Nutrition - Definition, Types, Examples

The process by which organisms take in and utilize food is called nutrition. The study of nutrition is called nutritional science or trophology. Essential Nutrients are elements in food that are essential for health and maintaining body functions. These essential nutrients are divided into macronutrients (carbohydrate, protein and fat), micronutrients (vitamin and mineral), and water. A balanced diet is one that includes all the nutrients the body needs in the proper amounts for growth and maintenance. Normally a balanced diet should provide about 2400 calories per day for a normal adult. Milk is an example for balanced diet. The headquarters of National Institute of Nutrition is located at Hyderabad.

Types of Essential Nutrients

1. Carbohydrate

It is one of the three main classes of nutrients essential to the body. The others are fats and proteins. Carbohydrates include all sugars and starches and also some other substances such as cellulose and glycogen. They are the main source of energy for animals and plants. They are used by the body as fuel. Foods high in carbohydrate content include bananas, bread, potatoes and rice. Carbohydrates consist of carbon, oxygen and hydrogen atoms arranged in 'building blocks' called Saccharides, Glycogen, or animal starch, is the chief form of stored carbohydrate in animals.

2. Protein

Protein is one of the three main classes of food that essential to the body. The others are carbohydrates and fats. Proteins exist in every cell and are essential to plant and animal life. Plants build proteins from materials in the air and the soil. Human beings and animals obtain proteins from the foods they eat. Foods that are high in protein content include cheese, eggs, fish, meat and milk. In 1838, a Dutch chemist Gerardus Johannes Mulder introduced the word 'protein'. In 1907 Emil Hermann Fischer, a German chemist built a protein molecule made up of 18 amino acid.

3. Fat

Fats are insoluble in water but soluble in organic solvents. Major sources of fats are butter, ghee, oils, ground nuts, almonds etc. One gram of fat yields 9.3 calories of energy. Fat is any of a group of chemical compounds found in both animals and plants. Carbon, hydrogen, and oxygen make up fats. They belong to one of the three major dietary groups that the body needs. The others are carbohydrates and proteins. An animal fat or plant that is liquid at room temperature is called an oil. Alcohols, chloroform, ether, and petrol can dissolve fats and oils, but water cannot dissolve them. Some fats are hard, while some other fats are soft. Fats in butter, lard and margarine are soft at room temperature.

4. Vitamin

The Englishman Sir Frederick Gowland Hopkins is credited with the discovery of idea of vitamin concept. He discovered in 1906 that food contains important elements called vitamins other than carbohydrates, minerals, fats, proteins, and water. Hopkins shared the 1929 Nobel Prize in medicine and physiology for his discovery of growth stimulating vitamins. Polish born Casimir Funk (US) made great advances in 1912 when he hypothesized that certain diseases such as beriberi, scurvy, pellagra and rickets are caused by deficiencies of nutrients he called 'vitamins'.

5. Mineral

Mineral is a homogenenous inorganic material needed for body. These control the metabolism of body. The important minerals in our body are sodium, potassium, calcium, phosphorous, iron, iodine, magnesium, zinc, copper and cobalt.

6. Water

Human get water by drinking. Water is the important component of our body. 65 to 75 percent weight of the body is water. Although humans have used water since the dawn of civilization, its exact chemical composition was not known until 1784, when the English chemist Henry Cavendish discovered that it consisted of hydrogen and oxygen. Later he proved the exact ratio of the two gases.