Vitamin B12 - what is it?
Vitamin B12 (Cyanocobalamin), New RDA* 2.5 µg
Vitamin B12 is a water-soluble vitamin. If you eat meat, fish or dairy foods then you should be able to get enough vitamin B12 from your diet.
However, because vitamin B12 isn't found in vegetable foods (such as fruit, vegetables and grains), vegans might not get enough of this vitamin and become deficient.
Vitamin B12 originates from bacteria, fungi and algae, and is present in virtually all animal tissues. Plants contain no vitamin B12 beyond that derived from microbial contamination
*Sourced from EFSA WEBSITE
Vitamin B12 - what does it do?
Important for making red blood cells and to keep the nervous system healthy.
Also helps to release energy from food.
Vitamin B12 serves as a cofactor to at least two enzymes, methionine synthase and methylmalonyl CoA mutase. Methionine synthase is pivotal in one-carbon metabolism, being crucial in the synthesis of the universal methyl donor S-adenosyl methionine and in the cellular import and metabolism of folate. Methylmalonyl CoA mutase converts L-methylmalonyl CoA to succinyl CoA and is important in even-chained fatty acid synthesis.
Deficiency
Dietary deficiency is rare in younger people living in the community but occurs more frequently in older people, particularly those living in institutional environments. Individuals adhering to vegan diets may also be at risk. Deficiency is mostly attributable to inherited or acquired defects resulting in malabsorption or the impairment of transport of the vitamin within the body.
Deficiency impacts on the haematopoietic and nervous systems. Associated diseases include megaloblastic anaemia and neuropathies typically sub-acute combined degeneration of the spinal cord. Vitamin B12 deficiency can lead to moderate hyperhomocysteinaemia, a possible risk factor for occlusive vascular disease.
Oral supplements are indicated prophylactically where there is a likelihood of deficiency in those whose gastrointestinal function is normal e.g. in individuals who are strict vegetarians. Inherited and acquired disorders relating to vitamin B12 malabsorption are usually treated by repeated injection. However, oral administration of very high doses of vitamin B12 has been shown to be effective in the treatment of pernicious anaemia.
Vitamin B12 - Sources
Meat, fish, milk, cheese, eggs, yeast extract and fortified breakfast cereals.
