Volume 11 Part 2 Article 14: Vitamin B12 in Substrates and Fruitbodies of Agaricus bisporus

Volume 11 Part 2 Article 14
Year 1981
Title: Vitamin B12 in Substrates and Fruitbodies of Agaricus bisporus
Authors: W.A. Hayes and P. Hand

Abstract:

Up to the beginning of this century it was believed that only proteins, fats, carbohydrates and minerals were required in a balanced diet. During the early part of this century it was recognised that animals and man require small amounts of other dietary factors which were called “vital amines” or vitamins. A range of different vitamin compounds were discovered, but it was not until the end of the first half of this century that vitamin B12 was discovered (Smith, 1948; Rickes et al., 1948).

The human dietary requirement for vitamin B12 is very small; the World Health Organisation (1974) for example, recommend an intake of 1µg per day. The main sources of dietary vitamin B12 are the tissues and products of animals, practically all of which contain the vitamin (Holman, 1956). Vegetable or plant foods contain no appreciable amounts (Robbins et al., 1950) and this is of significance to vegetarians. Deficiency of the vitamin causes pernicious anaemia and is sometimes associated with a subacute degeneration of the spinal cord.

Although the vitamin B12 content of foodstuffs has been studied extensively, edible fungi and A. bisporus in particular have not been considered as sources of vitamin B12. Since a mushroom compost is usually prepared from horse manure which is known to be rich in the Vitamin (Miller and Groschke, 1950) and many of the micro-organisms involved in composting (Hayes, 1968; Stanek, 1968) are able to synthesise the vitamin, an investigation into the content of vitamin B12 in mushroom substrates and fruitbodies of A. bisporus was justified.

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