This article is about carbohydrates. It describes about the sources of carbohydrates in our food, types of carbohydrates i.e. monosaccharides, disaccharides and polysaccharides and the functions of carbohydrates in our body.


Carbohydrates are the most abundant organic compounds that are found in nature. They are found in many foods like sugar, jam, beans, potatoes, cereals, bread, biscuits, pasta, fruit and vegetables. As the name suggests, carbohydrates are made of carbon, hydrogen and oxygen, with hydrogen and oxygen present in the same proportion as in water. On the basis of the chemical complexity, carbohydrates are further classified as monosaccharides, disaccharides and polysaccharides.

These are the simplest forms of carbohydrates. Examples of monosaccharides are glucose, fructose and galactose. These are made up of single units or molecules which if broken down further would not yield sugar molecules. It is in the form of monosaccharides that the body absorbs carbohydrates after their digestion in the alimentary canal.

As the name suggests, disaccharides are sugars that are made of two monosaccharide molecules. Common examples of disaccharides include sucrose, maltose and lactose. Other examples are trehalose which is found in fungi and insects and cellobiose.

Polysaccharides are relatively complex carbohydrates. They are polymers made of complex molecules which in turn are made of a large number of monosaccharide molecules that are in chemical combination. Examples of polysaccharides include starch, glycogen, cellulose and dextrins.
Human beings cannot digest all of the polysaccharides. For example, cellulose present in vegetables, fruit and some cereals is not digested and so is passed through the alimentary canal unchanged.

Functions of digestible carbohydrates
The main functions of carbohydrates in the human body are
Providing energy and heat
Protein sparing
As a means of storing energy.

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