Cyanocobalamin is a synthetic, stable form widely used in supplements and fortified foods, whilst methylcobalamin is a naturally occurring, bioactive form found in animal products
Effects of glutamate positive modulators on cognitive deficits in schizophrenia: a systematic review and meta-analysis of double-blind randomized controlled trials
Biol Psychiatry 46 : 16241633 Doherty MD, Gratton A
Disser NP, Sugg KB, Talarek JR, Sarver DC, Rourke BJ, Mendias CL
Epidemiology: High levels of vitamin B12 were found in: Causes: Excessive supplementation (a direct increase in plasma vitamin B12 by excess intake or administration) Increased release of vitamin B12 from tissue stores (liberation from an internal reservoir): Solid tumors (especially hepatic or hematologic malignancies) Liver metastases Increased binding proteins: 7 Excess production: Liver disease (e.g., hepatitis, cirrhosis, hepatocellular carcinoma) damaged hepatocytes release haptocorrin (transcobalamin I) and B12 into circulation Myeloproliferative disorders these increase granulocyte production, which leads to more haptocorrin (transcobalamin I/III), a B12-binding protein produced by proliferating myeloid cells
