vitamin B12 is a water soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in the metabolism of every cell of the body, especially affecting DNA synthesis and regulation, but also fatty acid synthesis and energy production.
According to the U.K. Vegan Society, the present consensus is that any B12 present in plant foods is likely to be unavailable to humans and so these foods should not be relied upon as safe sources, as the B12 analogues can compete with B12 and inhibit metabolism. Also, vegan humans who eat only plant based foods must ordinarily take special care to supplement their diets accordingly. The only reliable vegan sources of B12 are foods fortified with B12 (including some soy products and some breakfast cereals), and B12 supplements.
According to the U.K. Vegan Society, the present consensus is that any B12 present in plant foods is likely to be unavailable to humans and so these foods should not be relied upon as safe sources, as the B12 analogues can compete with B12 and inhibit metabolism. Also, vegan humans who eat only plant based foods must ordinarily take special care to supplement their diets accordingly. The only reliable vegan sources of B12 are foods fortified with B12 (including some soy products and some breakfast cereals), and B12 supplements.