Presence and formation of cobalamin analogues in multivitamin-mineral pills

Abstract

Because the origin of cobalamin (vitamin B12) analogues in animal chows and animal and human blood and tissues is unknown, the authors investigated the possibility that multivitamin interactions might convert cobalamin to cobalamin analogues. They homogenized three popular multivitamin-mineral pills in water, incubated them at 37°C for 2 hr, and isolated the cobalamin. Using paper chromatography the authors observed that 20-90% of the cobalamin was present as cobalamin analogues. Studies using CN-[57Co]cobalamin showed that these analogues were formed due to the concerted action of vitamin C, thiamine, and copper on CN-cobalamin. These cobalamin analogues are absorbed from the gastrointestinal tract of mice and either fail to stimulate or actually inhibit cobalamin-dependent enzymes when injected parenterally. It is concluded that CN-cobalamin can be converted to potentially harmful cobalamin analogues by multivitamin-mineral interactions and that these interactions may be responsible for the presence of cobalamin analogues in animal chows and animal and human blood and tissues.