Nutrition is the science of food and its interaction with an organization to promote and maintain health. Thus nutrition is a combination of processes by which all parts of the body receive and utilize the materials necessary for the performance of they functions and for the growth and renewal of all the components. Optimum nutrition means that a person is receiving and utilizing essential nutrients in proper proportions as required by the body while also providing a ‘reserve’. Good nutritional status refers to the intake of a well-balanced diet, which supplies all the essential nutrients to meet the body’s requirements. Such a person may be said to be receiving optimum nutrition. Poor nutritional status refers to an inadequate or even excessive intake or poor utilization of the nutrients to met the body’s requirements. Overeating can also result in poor nutritional status of a person. Malnutrition refers to the physical effects on the human body of a dietary intake inadequate in quantity and / or quality. Under nutrition refers to low food intake. The critical unit of food energy intake may be defined as 1.2 BMR. The BMR (Basal Metabolic Rate) is the minimum energy expenditure necessary for body maintenance at rest with no physical activity.

Shiny hair, smooth skin, eyes and alert expression and firm flesh on well-developed structure reflect good nutritional states of a person. A person ought to be of correct weight in relation to his height. His physical and mental responses should be normal. Good nutritional status of a person is also reflected by his stamina and resistance to diseases. Good nutrition also helps a person have regular sleep and elimination habits. It may increase a person’s life span. In short, a person with a good nutritional status can enjoy life fully.

These are seen in a person who has an apathetic attitude in general towards life. He has a poor physique, very little stamina, dull lifeless hair, dull eyes, slumped posture, fatigue and depression. He may be grossly overweight or underweight. The three important aspects namely those of diet, sleep and elimination habits are irregular. Clinical symptoms of nutritional deficiency may be evident in some. In most cases sub-clinical nutritional deficiencies may be present, but may not exhibit any symptoms.

Proteins are vital to any living organism. Proteins are the important constituent of tissues and cells of the body. They form the important component of muscle and other tissues and vital body fluids like blood. The proteins in the form of enzymes and hormones are concerned with a wide range metabolic process in the body. Proteins supply the body building material and make good the losses that occur due to wear an tear. Proteins, as antibodies, help the body to defend against infections. Thus, proteins are vital to the living process and carry out a wide range of functions essential for the sustenance of life. Thus, proteins are one of the most important nutrients required by the body and should be supplied in adequate amounts in the diet. The protein needed by the body has to be supplied through the diet we consume. The dietary proteins are broken down into amino acids and absorbed replacement of protein depleted, etc. The amino acids not used for the above is used are broken down to provide energy. Proteins are required for maintenance (replacing the wear and rear in tissue) in adults, for growth in infants and children, for fetal development in pregnancy and milk output during lactation.

Present in small amounts in many foods. They are required for carrying out many vital functions of the body and many of them are involved in utilization of the major nutrients like proteins, fat and carbohydrates. Although they are needed in small amounts they are essential for health and well-being of the body.

A large number of minerals and trace metals are present in the body. Some of these form part of body structural component and some others act as catalytic agents in many body reactions. Bones and skeleton are made up mainly of calcium, magnesium and phosphorus, and iron is a component of blood. Minerals like zinc, molybdenum, copper, manganese and magnesium are either a structural part or activate a large number of enzyme systems. Iodine is a part of hormone, thyroxin. Sodium, potassium is important elements present in fluids within and outside the cells and along with ions like chloride, bicarbonate and carbonate keep water and acid base balance. In the case of growing infants and children, intakes of additional amounts of several minerals are essential to ensure adequate growth of tissues.