Vitamin B12 is a water-soluble vitamin that is found at high levels in red meat, fish, poultry and eggs. Its structure includes a cobalt ion that gives it specialized biochemical functions. In the body, vitamin B12 is present in two forms: Methylcobalamin and 5-deoxyadenosylcobalamin. These are necessary for blood cell formation, DNA synthesis and processing, energy conversion and cardiovascular system functions.
Blood Cell Production
Vitamin B12 is necessary for the proper formation of red blood cells. Inadequate levels of vitamin B12 may lead to development of megaloblastic anemia, a condition in which the body lacks sufficient healthy red blood cells for oxygen transport. This type of anemia is characterized by larger than normal red blood cells. Patients experience fatigue, weakness, dizziness and loss of appetite. Megaloblastic anemia is often accompanied by nerve damage including numbness in the hands and feet. (See Ref 1)
DNA Synthesis
Vitamin B12 is required for the functioning of methionine synthase, an enzyme that catalyzes the formation of methionine in the body. Methionine is a building block for many other molecules in the body. One of these is S-adenosylmethionine, a methyl donor for nucleic acids including DNA and RNA.
Metabolism
Vitamin B12 plays a basic role in the breakdown of proteins and fats. As a cofactor for the enzyme L-methylmalonyl-CoA mutase, vitamin B12 assists in the conversion of L-methylmalonyl-CoA to succinyl-CoA. This biochemical reaction is of fundamental importance to metabolism and energy conversion.
Cardiovascular Health
Homocysteine is an amino acid derived from methionine. When vitamin B12 is deficient, homocysteine levels in the blood can rise due to improper functioning of methionine synthase. Elevated homocysteine has been linked to a number of adverse effects on the cardiovascular system and is associated with an increased risk of coronary heart disease and stroke.
Member Comments