The principally pharmacological aspects of vitamins are described nutritional aspects, physiological function, sources, daily requirements and deficiency syndromes (primary and secondary) are to be found in any textbook of medicine. • • • • Vitamin A: retinol Vitamin B: complex Vitamin C: ascorbic acid Vitamin D, calcium, parathyroid hormone, calcitonin, bisphosphonates, bone • Treatment of calcium and bone disorders • Vitamin E:tocopherol that subclinical vitamin deficiencies are a cause of much chronic ill-health and liability to infections. This idea has led to enormous consumption of vitamin preparations, which, for most consumers, probably have no more than placebo value | 38 SECTION 8 Vitamins calcium bone SYNOPSIS The principally pharmacological aspects of vitamins are described nutritional aspects physiological function sources daily requirements and deficiency syndromes primary and secondary are to be found in any textbook of medicine. Vitamin A retinol Vitamin B complex Vitamin C ascorbic acid Vitamin D calcium parathyroid hormone calcitonin bisphosphonates bone Treatment of calcium and bone disorders Vitamin E tocopherol Vitamins are substances that are essential for normal metabolism and must be chiefly supplied in the diet. Humans cannot synthesise vitamins in the body except some vitamin D in the skin and nicotinamide from tryptophan. Lack of a particular vitamin may lead to a specific deficiency syndrome. This may be primary inadequate diet or secondary due to failure of absorption intestinal abnormality or chronic diarrhoea or to increased metabolic need growth pregnancy lactation hyperthyroidism . Vitamin deficiencies are commonly multiple and complex clinical pictures occur. There are numerous single and multivitamin preparations to provide prophylaxis and therapy. It has often been suggested but never proved that subclinical vitamin deficiencies are a cause of much chronic ill-health and liability to infections. This idea has led to enormous consumption of vitamin preparations which for most consumers probably have no more than placebo value. Fortunately most of the vitamins are comparatively nontoxic but prolonged administration of vitamins A and D can have serious ill-effects. Vitamins fall into two groups water-soluble vitamins the B group and C fat-soluble vitamins A D E and K Vitamin A retinol Vitamin A is a generic term embracing substances having the biological actions of retinol and related substances which are called retinoids . The principal functions of retinol are to sustain normal epithelia form retinal photochemicals enhance immune functions protect against infections and probably some cancers. .
