1.1 Background of the Study
The process of nourishing or being nourished especially the process by which a living organism assimilates food and uses it for growth and for replacement of tissues is known as nutrition. (Don MacKean 2004). Green plants are the most important food producer that produces their food through the process of photosynthesis and mineral uptake (Spring 2002). Food is made up of different nutrients needed by the body for healthy growth and development. Many kind and combinations of nutrients in the food at an appropriate content or quantity leads to a well-balanced diet. Each of these nutrients have a specific use in the body (Akinfasoye, 2005).
Man (like other animals) also takes in food produced by the plants and the food are used in three practical ways which are; for energy, growth and replacement of damaged tissues. During respiration, food is broken down to produce energy for movement and essential chemical reactions, contributes to the growth of cells and tissues e.g. red blood cell and the cells of the epidermis (Delvin, 2002) using the protoplasm made by the food. Food also helps to repair wounds and other damaged body structure (Adeleye, 2005). For food to perform all these functions, it must contain the substances that can meet all requirements (chemical materials) which are protein, fats, carbohydrate, water, salts, vitamins and roughages.