Food and Its Functions

What is food? The term food refers to anything which nourishes the body. It would obviously include solids, semi-solids and liquids which can be consumed and which help to sustain the body and keep it healthy.'We all know that food is a basic necessity Have you ever wondered why? Food is essential because it contains substances which perform important functions in our body. These essential substances contributed by our food arc called nutrients. If these nutrients are not present in our food in sufficient amounts, the result is ill health and in some cases, even death. Food also contains many substances which are non-nutrients  e.g. coloring and flavoring  substances in food. Food is. therefore, a complex .mixture of different nutrients and non-nutrients.

FUNCTIONS OF FOOD: You an now.familiar with the fact that food consists in part of various-nutrients. You may be surprised to know that there are over forty essential nutrients, which are supplied by the food we eat. These nutrients can k classified into five major categories (based on certain similar features): proteins,carbohydrates, fats, vitamins and minerals. Water is important as a nutrient as well as a food.  Each of the nutrient categories has a specific physiological role to play. Here the term "physiological role" refers to the role of food in maintaining certain specific body functions. Since food contains nutrients, it has physiological functions too, as you will learn in the subsequent paragraph. Food also has social and psychological functions in addition to physiological ones (Figure ).

Functions of food

Physiological Functions: The physiological functions performed by food are the energy-giving. body-building, protective  and regulatory functions. We need energy every moment cf our lives for performing various types of activities such as sitting, standing, walking and running and performing all our household and other tasks.You may not be aware of it but several activities take place within the body as well e.g. beating of the heart, contraction of  the intestines, expansion and contraction of the lungs. Activities performed within the body also require expenditure of energy The energy-giving function of food is basically performed by two nutrient categories--carbohydrates and fats. This is why these nutrients are also referred to as the "body fuels". The situation is similarity to the burning of coal or wood which are familiar fuels. When these fuels are burnt, energy is released in the form of heat and light. The fire we observe is, in fact, nothing bun the conversion of the energy locked up in the  fuel to heat energy and light energy. Similarly, carbohydrates and fats are burnt in the body, The energy that these substances  contain is  released to perform the. various  activities that we talked about  earlier.

Food is also needed for growth and repair. What is meant by these two terms:' As you know, our body is made up of millions of units called cells. When growth takes place, new cells are added to the existing ones. The existing ones also increase in size. On the other hand, cells do get worn out and die. These cells have to be replaced. This process is called repair. For both growth and repair, proteins are necessary.  We can understand the role of proteins in growth and development if we just think of the tremendous increase in height and weight that occurs from infancy  to adulthood. How does this take place? This is made possible by the-process of  growth.

The other major physiological functions performed by food are the protective and  regulatory functions. Let us talk about the meaning of the term 'protective' first. I Here protective refers to the role in preventing infection by ensuring proper r functioning of the body systems responsible for fighting infections. Even if a person does develop an infection or any other type of illness, food and the nutrients it contains facilitate rapid recovery. A person eating a poor diet would take much longer to recover. He would get ill more easily as well. 

The regulatory function mentioned earlier refers to the role of food in controlling body processes. As you are aware, several processes take place in the body such as the beating of the heart, maintenance of body temperature and contraction of muscles. Each of these processes is controlled. Our body temperature, for example, is maintained at 98.4"F or 37'C. Similarly, the rate at which the heart beats is also maintained. This is achieved by certain specific nutrients (among other substances) and is illustrative of their regulatory function. Vitamins, minerals, and proteins contribute substantially to both protective and regulatory functions. So does water.

You are also probably aware that several chemical reactions take place in the body. With the aid of these chemical reactions, simpler substances are used to build more complex ones. Similarly, complex substances are broken down into their simpler components. Figure below shows you how one or two types of simple units join to form complex substances and how complex substances break down into their simpler units.. The rate at which these reactions proceed is carefully controlled according to the need of the body. Vitamins, minerals and proteins play a major role in controlling these reactions i.e. they act as regulators.

lnterconversion of simple and complex substances

Social Functions : Food an.d eating has significant social meaning. Sharing food with any other person implies social acceptance. When you share a meal with anyone else, you are expressing your acceptance of and friendship and respect for that person. Earlier only persons enjoying equal status in society ate together. A person would never share a meal with someone inferior to him in social tern. Of course, we observe considerable change in this respect now particularly in cities and tom. In a restaurant, for example, any person can eat irrespective of his social background if he has the money to pay for the food.

Food is an integral part of festivity anywhere in the world. You must have surely noticed that joyous occasion & such as the birth of a child or a marriage are celebrated by having feasts and serving delicacies. Festivals such as Diwali, Dussehra, Pongal, Onam. Lohri, Holi, Christmas and Id are celebrated by having special and prescribed menus. In all these cases, food serves the function of bringing people together.

Food also has a specific significance and meaning in the religious context. Certain food items such.as fruits, sweets and coconuts are offered to the deity in temples. Often sweets are prepared at temples and gurdwaras and distributed to devotees as a benediction or prasad. Further, people of a given religious community share a common eating pattern. This is because religious texts and practices strongly recommend some foods while rejecting others. Food thus becomes an integral part of the social and religious life of people.

Physiological Functions : We all haw emotional needs such as the need for security, love and attention. Food is one way through which those needs are satisfied. When a mother prepares her child's favourite dish, the child recognizes the fact that she lovm him enough to remember his likes and dislikes. He appreciates the attention he is given. As you arc aware, when people share food it serves as a token of friendship and acceptance. A child quickly accepts foods eaten by his friends and by people he admires or wants to identify with. He may even accept food he first found distasteful  if he observes his friends enjoying it. Sharing the same food as others around him and those he considers important in his social sphere gives him a degree of  confidence in himself and reassures him that he will be accepted by others like him.

Food is also closely allied to our emotions. Food often serves as a reward. When a mother wishes to reward her child for doing well in a test, she may buy him a sweet or an ice cream. In this manner, that particular food item evokes pleasant feelings in the mind of the child. On the other hand, certain foods become associated with sickness such as khichri (a rice-dal porridge). This type of food is generally eaten when a person suffers from fever and may, therefore, not be associated with pleasant feelings.