A 'nutrient' (NOO-tree-unt) is a substance you get from food. It's used by the body for growth, maintenance, or repair of tissues. There are six categories of nutrients: proteins, carbohydrates, fats and oils, vitamins, minerals, and water. Water is the most abundant nutrient in the body, a component of every cell, and accounting for 60 percent of body weight. Proteins are used primarily in the growth and maintenance of lean body tissues, the muscles. Protein is formed from building blocks called 'amino (uh-MEE-no) acids. There are around 22 different kinds of amino acids, which combine to form billions of varieties of proteins. 'Essential' nutrients are substances the body is unable to make on its own and must be obtained from food. These include up to ten amino acids, most of the 13 vitamins, 15 to 20 minerals, and an oil called linoleic (lin-oh-LAY-ic) acid. The term 'essential' means not only 'necessary'-- because other nutrients also are necessary-- but also that the body is dependent on diet as a source of the nutrient. Intake levels for essential nutrients are suggested through the Recommended Dietary Allowances, or 'R-D-A's' of the National Academy of Science. The N-A-S currently is updating its information concerning how it sets reference values for all nutrients. The new title will be 'Dietary Reference Intakes,' or 'D-R-I's.
©2006 Crossroads Mobile. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
