Introduction – Nutrition in Man


The human digestive system is a complex system involving ingestion, digestion, absorption and assimilation of the food we eat. The digestive system starts at the mouth and ends at the rectum. Each stage of the system has its own unique function; these functions are listed below:

Ingestion- this is the intake of food into the body

Digestion- this is the breaking down of food into smaller units so that it can be absorbed.

Absorption- this is the uptake of soluble digested food into bodily fluids, such as blood.

Assimilation- this is the incorporation of absorbed food into the cells of the body.

Types of food we eat
Proteins (meat, eggs, milk) – These are made of polypeptide chains – which are in turn made from amino acids.

Starches- These are made of polysaccharide chains which are in turn made of monosaccharide like glucose

Simple sugars- These are monosaccharide and disaccharides such as glucose, maltose and sucrose (sugar we use on a daily basis).

Vitamins- These are essential organic compounds needed for the body to function properly.

Minerals- These are elements needed for the body to function properly.

Water- The human body is about 55-60% water. Water is a vital solvent and transport medium for many minerals and salts needed by all the cells of the body.


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