CARBOHYDRATES
( Sources of Enegy )
To carry on life processes, the cells of your body need energy. Most of this energy comes from Carbohydrates. Common natural sources of the
CARBOHYDRATES are sugar, fruits, vegetables, bread, pastries, spaghetti, macaroni, noodles, rice, rye, and barley. In many countries much carbohydrates is obtained by using refined
sugar in foods such as jellies, jams, preserves marmalade, and candy, as well as by eating honey, molasses and syrup.
When carbohydrates are consumed or ‘’burned’’ in your body, energy is released. This energy is eventually converted into heat. We measure this heat in units called calories. A’’small calorie’’ is the amount of heat required at a pressure of one atmosphere ( about 14.7 pounds per square inch ) to raise the temperature of one gram of water one degree centrigrade. A’’large calorie’’ is equal to 1,000 small calories. To measure the energy-producing value of food, we use large
calories as units. They are reffered to only as calories,’’large’’ being understood.
Carbohydrates are compossed solely of carbon, hydrogen and oxygen. They have the general
formula C2H2yOy . For example, in the carbohydrate called sucrose, x=12 and y=11. If we subtitude 12 for x and 11 for y, we have C12H22O11 as the formula for sucrose.
The carbohydrates are known as saccharides, or compounds containing sugar. The simplest carbohydrates are the
monosaccharides ( single saccharides ), many of which have the general formula C6H12O6. The most important ones another; they threemost important ones are sucrose ( table sugar ), lactose ( milk sugar) and maltose ( malt sugar ). Sucrose is formed from a molecule of
glucose and one the fructose; lactose, from one glucose molecule and one of galactose; maltose, from two glucose molecules.
The most complex carbohydrates of all are the polysaccharides (‘’many saccharides’’ ). They consist of a number of units, which are either monosaccharides or derivatives of monosaccharides. The polysaccharides are comparatively tasteless and insoluble. They include strach,
glycogen and cellulose, which all have the general formula ( C6H10O5 )x. Starch is found in plants, particularly in seeds and tubers. Glycogen is similar to starch; it occurs in the muscles of animals and also in their internal organs, particularly the liver. Sellulose is an important strusctural element in plants. It forms the wall of plant cells and is found in woody materials generally.
When monosaccharides are eaten, they do not have to be broken down by our body. Disaccarides and polysaccharides, however, must be digested or broken down, to monosaccharides, before they can be absorbed. Whatever their original chemical structure may have been, therefore, the carbohydrates enter the blood as monosaccharides.
If u eat a heavy meal with large amounts of carbohydrates, the concentration of glucose in your blood rises significantly. If the concentration is too high, some of the sugar is excreted by the kidneys; since it passes out with urine, it is lost the body. Generally, however, the glucose is removed from the bloodstream before this take place. The excess is stored in the form of glycogen, or animal starch, chiefly in the liver; but also, to a certain extent, in the muscles. This glycogen represents a reserve supply of carbohydrates for your body and is drawn on between meals. If you eat an excessive amount of carbohydrate, it is converted to fat.
It is not possible to determine the minimum requirement in the case of carbohydrates, since this requirement varies widely according to the individual’s muscular activity. Generally, the requirement for other essential nutrients are first determined; then the remaining calorie requirements are made up largely from carbohydrates is supplied, the body will have to draw upon its proteins for a part of its fuel needs, with unfortunate results.
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