The Vitamin B12 plays a vital role in the normal functioning of the brain and the nervous system and in the formation of red blood cells. It also helps to regulate and synthesize DNA. It is needed in the metabolism of every cell in the body, and it plays a part in the synthesis of fatty acids and energy production. By helping the human body to absorb folic acid, it facilitates the release of energy.

B12 also supports myelin, which allows nerve impulses to conduct, and when this vitamin is deficient, it's been suspected to drive symptoms for diseases such as dementia, impaired gait, sensation, and multiple sclerosis. Clinically, B12 may be best-known for its role in red blood cell production. Deficiency states may result in pernicious anemia. But what about B12's role in psychiatric symptoms such as depression, anxiety, fatigue, and even psychosis?

The one-carbon cycle refers to the body's use of B vitamins as "methylators" in DNA synthesis and the management of gene expression. There are three concepts that relate to B12's role in chronic, long-latency neuropsychiatric syndromes:

Methylation

This process of marking genes for expression, like little "read me!" signs, is also critical for detox and elimination of chemicals and hormones (estrogen), building and metabolizing neurotransmitters, and producing energy and cell membranes.

Homocysteine recycling

B12 is a primary player in the one-carbon cycle and a co-factor for the methylation, by activated folate, of homocysteine, to recycle it back to methionine. From there, SAMe is produced, the body's busiest methyl donor.

Genetic override

Sufficient supply of an activated/bioavailable form of a vitamin (ie methylfolate vs folic acid) is even more necessary in the setting of gene variants such as transcobalamin II, MTHFR, and MTRR which may function less optimally in certain individuals and result in pathology under stress. An example of this is a report of death in a B12-deficient patient with genetic variants who underwent anesthesia with nitrous (which causes stress to the system). Notably the B12 blood level was normal, so this fatal case was attributed to functional deficiency, suggesting that access to B vitamins may not always guarantee proper utilization. For this reason, supplementing with activated forms of B vitamins enhances their likelihood of effectively supporting cellular processes.

"Depression, dementia and mental impairment are often associated with" a deficiency of B12 and its companion B vitamin folate, "especially in the elderly," Dr. Rajaprabhakaran Rajarethinam, a psychiatrist at Wayne State University School of Medicine, has written.

He described a 66-year-old woman hospitalized with severe depression, psychosis and a loss of energy and interest in life who had extremely low blood levels of B12 and whose symptoms were almost entirely reversed by injections of the vitamin