Vitamin requirements: present recommendations and future prospects

Dietary recommendations evolved from instructions directed at prevention of starvation diseases to the level of intake of essential nutrients that are adequate to meet the known nutrient needs of practically all healthy persons. Vitamin requirements have been modified various times over the years and there are still differences in recommended intakes in different countries. A debate on optimal vitamin intake is ongoing, based on the concepts of deficiency, sufficiency and hypothetical identification of a range within which a further biological advantage can be expected. In establishing appropriate criteria for food and nutrient intakes, additional studies are warranted on the physiological interactions between nutrients and non-nutrients and on many other factors such as genetic determinants and lifestyle which could interfere with disease prevention.