Wednesday, 25 July 2012

10.1.1/ 10.1.2 Main Constituents of Food

Definition of Nutrition:

The science of nutrition is the study of food and the process of growth, maintenance and repair dependent on digestion (catabolism and anabolism).

General about Food

“Food is our fuel for metabolism, metabolism is all the chemical processes that go on necessary to maintain life, also to produce energy” 

E.C. Syncowki

Food is any solid or liquid which provides:

  • materials for growth, maintenance and repair,

  • materials for heat and energy production,

  • substance to regulate body processes,

Different classes of nutrients:

Nutrients are chemical substances found in food during digestion, which are necessary to regulate the body processes and to suply heat and energy. 

  • there are six main nutrients
  • there are 3 energy giving nutrients

Nutrients can be sub-divided into Macronutrients and Micronutrients.

  • Macronutrients
"an essential nutrient required in relatively large amounts, such as carbohydrates, fats, proteins, or water; sometimes certain minerals are included, such as calcium, chloride, or sodium."
Dorland's Medical Dictionary for Health Consumers. © 2007 by Saunders, an imprint of Elsevier, Inc.


Primary source of energy for body functions and muscular exertion. 

Composed of carbon, hydrogen and oxygen,


Which are needed for growth and formation of new tissue
and  for tissue repair.

Composed of hydrogen, carbon, oxygen and nitrogen.


Second energy source. 
Fat  acts as an insulator and this maintains body temperature
protects internal organs from shock and injury.

Composed of hydrogen, carbon, oxygen.

Check out this video to learn more about Macronutrients:

What Is A Macronutrient - Intralean

Uploaded by Fitnfunn on 6 Nov 2009

  • Micronutrients
any dietary element essential only in minute amounts for the normal physiologic processes of the body, including vitamins and minerals or chemical elements such as zinc or iodine.
Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.


Chemical compounds which are essential for health. They are not eaten as such in the diet but are found widely dispersed in the food which is eaten. They are divided into two groups: fat soluble vitamins and water soluble vitamins.


Necessary within a body for all body processes. They are required in varying quantities, usually small.

  • Water

Water can be considered the most important dietary constituent. Liquid compound of hydrogen and oxygen. Neccesary for all cell functions. Water provide body fluid and help regulate body temperature.

Check out this video to learn more about Macronutrients and Micronutrients and the main constituents of food:

2-1 UC Berkeley Nutrition 2007: Designing a Diet

Uploaded by LatestNutrition on 8 Jan 2010

To read more about functions of food clink the link below:


  1. Excellent information, clearly explained and easy to understand

  2. Excellent information, clearly explained and easy to understand

  3. Excellent information, clearly explained and easy to understand