Dr. Ron’s Research Review – November 12, 2014

© 2014

This week’s research review focuses on Vitamin B12 forms.

There are two active co-enzyme forms of vitamin B12 (adenosyl and methyl cobalamin) along with two precursors (cyano and hydroxyo).
Adenosylcobalamin is the cofactor of Methylmalonyl Coenzyme A mutase (MUT). Adenosylcobalamin deficiency disturbs the carbohydrate, fat and amino-acid metabolism, and hence interferes with the formation of myelin.
Methylcobalamin is the cofactor of enzyme Methionine synthase, which is responsible for conversion of homocysteine to methionine and of 5-methyltetrahydrofolate to tetrahydrofolate. Methylcobalamin is primarily involved along with folate in hematopiesis and development of the brain during childhood.
Cyanocobalamin is the most common form of B12 in the US, and is converted into hydroxocobalamin by removing the cyanide moiety and replacing it with a hydroxyl group. Cyanocobalamin does not occur in nature, but is produced from bacterial hydroxocobalamin
Hydroxocobalamin is preferred in many countries is due to its long retention in the body and the need for less-frequent IM injections in restoring vitamin B12 (cobalamin) serum levels. It is converted to either methylcobalamin or 5-deoxyadenosyl cobalamin.

Combination Treatment

Thereby, it is important to treat vitamin B12 deficiency with a combination of methylcobalamin and adenosylcobalamin or hydroxocobalamin or cyancobalamin. (Thakkar and Billa, 2014)

Dr. Ron


Articles

 

Treatment of vitamin B12 deficiency-Methylcobalamine? Cyancobalamine? Hydroxocobalamin?-clearing the confusion.
            (Thakkar and Billa, 2014) Download
Vitamin B12 (cyancobalamin, Cbl) has two active co-enzyme forms, methylcobalamin (MeCbl) and adenosylcobalamin (AdCbl). There has been a paradigm shift in the treatment of vitamin B12 deficiency such that MeCbl is being extensively used and promoted. This is despite the fact that both MeCbl and AdCbl are essential and have distinct metabolic fates and functions. MeCbl is primarily involved along with folate in hematopiesis and development of the brain during childhood. Whereas deficiency of AdCbl disturbs the carbohydrate, fat and amino-acid metabolism, and hence interferes with the formation of myelin. Thereby, it is important to treat vitamin B12 deficiency with a combination of MeCbl and AdCbl or hydroxocobalamin or Cbl. Regarding the route, it has been proved that the oral route is comparable to the intramuscular route for rectifying vitamin B12 deficiency.European Journal of Clinical Nutrition advance online publication, 13 August 2014; doi:10.1038/ejcn.2014.165.

 

References

Thakkar, K and G Billa (2014), ‘Treatment of vitamin B12 deficiency-Methylcobalamine? Cyancobalamine? Hydroxocobalamin?-clearing the confusion.’, Eur J Clin Nutr, PubMedID: 25117994