CARBOHYDRATES

Carbohydrates are compounds of carbon, hydrogen and oxygen. Accoding to the structural complexity of the molecule, carbohydrates are classified into monsacchrides, disacchrides and polysaccharides.

Monosaccharides (simple sugars): These include fructose (fruit sugar) and glucose, often called blood sugar because it's what all carbohydrates are broken down into in the body. Only glucose circulates in the blood, providing energy to organs, glands, muscles, indeed to every cell. Finally, there is galactose, which rarely stands alone but does combine with other simple sugars, notably with glucose to form lactose (milk sugar).

Disaccharides (double sugars): Nothing more than bonded pairs of simple sugars. There is sucrose (table sugar), glucose plus fructose; lactose (milk sugar), glucose plus galactose; and maltose (malt sugar), two linked glucose molecules.

Polysaccharides (complex carbohydrates): Elaborate chains of glucose molecules, which from a nutritional standpoint are far and away the most important because they digest more slowly than simple or double sugars. Found in peas, beans, grains, potatoes and other starchy plants, they come freighted with DIETARY FIBER, VITAMINS and MINERALS.

Function

Carbohydrates are the main source of energy in the body. One gram of carbohydrate can provide seventeen kJ of energy. Glucose is used in oxidation. More complex sugars have to be changed to glucose first before they can be broken down to release energy in respiration.

Dietary fibre gives bulk to the food and stimulate peristalsis along the alimentary canal. This can prevent constipation.

Sources