A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment.
Organic nutrients include carbohydrates, fats, proteins (or their building blocks, amino acids), and vitamins. Inorganic chemical compounds such as dietary minerals, water, and oxygen may also be considered nutrients.A nutrient is essential to an organism if it cannot be synthesized by the organism in sufficient quantities and must be obtained from an external source.
Substances that provide energy - Carbohydrates, Fats, Proteins.
Substances that support metabolism - Vitamins, Water, Dietary Minerals.
Vitamins:
Vitamins are organic compounds essential for life, health and growth. They are not eaten as in the diet, but are widely dispersed in food.
Two Kinds of Vitamins:
- Fat soluble vitamins - Vitamin A, Vitamin D(Calciferol), Vitamin E(Tocopherol) and Vitamin K
- Water soluble vitamins - Vitamin B1(Thiamine), Vitamin B2 (Riboflavin), Nicotinamide, Vitamin B6(Pyridoxine), Panthothenic acid, Biotin, Folic acid (Pteroyglutamic acid), Vitamin B12 and Vitamin C.
Why Vitamins are Valuable?
Vitamins are chemical substances present naturally in most foods and in synthetic form, like in vitamin pills. Both forms are equally nutritious since the vitamins in each case are chemically identical. The body needs only tiny quantities of them- ranging from about 30mg(30 thousandths of a gram) a day of Vitamin C. For instance, down to 1 micro-gram (one millionth of a gram)of Vitamin B12. They play no direct part in producing body tissues or energy, but they are essential for the body to function efficiently, just as oil is essential for running of a car.
Vitamins deficiency can lead to illness and in extreme cases, death. The killer diseases Scurvy and beri-beri are caused by deficiencies of the vitamins C and B1 respectively. Deficiency of Vitamin A can cause Night Blindness, and Deficiency of Vitamin D leads to rickets ( a childhood disease of bones).
Anyone, who eats a variety of foods, however, is unlikely to run into problems.
What are Carbohydrates?
They consist of Carbon, Hydrogen and Oxygen. They are found in sugar, jams cereals, bread, potatoes, fruit, vegetables and milk.
Functions of Carbohydrates:
- In the body they are utilized to provide energy and heat.
- They help to maintain the normal blood glucose level.
Three main groups of carbohydrates:
- Mono-saccharides,
- Di-saccharides and
- Polysaccharides.
What are Proteins?
Proteins are complex compounds containing carbon, oxygen, nitrogen, sulphur and phosphorous. They are obtained mainly from meats, eggs, milk, cheese, fish, cereals and certain vegetables.
Essentials of Proteins:- To repair body tissues
- Maintenance of the osmotic equilibrium between blood and tissue fluids
- Providing energy and heat when there is an insufficient supply if Carbohydrates.
Fats(Lipids)
Fat is important in the diet not only for its high energy but also it contains the fat soluble Vitamins A, D, E and K and certain essential fatty acids.
Necessity of Mineral Salts:
Mineral Salts are necessary in diet for all body processes. Only small amount of it is needed.
Use of Calcium:
Calcium is the chief constituent of teeth and bones. it is absorbed in the small intestine with the help of Vitamin D. It plays an important part in the coagulation of blood and in contraction of muscles.
Use of Phosphate:Phosphate combines with calcium in the formation of bone and teeth and it helps to maintain the normal composition of body fluids.
Importance of Sodium:
Sodium present mainly in tissue fluids and therefore play an important role in cell activity and in the fluid balance of the body.
Use of Potassium:
Potassium is an essential constituent of all cells. It is also necessary for the normal activity of cardiac, skeletal and smooth muscles.
Importance of Iron in the body:
Iron is necessary for the formation of cytochromes that is involved in tissue oxidation. It is very essential for the formation of Haemoglobin.
Importance of Iodine:
Iodine is essential for the formation of the Thyroid hormones, thyroxine and tri iodothyronine.
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