Food is one of the basic requirements for the continuation of human life and growth since the beginning of the twentieth century until now. By the continuous scientific researches, researchers have been able to develop the concept of nutrition to become a field of science.

Nutritional Science studies:

– Kinds and quantities of essential nutrients that we eat and their functions in the body.

– On one hand it studies, physical and chemical properties of the basic components of food.

On the one hand, it studies what may affect the quality of this food, starting with production and during manufacturing operations to consumption.

– Researching and planning suitable diets for differences in gender, age, nature of work and health condition, on both the individual level and the group level.

Nutrition plays an important role in different areas of life and affects life in different ways. We mention for example:

– Proper and adequate nutrition for working people is of great importance, as providing workers with the appropriate food quantities makes them able to produce well while a lack of food may make them more vulnerable to disease and a feeling of weakness and fatigue and thus the inability or lack of ability to work, and this in turn is reflected in the productivity of work, i.e. Community productivity and development.

– Studies show that malnutrition during the period of rapid brain development, that is, until the age of 3 years, affects the proper development of the brain and intellectual ability compared to children with adequate nutrition.

-It is well known that, the adult human body contains an average of 95% water, 81% protein, 81% fat, 3.3% mineral salts and 7.0% carbohydrate in addition to vitamins, nuclear acids, hormones and enzymes. These compounds are present in every cell of the body, and each compound has its own characteristics and functions in building the body and it works through a set of reactions and chemical variables that occur in the cells.

These chemical reactions are what we call “metabolism” and can be summarized by the processes of demolishing and building nutrients in order to supply the body with energy on one hand, and building the body on the other hand.

In other words, the term nutrition does not only mean eating food with the goal of filling the stomach, but also providing the body with the nutrients necessary for its growth and work.

Before discussing the topic of nutrition, it is necessary to explain some concepts related to the topic:

.1 Nutrition

A group of processes through which an organism obtains the materials it needs from its surrounding environment and exploits it for its effectiveness and needs. These processes include: digestion, absorption, metabolism and excretion.

.1.1 Digestion

A process in which large molecules are broken down into small molecules that the body can benefit from, including the movement of food within the digestive tract.

Mechanisms of digestion:

  • Chemical: as stomach acid HCl.
  • Enzymatic: Like digestive juices in the intestine.
  • Mechanical: like grinding food in the mouth and stomach movement.

2.1 . Absorption

It is the process by which nutrients are captured after being digested by lymphatic or blood vessels.

Then these nutrients are carried to all cells of the body to be used properly.

There are two absorption mechanisms:

  • Effective diffusion: the concentration gradient is reversed and requires carriers and energy.
  • Passive diffusion: It is carried out with two mechanisms either with a concentration gradient without the need for carriers or energy, or with a gradient focus without the need for energy, but with carriers and channels.

1.1 . Metabolism

It is the process by which nutrients are introduced into cells for use in tissue building, energy acquisition, and restoration of old tissues.

There are two types of metabolism:

  • Anabolism: It needs energy, such as obtaining glycogen from glucose.
  • Catabolism: It is an energy product, such as the release of glucose from the destruction of glycogen.


.2 Nutrient:

It is a substance that is digested and absorbed and then used for some function in the body. The nutrient may be essential or non-essential.

Essential Nutrient: It is a substance that the body cannot synthesize and must be obtained from food intake, such as some amino acids and fatty acids.

The nutrients are divided into two types:

  • Macro Nutrients: Protein, Fat & Sugars.
  • Micro Nutrients: Vitamins and Minerals.

Note: Water is classified as a nutrient as well.

.1 Food

It is substances that must provide the body with at least one nutrient (after this food has been ingested, digested and absorbed)