Clinical nutrition is the study of the relationship between food that is consumed and the health and well-being of the body. The field of clinical nutrition considers the way the body uses the nutrients found in foods and supplements, as well as the way the body processes the nutrients and then stores them for later use or eliminates them. Clinical nutrition also considers other contributing factors to health, such as the environment, family history, and overall well-being when trying to determine an individual's nutrient needs.
Clinical nutrition was first developed in the early 1900s, when scientists discovered that some diseases, such as beri-beri or scurvy, seemed to be caused by specific diets that were fairly limited in the amount of foods consumed. By 1912, Casimir Funk, a Polish biochemist, had discovered that eating brown rice seemed to prevent beri-beri. He set out to discover what substance was found in brown rice that would cause this, and discovered Thiamine, which he referred to as a "vitamine" because it contained an amine group. This would later come to be known as vitamin B1, and Funk correctly theorized that other diseases could be prevented with vitamins as well.
Scientists and nutritionists continue to evaluate the nutrients found in the healthiest diets to try to determine the minimum nutritional needs of individual people. Recommended Daily Allowances (RDAs) are the product of these studies, and illustrate in a basic way what people should try to eat every day. Dietary Reference Intakes (DRIs) attempt to illustrate the amount of nutrients that should be included in the diet for the purpose of disease prevention and treatment. A combination of these two recommendations generally supplies a complete picture of the foods and nutrients that will constitute a healthy diet.
Clinical nutrition also often references macronutrients and micronutrients. Macronutrients include carbohydrates, proteins, and fats, and are used for energy in the body as well as the maintenance of cells and tissues. Micronutrients include vitamins and minerals, and they assist the body in breaking down macronutrients for energy by triggering chemical reactions. Macronutrients constitute the majority of the diet, whereas micronutrients are a much smaller portion of the diet. Most nutrients needed by the body must work in conjunction with other nutrients to achieve any effect; this is why it is important to eat a healthy diet, and not to simply rely on nutritional supplements, as scientists have yet not discovered all of the ways in which nutrients work together.
In general, people who eat a healthy, balanced diet, take a multivitamin, and who do not have any underlying medical conditions are able to meet their nutritional needs without any extra help. If anyone is concerned about their diet, however, a visit to a clinical nutritionist can help get them back on the right track. The nutritionist will assess their overall health and eating habits through a series of questions regarding lifestyle, medical history, and family history, as well as laboratory tests. The nutritionist will then be able to develop a healthy eating plan customized just for them, which often includes other recommendations for a healthy lifestyle, such as exercise.