Unit 1 - Basic Concepts of Nutrition

Introduction

• Food is a basic need for all living beings.
• Food gives us energy to carry out our day-to-day activities and keeps all the system in our body functioning well. 
• Food supplies the nourishing substances needed by our body to build and repair tissues and to regulate various function.

DEFINITIONS

Food: Food can be defined as any substance which nourishes the body and is fit to eat. It may be solid or liquid. Food provides the body with materials for providing energy, growth and maintenance, and regulating various processes in the body. These materials of which food is made up of are termed as nutrients.

Nutrients: Nutrients are the chemical substances present in food, which the body needs to carry out its functions. There are six major groups of nutrients, namely, proteins, carbohydrates, fats, vitamins, minerals, and water.

Nutrition: Nutrition is the science of nourishing the body. It includes much more than just consuming a balanced diet. Nutrition is a study of various nutrients, their characteristics, functions, requirement and sources. The effect of deficiency, excessive intake, digestion, absorption and utilization in the body as well as the interrelationships that occur among some nutrients is an important part of nutrition.

Health: Health is the ability of a biological system to acquire, convert, allocate, distribute, and utilize energy with maximum efficiency.

RELATION OF FOOD AND HEALTH

Malnutrition: Malnutrition is an impairment of health resulting from a deficiency, excess, or imbalance of nutrients in the diet. It includes both under nutrition or deficiency and over nutrition or excessive consumption.

Undernutrition: It refers to a deficiency of calories and/or one or more nutrients in the diet. An undernourished person is underweight.

Over nutrition: It refers to an excess of calories and/or one or more nutrients in the diet. An excessive intake of calories results in overweight which can lead to obesity. An excessive intake of fat soluble vitamins can cause hypervitaminosis or vitamin toxicity.

Diet: A diet means the kinds and amounts of food and beverage consumed every day. A diet may be normal diet or it may be a modified diet which is used in the treatment of specific disease or condition.

NUTRITIONAL STATUS

The nutritional status of an individual is defined as the condition of health as influenced by the utilization of nutrients in the body. The nutritional status of an individual or a community can be assessed by surveying the kind and amount of food being consumed, signs of ill health or deficiency symptoms if present, height, weight, and other measurements as well as level of nutrients in the blood and excreted in the urine.

CLASSIFICATION OF NUTRIENTS

Nutrients are the essential constituents of food that are required by the body in suitable amounts. There are approximately fifty nutrients which are placed in six categories, namely, proteins, carbohydrates, fats, vitamins, minerals, and water.
The requirement for macronutrients is in grams, while the requirement for micronutrients is in milligrams and micrograms.

CLASSIFICATION OF NUTRIENTS

FOOD AND ITS FUNCTIONS

Physiological functions:

Each nutrient in food has specific functions to perform in the body. The physiological functions performed by food are as follows:

1. Providing energy: The body needs energy to carry out voluntary and involuntary work. Involuntary work includes all process which is not under the control of our will such as digestion, respiration, and circulation and goes on continuously irrespective of whether we are asleep or awake. Voluntary activities or activities which we wish to do such as walking, playing game and working require energy, and the amount of energy required will depend on the nature of activity. The energy needed for these activities in supplied by oxidation of the foods we eat mainly carbohydrates and fats.


2. Body building or growth: It is one of the most important functions of food. An infant grows into a healthy adult by consuming the right kinds and amount of food year after year. Our body is made up of millions of cells and when growth takes place, new cells are added to the existing cells and cells increase in size.

3.Maintenance or repair: In the adult body, worn out cells are continuously being replaced by new ones. The daily wear and tear of cells needs to be maintained. Proteins, minerals, and water are the main nutrients required for growth as well as maintenance of all cells and tissues in the body.

4. Regulation of body processes: Food also regulates numerous activities in the body such as the beating of the heart, maintenance of body temperature, clotting of blood, and excretion of wastes. Each of these processes is controlled and carried out by specific nutrients for example vitamin K and calcium is necessary for clotting of blood.


5. Protective function: Nutrients keep body cells in a healthy condition to ward off infection, they help in building up the body’s resistance to disease and help the body recover rapidly from any infection. These functions are performed by vitamins and proteins.

Psychological function

We all have emotional needs such as need for love, attention, and security. Food can play an important role in fulfilling these needs. Mother can express her love for her child by preparing the child’s favourite meal. Food can be given as a reward for good behavior or deprived as a punishment for bad behavior. People feel comfortable and secure when they are served food they have been used to consuming. Many people eat to relieve anxiety and frustration, while some may eat less or refuse food when they are depressed and lonely. Food is therefore strongly associated with one’s emotions and feelings.

Social function

Food carries a lot of social significance. Warmth and friendship are expressed through sharing one’s food or inviting people to dine. Preparing special foods or ones favourite food is a way of showing respect or affection.

Food is a significant part of celebrations for occasions such as birthdays, weddings, and other joyous occasions. Festivals such as Diwali, Dussehra, Christmas and Id have special menus prescribed for the occasions.

Food also has religious significance. Some foods can be offered to god, while other are avoided on certain days for religious reasons. The type of food prepared and served is a status symbol. Even today, in some communities, adult males are given more and better quality food than females because of their higher social status.