[Advance and perspective of clinical nutrition]

Although nutritional support using nutrient enemas was recorded almost 3,500 years ago, the modern era of clinical dietetics commenced with the development of intravenous hyperalimentation by Dudrick et al. and the development of the chemically defined diet by Greenstein et al. Thereafter, clinical nutritional support became widely accepted as one of the basic tools of patient care, and knowledge of the metabolism of nutrients has been extended. In particular, the significance of micronutrients in systemic function, importance of gut function on the systemic metabolism and immune system, and involvement of amino acids and fat elements in the development and amelioration of specific disease status such as renal and hepatic failure have been recognized, and specific nutritional support has been created as a treatment strategy. In addition to knowledge of renal and hepatic failure or metabolic disorders, accumulated information on tumor metabolism and pathophysiology in cancer cachexia has also enabled cancer treatment using a nutritional approach. An enteral diet containing certain amino acids such as arginine or glutamate, omega-3 unsaturated fatty acids, and nucleic acids has been developed, and its clinical application under the new concept of "immunonutrition" has demonstrated reduction of the incidence of infection and shortening of hospital stay. Many questions on Immunonutrition remain to be answered such as its mechanism or optimal composition, although it is a promising field for future evolution. Currently, the assessment of nutritional status and gut function is required through lifelong education of medical doctors as well as the popularization of nutritional support teams. In the near future, tailor-made nutritional support will be required based on gene polymorphisms.