Vitamin B-12 is required for the production of hemoglobin in red blood cells,
maintenance of myelin sheath surrounding nerves (which is important for normal nerve cell
activity), and is important for the synthesis of DNA and RNA.
Vitamin B-12 works with folic acid to support normal homocysteine levels. Normal levels
of homocysteine, an amino acid metabolite supports heart and circulatory health.
Vitamin B-12 stimulates growth in children, and stimulates the utilization of proteins,
fats, and carbohydrates. It is also required for production of choline, and methionine, an
B-12 is unique in that it is the only vitamin that contains an essential mineral,
cobalt. Cobalt is thereby needed to make B-12 and as such is essential for health.
Intestinal absorption of vitamin B-12 is dependent on a substance made in the stomach
called intrinsic factor. Production of the compound decreases with age, making the elderly
at risk for B-12 deficiency and anemia. Stress and stomach surgery also weaken the body's
ability to produce the intrinsic factor. Hydrochloric acid helps the absorption of B-12,
therefore absorption is diminished when acid production is reduced.
Vitamin B-12 supports energy levels. While there is limited support that they work,
B-12 injections have been a common practice for the treatment of fatigue. There are
various contributors to fatigue. As we age, the digestive and absorptive processes are not
as efficient as when we are young. This can greatly contribute to a vitamin B-12
In older people, B-12 has been used for psychological symptoms, including senile
psychosis. It has also been used for other symptoms including fatigue, nervousness,
irritability, insomnia, memory problems, depression, and poor balance.
Vitamin B-12 is not found in the vegetable foods except for foods fermented by certain
bacteria. Vegans, strict vegetarians that consume no animal source foods may not get
adequate vitamin B-12 from dietary sources. The body stores vitamin B-12 so it typically
will take several years for a deficiency to develop.
With B-12 deficiency, the body forms large, immature red blood cells, resulting in an
anemia called pernicious anemia. It is characterized by fatigue and weakness. Most
commonly, B-12 deficiency impacts red blood cells, energy level, state of mind, and
nervous system. Initial symptoms typically start in the nervous system. Vitamin B-12
nourishes the myelin sheathes surrounding the nerves, which help maintain normal nerve
impulses. If left unchecked, the problems related to the nervous system can lead to
permanent damage. More severe pernicious anemia can progress to nerve or brain and spinal
cord degeneration, which can result in weakness, numbness, tingling, shooting pains, and
diminished reflex response.
Psychological symptoms may include mood changes with mental slowness and sensory
hallucinations. Paranoid symptoms may also occur.