Types of Nutrition
The food contains a number of organic and inorganic constituents to meet the requirements of the body. These food constituents must be digested to be utilized by the body. The process by which organisms obtain and utilize food for their growth, development and maintenance is called nutrition and the chemical constituents present in the food are called nutrients.
Digestion is the breaking down of complex constituents of food by enzymes into simpler soluble forms that can be absorbed and utilized by the cells of the body.
Types of Nutrition
There are mainly two types of nutrition:
- Autotrophic Nutrition
- Heterotrophic Nutrition
Five Major Steps in Animal Nutrition (Holozoic nutrition)
The food contains highly complex nutrients like protein, carbohydrates and fats. These substances cannot be utilized as such by the body. These have to be broken down into simpler and smaller molecules before they can enter into the cells. Proteins must be broken down into amino acids, carbohydrates into glucose, fats into fatty acids and glycerol.
Amino acids, glucose, fatty acids and glycerol are simpler substances, and can be directly utilized by the body. This breakdown of complex food constituents and their absorption is accomplished by the digestive system. The processes involved in nutrition are:
- Ingestion: Taking in food, chewing or sucking it and swallowing.
- Digestion: Conversion of complex food into simpler absorbable form.
- Absorption: Absorbing digested food from the gut to reach the body tissues.
- Assimilation: Utilization of digested food nutrients by the body tissues.
- Egestion: Removal of undigested and unabsorbed food from the body.