Vitamin B12 is a complex substance containing the mineral colbalt at its centre. Principally, it participates in the rapid regeneration of bone marrow and red blood cells. This vitamin was first isolated from liver in 1948 and is needed for the synthesis of DNA and for normal metabolism of nerve tissue. However, in cases of achlorhydria (absence of hydrochloric acid in the stomach) the vitamin may not be extracted from food. Folic acid, iron and vitamin B12 are all referred to as haematinic factors and are vital for the formation of healthy blood cells. Vitamin B12 is also necessary for myelin sheath production and for a healthy cardiovascular system. Vitamin B12 is found mainly in animal based foodstuffs such as meat. Consequently, practitioners frequently recommend this particular B vitamin to vegetarians and vegans. It is also often recommended as a supplement for the elderly, who may have a compromised diet. These small, easy to swallow tablets provide a full 1000µg of vitamin B12. They are made in the UK and produced in premises that operate to stringent pharmaceutical standards of GMP. Use of 1000µg of vitamin B12 requires specialist knowledge.