vitamin in these cases.

3. Addisonian Pernicious Anemia

It is common in European countries. When it was described in 1849 by Thomas Addison, it was pernicious (fatal), without any known remedy.
It is manifested usually in persons over 40 years.
It is an autoimmune disease with a strong familial background.
Antibodies are generated against IF (Intrinsic Factor).
So, IF becomes deficient, leading to defective absorption of B12.

4. Gastric Atrophy

Although true Addisonian pernicious anemia is rare, similar atrophy of gastric epithelium leading to deficiency of IF and decreased B12 absorption is common.
In chronic iron deficiency anemia, there is generalized mucosal atrophy.
In about 40% cases of iron deficiency anemia, superadded gastric atrophy is seen.

5. Pregnancy

Increased requirement of vitamin in pregnancy is another common cause for Vitamin B₁₂ deficiency.

6. Fish Tapeworm

The fish tapeworm, diphillobothrium latum infection is common in Scandinavian countries where eating live fish is a delicacy.
This tapeworm has a special affinity to B₁₂ causing reduction in available vitamin.

Deficiency Manifestations of Vitamin B12

1. Folate Trap

Vitamin B₁₂ deficiency causes…

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