Nutrition:

 

INTRODUCTION TO NUTRITION

Definitions

      Nutrition: - is the sum total of the process by which living things receive and utilize the necessary materials for survival, growth and maintenance of worn out tissues.                          

Definitions

      Nutrition: - is the sum total of the process by which living things receive and utilize the necessary materials for survival, growth and maintenance of worn out tissues.                          

Definitions

      Nutrition: - is the sum total of the process by which living things receive and utilize the necessary materials for survival, growth and maintenance of worn out tissues.                          

Definitions

      Nutrition: - is the sum total of the process by which living things receive and utilize the necessary materials for survival, growth and maintenance of worn out tissues.                          

• Those that supply energy are the carbohydrates and fats. 

• Those responsible for growth and repair of tissues cells are proteins.

• Those, which regulate chemical process in the body, are the vitamins and minerals. 

• Water is present in most foods and is an indispensable component of our bodies. It is the means of transportation for most nutrients and is needed for all cellular activities.

• Roughage: - is defined as food fibers which enable the body to get rid of waste products, which would otherwise become poisonous to the body. It prevents gastrointestinal disorders (gastritis, appendicitis, gallbladder stone and constipation) and metabolic disorders (diabetes mellitus, hypertension, ischemic heart disease and colon cancer).

Malnutrition: - is the condition that results from an imbalance between dietary intake and requirements. It includes under nutrition, which results from less food intake and hard physical work and over nutrition results from excess food intake and less physical activities

Functions of food

Human beings need food to provide energy for the essential physiological functions like:-

 Respiration

 Circulation

 Digestion

 ƒ Metabolism

 Maintaining body temperature.

 Growth and repair body Tissues

 An adequate supply of nutrients is needed to maintain all the functions of the body and daily activities at maximum efficiency, thus ensuring healthy living.

 Health and nutrition are closely linked and to ensure proper development and life quality they must be adequate from early childhood 

 Most vulnerable groups are infants, young children, pregnant women and lactating mothers

The energy requirements of individuals

Good nutrition must meet the needs of varying ages and activities and always with individual differences. Therefore, the planning of food to meet especial needs begins with:

  Pregnant women

  Nursing mothers

  Infants

  Adolescents and

  Adults

  The energy requirements of individuals depend on:

  Physical activities

  Body size and composition

  Age may affect requirements in two main ways

  During childhood, the infant needs more energy b/c growing

  During old age, the energy need is less because aged people are engaged with activities that requires less energy. 

 Climate: Both very cold and very hot climate restrict outdoor activities.

 In general feeding is dependent on the controlling centers, appetite and satiety in the brain. 

 There are a variety of stimuli, nervous, chemical and thermal, which may affect the centers and so alter  feeding behavior

The energy derived from food is measured by unit called calorie.

Calories

 A calorie is a measure of energy—technically, the amount of energy needed to raise the temperature of one gram of water one degree Celsius.

Each gram of carbohydrate or protein can supply 4 kilocalories while, for each gram of fat consumed, the amount of energy supplied is more than double, 9 kilocalories

Daily calorie requirements of individuals

 Infants 1 - 3 years need 1,000 cal/day

 Children 5 years need 1,500 cal/day

 Children 5 – 8 years need 1,800 cal/day

 Children 10 – 12 years need 2,000 cal/day

For adolescents and adults calorie requirements depend on the degree of physical activities

CLASSIFICATION BY PREDOMINANT FUNCTION

• Body building foods:

Ex:-meat, milk, poultry, fish, eggs, pulses etc

• Energy giving foods:

Ex:-cereals, sugars, fats, oils etc.

• Protective foods:

Ex:-vegetables, fruits, milk, etc

• Classification by origin:

    - Foods of animal origin

- Foods of vegetable origin

• Classification by chemical composition:

    -   Proteins

– Fats

– Carbohydrates

– Vitamins

– Minerals

Category of nutrients in food supply

Organic and inorganic complexes contained in food are called nutrients. They are broadly divided in to

 Most carbohydrates (“hydrated carbon”) contain atoms from one water molecule (H2O) for each atom of carbon 

 Monosaccharides are basic dietary carbohydrate and has six carbons (e.g. glucose, fructose, and galactose) 

 Glucose is the sugar in blood. Fructose is twice as sweet as

glucose and found in fruits. 

 Galactose is less sweet than glucose and present in milk.

 Disaccharides form when two monosaccharides join together.

 Polysaccharids:-are made up of more than two monosaccharides

 

 Polysaccharides, also known as complex carbohydrates.

 contain hundreds to thousands of individual sugar units

 For the most part, glucose is the only monosaccharide present. 

The different polysaccharides are distinguished by the way in which the glucose units are joined together, their arrangement, and their number 

Starch is the storage form of glucose found in plants; it occurs abundantly in seeds, some fruits, tubers, and taproots. 

 The presence of starch in foods can be traced directly to its plant origin; the starch in white bread or pasta was originally stored in the grain of a wheat plant. 

Starch is the storage form of glucose found in plants; it occurs abundantly in seeds, some fruits, tubers, and taproots. 

 The presence of starch in foods can be traced directly to its plant origin; the starch in white bread or pasta was originally stored in the grain of a wheat plant. 

• Glycogen is the body’s storage form of glucose, found in the liver and skeletal muscles. 

• When the levels of glucose in the blood are higher than the demands of the cells,the excess is used for the synthesis of glycogen in liver and muscle cells. 

• Only a limited amount of glycogen can be stored as a reserve—no more than a day’s worth of energy needs.

• Glycogen is the body’s storage form of glucose, found in the liver and skeletal muscles. 

• When the levels of glucose in the blood are higher than the demands of the cells,the excess is used for the synthesis of glycogen in liver and muscle cells. 

• Only a limited amount of glycogen can be stored as a reserve—no more than a day’s worth of energy needs.