Benders'dictionary of nutrition and food technology

503vitamin H See biotin.vitamin K Two groups of compounds have vitamin K activity:phylloquinones (vitamin K 1 ), found in all green plants, and avariety of menaquinone (vitamin K 2 ) synthesised by intestinalbacteria. Vitamin K 3 is a synthetic analogue, menadione.Functions as coenzyme in carboxylation of glutamate to γ-carboxyglutamate in a number of calcium binding proteins,including prothrombin and other proteins involved in the bloodclotting system, the bone protein osteocalcin, and the productof the growth arrest-specific gene (Gas-6), which is important inregulation of growth and development.Dietary deficiency is unknown, except associated with generalmalabsorption diseases. However, some newborn infants are atrisk of developing haemorrhagic disease as a result of lowvitamin K status, and it is general practice to give a single relativelylarge dose of the vitamin by injection.See also anticoagulants; dicoumarol; warfarin.VITAMIN Kvitamin L Factors extracted from yeast and thought at the timeto be essential for lactation; they have not become establishedvitamins.vitamin M Obsolete name for folic acid.vitaminoids Name given to compounds with ‘vitamin-like’ activity;considered by some to be vitamins or partially to replacevitamins. Include flavonoids (vitamin p), inositol, carnitine,choline, lipoic acid and the essential fatty acids (see fatty acids,