Dhaka the 17th Dec., 2013— Vitamin B12 (cobalamin [Cbl]) is essential for maintaining healthy bodily function but higher than normal levels (reference range 200-600 pmol/L) may indicate that a patient is at risk of developing certain cancers, according to a study published November 18 in the Journal of the National Cancer Institute. Previous studies had suggested an association between high Cbl levels and specific cancers. Many take vitamins in excess of the daily requirement.  Vitamin B12 (cobalamin [Cbl]) is one such vitamin. It is therefore very risky to take vitamins including vitamin  B12 without the advice of the qualified physician.