The normal value of serum vitamin B12 ranges from about 200 to 900 picogram/ml with a mean value of around 450 pg/ml. Vitamin B12 is found in foods that come from animal source, including fish, meat, poultry, eggs, milk, and milk products. The normal dietary intake should be about 2 to 3 µg (micrograms) per day. People who are vegans (not taking any animal product including milk) are advised to eat foods fortified with B12 or take a daily or weekly B12 supplement as its deficiency can lead to severe and irreversible brain and nerve damage. Hiatus hernia can be associated with B12 deficiency and you should either increase your intake of B12-rich food or take supplements.