Carbohydrate Health Dictionary

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Carbohydrate: From 2 Different Sources

The term applied to an organic substance in which the hydrogen and oxygen are usually in the proportion to form water. Carbohydrates are all, chemically considered, derivatives of simple forms of sugar and are classi?ed as monosaccharides (e.g. glucose), disaccharides

(e.g. cane sugar), polysaccharides (e.g. starch). Many of the cheaper and most important foods are included in this group, which comprises sugars, starches, celluloses and gums. When one of these foods is digested, it is converted into a simple kind of sugar and absorbed in this form. Excess carbohydrates, not immediately needed by the body, are stored as glycogen in the liver and muscles. In DIABETES MELLITUS, the most marked feature consists of an inability on the part of the tissues to assimilate and utilise the carbohydrate material. Each gram of carbohydrate is capable of furnishing slightly over 4 Calories of energy. (See CALORIE; DIET.)

Health Source: Medical Dictionary
Author: Health Dictionary
n. any one of a large group of compounds, including the *sugars and *starch, that contain carbon, hydrogen, and oxygen and have the general formula Cx(H2O)y. Carbohydrates are important as a source of energy: they are manufactured by plants and obtained by animals from the diet, being one of the three main constituents of food (see also fat; protein). All carbohydrates are eventually broken down in the body to the simple sugar *glucose, which can then take part in energy-producing metabolic processes. Excess carbohydrate, not immediately required by the body, is stored in the liver and muscles in the form of *glycogen. In plants carbohydrates are important structural materials (e.g. cellulose) and storage products (commonly in the form of starch). See also disaccharide; monosaccharide; polysaccharide.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Carbohydrates

A group of compounds composed of carbon, hydrogen, and oxygen, which supply the body with its main source of energy. Carbohydrates are found in fruits, cereals, and root crops and fall into 2 groups. These are available carbohydrates, which are metabolized into glucose for the body’s use, and unavailable carbohydrates, such as cellulose, which cannot be broken down by digestive enzymes and make up the bulk of dietary fibre (see fibre, dietary).

Available carbohydrates are predominantly starches (complex carbohydrates) and sugars (simple carbohydrates). In carbohydrate metabolism, the monosaccharides (simple sugars) glucose (grape sugar), galactose (a milk sugar), and fructose (fruit sugar) are absorbed into the bloodstream unchanged. The disaccharides (double sugars) sucrose, maltose and lactose (a milk sugar) are broken down into simple sugars before they are absorbed. Starches also have to be broken down into simple sugars.

Some glucose is burned up immediately (see metabolism) in order to generate energy for cells, such as brain cells, that need a constant supply. Galactose and fructose have to be converted to glucose in the liver before they can be used by body cells. Surplus glucose is conveyed to the liver, muscles, and fat cells where it is converted into glycogen and fat for storage. When blood glucose levels are high, glucose storage is stimulated by insulin, a hormone that is secreted by the pancreas. When the blood glucose level becomes low, insulin secretion diminishes and glucagon, which is another hormone produced by the pancreas, stimulates the conversion of stored glycogen to glucose for release into the bloodstream. Although fat cannot be converted to glucose, it can be burned as a fuel in order to conserve glucose. In the disorder diabetes mellitus, carbohydrate metabolism is disturbed by a deficiency of insulin.... carbohydrates


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