The carbohydrates are the main source of energy giving food for the people of the world. Through the process of photosynthesis, the chlorophyll of the plants is able to use the solar radiations to synthesize carbohydrates from the carbon dioxide of the air, and the water from the soil.
These are classified as Monosaccharide, Disaccharides and Polysaccharides.
Glucose, Fructose, Galactose.
Maltose, Lactose, Sucrose.
All the carbohydrates contain carbon, hydrogen and oxygen. The polysaccharides and disaccharides taken as food get composed the monosaccharide, usually glucose.
This in fact is the basic component of providing energy to the body for various functions. Excess of carbohydrates get stored in the liver and muscles as glycogen which can be quickly changed into energy when need arises.
Important Functions of Carbohydrates
As a Source of Energy:
One gram of carbohydrate gives 4 calories of energy on burning. The consumption of carbohydrates is usually greater than that of fat.
Liver and muscle glycogen reserves provide a constant interchange with the body’s overall energy balance system and protect cells from depressed metabolic function and injury.
Protein Sparing Action:
Carbohydrates are mainly used upon for providing energy, thereby sparing the proteins for body building functions.
The deficiency in calorie requirement in the diet is made up by using adipose tissues and protein tissues. Primary psychological demand is that energy and that must invariably be fulfilled by carbohydrates or fats before other nutrient proteins are used-up for other functions.
Regulation of Fat Metabolism:
For normal oxidation of fats, the inclusion of carbohydrate is drastically restricted in the diet; fats will be metabolized mush faster than the body can take care of the intermediate products. For complete oxidation of fats to the metabolic end products of carbon dioxide and water, an organic acid called pyruvic acid is required.
In this process ketone bodies are produced in large amount and these ketone bodies in the blood increase its acidity, resulting in a condition called ketosis. Ketosis may result in diabetes where the cells can not consume carbohydrates. It also occurs during starvation and fasting where the cells have to use the fat of body for its requirement of energy.
The carbohydrates play an important role in the gastro-intestinal functions of mammals. They serve as a source of energy for the micro-organisms that synthesize some B-complex vitamins in the intestinal tract and the cellulose provides fiber and bulk that promote healthy intestinal hygiene.
Heart functioning is a life sustaining execercise. The fatty acids are the preferred fuel of the heart muscles but the glycogen in the cardiac muscles but the glycogen in cardiac muscles is an important source of contractile energy. In a damaged heart, poor carbohydrate intake may cause cardiac disorders or angina.
Central Nervous System:
Central nervous system requires constant supply of glucose from the blood as brain does not contain stored glucose. Sustained and profound hypoglycemia may cause irreversible brain damage.
Food Sources of Carbohydrates
The sugars, cereal grains, legumes and dried fruits are the richest sources of carbohydrates. The sugar is almost pure carbohydrate, but cereal grains, legumes, and dried fruits may differ in their carbohydrate contents.
Although most fresh fruits and vegetables are low in carbohydrates, but some fruits and vegetables like bananas, dates, white potatoes and sweet potatoes are rich in this nutrient.