Blair K A
Nurse Pract. 1986 Jul;11(7):19-26, 31-6.
Almost one-third of American adults regularly take vitamins and supplements. If taken incorrectly or in excess, these vitamins may be a potential health hazard. Vitamins are essential nutrients which, in combination with other nutrients (e.g., fats, carbohydrates and proteins), foster normal metabolism. Vitamins also interact with each other. For example, vitamin C participates in the metabolism of folic acid, and vitamin E facilitates the absorption and storage of vitamin A. Because the biological functions of vitamins are interrelated, a diet poor in vitamins, carbohydrates, fats and proteins is not necessarily enhanced by vitamin supplementation. When vitamins are taken in excess of the Recommended Dietary Allowances or the individual's needs, the vitamins no longer function as vitamins but instead act as drugs, with such pharmacological effects as clinical toxicities and the abnormal utilization of vitamins. There are six categories that require vitamin supplements and, in some cases, megadoses. These will be discussed in detail. In addition, a brief table showing the Recommended Dietary Allowances will be given which the nurse practitioner can use in assessing nutritional needs of the client so that necessary adjustments can be made. Finally, a brief review of the potential risks and benefits of megadoses in normal, healthy adults will be given.
近三分之一的美国成年人经常服用维生素和补充剂。如果服用不当或过量，这些维生素可能会对健康构成潜在危害。维生素是必需营养素，与其他营养素（如脂肪、碳水化合物和蛋白质）结合，促进正常新陈代谢。维生素之间也会相互作用。例如，维生素C参与叶酸的代谢，维生素E促进维生素A的吸收和储存。由于维生素的生物学功能相互关联，维生素补充剂不一定能改善缺乏维生素、碳水化合物、脂肪和蛋白质的饮食。当维生素的摄入量超过推荐膳食摄入量或个人需求时，维生素就不再发挥维生素的作用，而是起到药物的作用，产生诸如临床毒性和维生素异常利用等药理作用。有六类人群需要补充维生素，在某些情况下还需要大剂量补充。这些将详细讨论。此外，还将给出一个简短的推荐膳食摄入量表格，执业护士可用于评估客户的营养需求，以便进行必要的调整。最后，将简要回顾大剂量维生素对正常健康成年人的潜在风险和益处。
