Cobalamin

Vitamin B12, also known as cobalamin, is a water-soluble vitamin, one of the B vitamins. Forms of cobalamin include hydroxo-cobalamin, cyano-cobalamin, methyl-cobalamin, and adenosyl-cobalamin.

Physiology
B12 is involved in cellular metabolism and formation of red blood cells (RBCs). It has an integral role in brain and nervous system function. Absorption of B12 from dietary sources requires an intrinsic factor (IF or GIF), i.e., a glycoprotein, synthesized in and secreted from parietal cells in the lining of the human stomach.

Immune system
Vitamin B12 deficiency may be associated with decreased natural killer cell activity.

Notable studies

 * 2000, Cobalamin Used in Chronic Fatigue Syndrome Therapy Is a Nitric Oxide Scavenger (Abstract)
 * 2015, Response to Vitamin B12 and Folic Acid in Myalgic Encephalomyelitis and Fibromyalgia (Full Text)

Learn more

 * Linus Pauling Institute Micronutrient Information Center - Vitamin B12
 * B12 - rationale for using vitamin B12 in CFS - Dr. Sarah Myhill