FOOD AND NUT SS1 WK 10 NOTES

 Date:

Topic: BASIC FOOD NUTRIENTS 

                  Functions of Carbohydrates 

1. They serve as a source of heat and energy to the body.

2. They add bulk to the faeces thereby acting as a mild laxative by roughages or dietary fibres. 

3. They form the components of the hereditary principles e.g deoxyribonucleic acid ( DNA) 

                                PROTEINS 

              They are the main body building food substances that are necessary for building new cells and repairing worn out tissues. The enzymes and hormones found in the body are made up of proteins . They are also required in fairly large quantity in the body. They are made up of carbon, hydrogen,oxygen and some may also contain iron, sulphur and phosphorus. Proteins are also referred to as polypeptides

     On hydrolysis, protein yields simpler absorbable units called amino- acids. There are about twenty types of amino acids found in proteins. These are classified into two namely;

a. Essential amino acids:These are amino acids that cannot be produced by the body and therefore must be present in the proteins food consumed. The 9 essential amino acids includes valine, leucine,iso leucine, lysine, phenyl alanine, methionine,tryptophan, thiamine and histidine.  

b. Non essential amino acids: these are amino acids that the body can produce from other sources and therefore may not necessarily be present in the protein food consumed e.g glycine,aspartic acid, serine, asparagine etc. 

                   Functions of Proteins 

1. Promotes growth and development of the body.

2. Repairs worn-out tissues 

3. Serves as a source of energy in the absence of carbohydrates and fats.

4. Builds enzymes to catalyse chemical reactions in the body .

5. Build antibodies that fights against infection and diseases.

                          Fats and Oils 

       Fats and oils are secondary sources of energy composed of the following elements; carbon, hydrogen and oxygen. On hydrolysis, fats yields glycerol and fatty acids. Usually a molecule of glycerol may have between 1 to 3 different or same fatty acid molecule attached to it. Therefore the difference in the chemical composition of fats and oils is in the type of fatty acids contained. When one molecule of fatty acids is attached to one molecule of glycerol, the resulting fat and oil is called Monoglycerides. Excess carbohydrates and protein can be converted into fats and stored. 

 Excess carbohydrate and protein can be converted into fats and stored.

           Difference between fats and oils 

I. Fats are solids at room temperature while oils are liquid at this temperature.

II. Fats contain saturated fatty acids while oils contains unsaturated fatty acids.

III. Fats are usually obtained from animals while oils are obtained from plants.

            Fatty acids being the major compound supplied to the body can be classified into two namely; essential and non-residential fatty acids

                    Functions of Fatty acids 

1. Serves as a source of heat and energy 

2. Act as insulators thus preventing  heat loss from the body  and hence assist in maintaining  constant body temperature. 

3. Contributes to flavour and palatability of food 

4. Acts as a cushion to the delicate internal organ protecting them against shock and damage .

5. Promotes healthy hair and skin 

                             Vitamins    

       Vitamins are organic in nature but they are required in very little quantity for the normal functioning of the body. Vitamins cannot be produced by the body hence , they must be  added in our meals. They are classified into two groups;

a.water soluble vitamins; these are vitamins that can dissolve in water but not in fat & oil e.g B1, B2, B3, B6, C etc 

b. Fat soluble vitamins; they are vitamins that can dissolve in fats, oils and other organic solvent but not water e.g vitamin A,D,E,K ( Retinol, cholecalciferol, topocalciferol and phylloquinone. 

                       Mineral Element 

          Mineral elements are also required in a very minute quantity by the body. They are inorganic nutrients unlike protein, carbohydrate etc. They perform variety of functions like growth and vital metabolic activity. Mineral elements are usually classified into two groups namely 

a. Macro Element: these are required in fairly large quantity or amount by the body e.g sodium, calcium, magnesium, potassium, chlorine, sulphur and phosphorus.

b. Micro or Trace Elements; theses are required in very little quantity by the body e.g iron, copper, zinc, manganese, iodine, fluorine, cobalt.

                     Water 

       Water is the major component of life of all living things. It is very essential for the existence of plants and animals. It is made up of two elements; hydrogen and oxygen with the formular H2O. Water has no energy value. In pure form, it is colourless, odourless and tasteless. 

                         Functions of Water 

1. Water serves as the medium for biochemical reactions in the body.

2. It serves as the medium transportations of substances from one part of the body to another 

3. Keeps the lining of the membrane  of the organs moist  and hence it reduves friction .

4. Aids the digestion of food and absorption of nutrients in the body.

5. Regulates the body temperature