17/06/2021
There are many different vitamin B12 supplements, and choosing one can be confusing. There are 5 decisions to be made. The first three are:
1. The physical form of the supplement:
Oral supplements can be tablets, lozenges or liquids (eg sprays) and all have found to be effective. Injections are generally unnecessary (1) and not recommended for prevention of deficiency.
2. The formulation:
Some other nutrients that can be present in multi-nutrient supplements (including vitamin C, thiamine and copper) can inactivate vitamin B12, rendering the supplement ineffective (2). Therefore we recommend taking a single-nutrient vitamin B12 supplement.
3. The form of vitamin B12:
Vitamin B12 exists in several chemical forms. The forms that are used in our bodies are adenosylcobalamin and methylcobalamin, but these may not be very stable in supplement form, which would decrease their effectiveness. The cyanocobalamin form of B12 is the most widely studied and has proven to be able to be converted to both methylcobalamin and adenosylcobalamin in the body, is stable in supplement form and can prevent and reverse deficiency (3). For this reason it is the form generally recommended by evidence-based health professionals and researchers.
(1) Kuzminski, A. M., Del Giacco, E. J., Allen, R. H., Stabler, S. P., & Lindenbaum, J. (1998). Effective treatment of cobalamin deficiency with oral cobalamin. Blood, 92(4), 1191-1198. Retrieved from http://www.bloodjournal.org/content/bloodjournal/92/4/1191.full.pdf
(2) Kondo, H., Binder, M. J., Kolhouse, J. F., Smythe, W. R., Podell, E. R., & Allen, R. H. (1982). Presence and formation of cobalamin analogues in multivitamin-mineral pills. Journal of Clinical Investigation, 70(4), 889-898.
(3) Thakkar, K., & Billa, G. (2015). Treatment of vitamin B12 deficiency-methylcobalamine? Cyancobalamine? Hydroxocobalamin?-clearing the confusion. Eur J Clin Nutr, 69(1), 1-2.
