Because vitamins do not form a coherent group, this term includes a number of different conditions with different causes. Vitamin deficiency is by no means always the consequence of inadequate nutrition. Two principal groups should be distinguished: vitamins soluble in fat (A, D, E and K) and those soluble in water (the rest). The following is a brief list of some important vitamins, the food source, and the cause and consequences of a possible shortage. Vitamin A occurs in animal products (cod liver oil, milk, butter) but mainly in vegetable matter (greens, root vegetables, tomatoes) in the form of a pro-vitamin, carotene, which the body can convert. Shortages occur through poor diet. Symptoms in mild cases are night blindness and dry skin. Severe cases cause serious eye conditions (conjunctival dehydration) and skin conditions (dehydration and callus formation). Vitamin B consists of 4 groups (vitamin B complex): vitamins B(, B2, Bh and B,:. Vitamin Bi (thiamine) occurs in liver, kidneys, wholemeal grain products, pulses and lean meat. Shortage causes beriberi, with characteristic nerve inflammation and heart weakness. Vitamin B2 is contained in among other things milk and other dairy produce, green vegetables and liver. Deficiency causes cracks in the corner of the mouth, ophthalmia, excessive sensitivity to light (photophobia), sometimes oedema and difficulties in swallowing. Shortage of vitamin B causes no distinct symptoms, but anaemia can occur in certain cases. Vitamin B,: is found in meat, milk and liver. Deficiency usually occurs through shortage of ‘intrinsic factor’ in the gastrointestinal tract, which means that the vitamin cannot be absorbed. This condition, known as pernicious anaemia, often occurs after stomach resection, because the vitamin is produced there. Treatment is by injection; oral treatment is effective only in association with intrinsic factor. Vitamin C occurs in fresh vegetables, citrus fruits, tomatoes and paprika. Deficiency is almost always the result of an inadequate diet. Symptoms include bleeding of the gums and poor healing of wounds. Severe cases lead to scurvy. Vitamin D is contained in liver, egg yolks and butter. At the same time it can be formed in the skin by the effect of UV light. The vitamin is needed for calcium metabolism, and is thus involved in bone formation. Vitamin D deficiency causes poor calcification of growing bones in children, and thus rickets, with thickening at the growth discs and crooked bones, especially at the end of the calf bones. In adults decalcification sets in, and thus weakening of the bones (osteomalacia), with additional muscular weakness and listlessness. Treatment is by considerable quantities of the vitamin. There is much propaganda for giving children vitamin D in the winter, but the usefulness of this procedure is still in some doubt.