Fat Soluble and Water Soluble Vitamins
Vitamins can be defined as essential organic micronutrients that are involved in fundamental functions of the body, such as growth, maintenance of health and metabolism. Because of these substances must be supplied wholly or partially by the diet. Although the clinician should be able to recognize the syndrome caused by a lack of the vitamin in the case of a deficiency, it is more relevant in this country of abundant and varied food supply for the nutrition professional to think in terms of what a specific vitamin does rather than what disease it [prevents. Unfortunately, at the present time it is often impossible to relate directly the function of the vitamin to its deficiency syndrome.
Vitamins for the most part are not related chemically and differ in their physiologic roles. The broad classifications of water soluble vitamins and fat soluble vitamins are made because of certain properties common to each group. For instance, absorption and transport of fat soluble vitamins are closely associated with the absorption and transport of lipids; optimal absorption requires the presence of bile slats, these vitamins can also be stored in body lipids, although the amounts stored varies widely among the four fat soluble vitamins.
The water soluble vitamins are handled quite differently by the body. Their absorption requires no formation of micelles and with the exception of cyanocobalamin (vitamin B12), they cannot be retained by the body for long periods. Any storage occurring, results from their binding to enzymes and transport proteins. Water soluble vitamins are excreted in the urine wherever plasma levels exceed renal thresholds.
Fat Soluble and Water Soluble Vitamins