1. CHS 214
Introduction to the Science of
Nutrition and
Related Definitions
Lecture 1

2. Objectives
 Introduction
 Definitions
 Energy from food
 Functions of food nutrients
 Composition of human body
 Nutrition assessment of individual
 Sign of good nutrition
 The relationship of nutrition with other
sciences
 Nutrient intake limits

3. Introduction
 Most of the organized studies of nutrition have been
confined to the 20th century.
 Although there was evidence of long-standing curiosity
about nutrition.
 Hippocrates, the father of medicine(400 BC)
considered food as one universal nutrient.
 Antonie Lauret Lavoisier(18th century, a French
chemist) is known as father of nutrition.
 In Islam there are many verses of the Quran and
Hadeeths in food and nutrition.
 Some of these fact has just been proved by the
modern science and some not.

4.  Nutrition has played a significant role in our
life, even from before our birth.
 Many people are concerned only with food
that relives their hunger or satisfies their
appetite .
 But in many times, these foods don't supply
their bodies with all the component of good
nutrition.

5. Definitions
Food Diet Nutrients
Nutrition
Nutrition
requirement
Nitrogen balance
Nutrition science Adequate diet Junk food
Nutritional
status
Nutritional care Calories
Empty calories Malnutrition Metabolism
Nutritive value Dietetics Nutritional genomics

6.  Food:
Foods are products derived from plants or
animals .
that can be taken into the body to yield
energy and nutrients for maintenance of life
,for growth and repair tissues.
Food is that nourishes the body.
Food is a prerequisite of nutrition.

7.  Diet
Diet is the foods and beverages a person eats
and drinks.

8. Food
Nutrients
1-Macronutrients
2-Micronutrients
Other
compounds
-fibers
-phytochemicals
-pigments
-additives
-alcohols
-and others
Food composition

9. Nutrients:
Chemical substances obtained from foods used in the
body to provide energy, structure materials, regulating
agents to support growth, maintenance, repair of body's
tissues and may also reduce the risks of some
diseases.

10. Nutrients divided into two categories:
 Macronutrients
 Are the nutrients which the body needed in large
amount such as carbohydrate, protein and fats.
 Carbohydrates, protein and fats are the main source of
energy for human body.
 Are the energy yielding nutrients.
 Micronutrients
Are nutrients needed in lesser amounts such as:
Vitamins & minerals.

11. Chemical composition of the nutrients
Nutrients
Inorganic
(water &Mineral)
Organic
(CHO, lipids , protein and
vitamins)
Organic nutrients: substance that contain carbon atom.
Inorganic: substances that do not contain carbon atoms.

12. Essential nutrients:
Are nutrients a person must obtain from food
because the body cannot make them for itself
insufficient quantity to meet physiological needs.
Also called indispensable nutrients.

13.  Nutrition:
• Nutrition is the science of foods, nutrients
and other substances they contain their
actions within the body (including ingestion,
digestion, absorption, transport, metabolism
and excretion).
• A broader definition includes the social,
economic, cultural, and psychological
implications of food and eating.

14.  Nutritional requirements
The amounts of nutrient which are needed for
covering the human needs to be healthy depend on
sex, age and few other factors.

15.  Nutritional status
An individual condition of health in relation to
digestion and absorption of nutrients.
 Nutritional care:
Application of the science of nutrition in
nourishing the body regardless of health
problems or potential problems.

16. Adequate diet: is a diet providing
all the needed nutrients in the right total
amounts.
Junk food:
Refers to foods that are harmful.

17.  Calories
• The energy released from carbohydrates, proteins
and fats can be measured in calories.
• A calorie is the amount of heat necessary to raise
temperature of 1 gm of water by 1 C.
• 1000-calorie metric units are known as kilocalories
(kcal).
Empty-kcalorie foods
a popular term used to denote foods contribute
energy (from sugars, fat or both)
but lack in protein, vitamins and minerals
Example:(potato chips and candies).

18.  Dietetics
the health profession responsible for the application
of nutrition science to promote human health and
treat disease
 Metabolism
The sum of all chemical reactions that take place in
the body which it maintains itself produces energy
for its functioning.

19.  Nutrition science
Nutrition science:
1-The study of nutrients and other substances in foods
and the body's handling of them.
2-Its foundation depends on several other sciences
including biology, biochemistry, and physiology.
3- Comprises the body of knowledge governing the food
requirement growth, activity, reproduction and lactation.

20.  Nutritional genomics:
the science of how nutrients affect the
activities of genes and how genes affect the
interactions between diet and disease.

21. Malnutrition:
Malnutrition has two types:
 Undernutrition: deficient energy or nutrients.
•Symptoms of under nutrition (extremely thin, losing
muscle tissues, prone to infection and disease, skin
rashes, hair loss, bleeding gum and night blindness).
 Overnutrition: excess energy or nutrient.
•Symptoms of overnutrition (heart disease, diabetes,
yellow skin, rapid heart rate and low blood pressure).

22.  Nitrogen balance
 The proteins in the body undergo constant
turnover (degraded to amino acids and
resynthesized).
 Nitrogen balance is the difference between
the amount of nitrogen taken into the body
each day and the amount of nitrogen in
compounds lost.

23.  if: 1- More nitrogen is ingested than excreted, a
person is said to be in positive nitrogen balance
(growing individual such as children and pregnant).
 2- Less nitrogen is ingested than is excreted
(negative nitrogen balance, person eating either
too little protein or protein is deficient in one or more
of the essential amino acids, new protein cannot be
synthesized and the unused amino acids will be
degraded, body function will be impaired by the net
loss of critical proteins.
 3- In contrast, healthy adults are in nitrogen
balance and the amount of nitrogen consumed in
the diet equals its loss in urine.

24.  Nutritive value
The amounts of nutrient which the food consist of,
determined by using:
 Food analysis.
 Food analysis tables.

25. Energy from food
 The amount of energy a food provide depends on
how much CHO, fat, and protein contains.
 When completely broken down in the body,
1 gm CHO 4 kcal of energy
1 gm protein 4 kcal of energy
1 gm of fat  9 kcal of energy
therefore fat has the greater energy density than
either CHO or protein.
 Alcohol is not considered a nutrient because it
interferes with health but it yields energy
1 gm of alcohol 7 kcal of energy

26. Functions of food nutrients
1-Provide energy sources
2-Build tissues
3-Regulate metabolic process

27. 1-Provide energy sources
 The major carbohydrates in the human diet are
starch, sucrose, fructose and glucose.
 Dietary carbohydrate (starches and sugars)
provided the body's primary source of fuel for
energy.
 Oxidation of carbohydrates to CO2 and H2O in
the body produces approximately 4 kcal/g.
 They also maintain the back-up store of quick
energy as glycogen (animal starch).

28.  Fats are lipids composed of triacylglycerols.
 A triacylglycerol molecule contains three fatty acids
esterified to one glycerol molecule.
 Dietary fats, from both animal and plant
sources, provided the body's secondary or storage form
of energy.
 It is a more concentrated, yielding 9 kcal for
each gram consumed.
 In a well-balanced diet, protein provided about 15 % of
the total kcalories.
 Each gram of protein can yield 4 kcal.

29. How to calculate the energy available from 1
slice of bread with 1slice of bread with 1
tablespoon of peanut butter on it contains
16 grams carbohydrate, 7 grams protein
and 9 grams fat?

30. 2-Build tissues
• Proteins are composed of amino acids that are joined to
form linear chains.
• The digestive process breaks down proteins to their
constituent to amino acids, which enter the blood.
• The primary function of protein is tissue building and
repairing body tissues.
• Dietary protein provides amino acids, amino acids are the
building unit necessary for construction and repairing body
tissues.
• Muscle protein is essential for body movement.
• Other proteins serve as enzymes.
• Other nutrients such as minerals and vitamins used in tissue
building and maintaining tissue.

31. • Minerals are also found in the fluids of the body and
influence their properties.
• There are 13 different vitamins, one vitamin enables the
eyes to see in dim light,
protect the lungs from air pollution
make the sex hormones,
stop the bleeding,
helps repair the skin,
replace old blood cells and lining of the digestive tract.

32. 3-Regulate metabolic process
• Many vitamins and minerals function as coenzymes
factors in cell metabolism.
• Other nutrients (water and fibers),
water provides the environment in which nearly
all the body's activities.
Also, in many metabolic reactions and supplies the
medium for transporting vital materials to cells and waste
products away from them.
• Dietary fibers help regulate the passage of food
material through the gastrointestinal tract and influences
absorption of various nutrients.

33. Composition of human body
61%
17%
14%
6% 2%
water (61%)
Protein (17%)
Fats(13.8)
Minerals(6.1%)
Carbohydrates(1.5)

34. Nutrition assessment of individual
Evaluation of person's nutrition
1- Historical information (socioeconomic status, drug use,
diet and person's family history).
2-A=Anthropometric data (height and weight).
3- B= biochemical data (Laboratory tests).
4-C=clinical assessment(Physical examinations)
5-D=Dietary assessment

35. Sign of good nutrition
1. Well-developed body.
2. Ideal weight.
3. Good muscle development.
4. The skin is smooth and clear
5. The hair glossy and the eyes clear and bright.
6. Appetite, digestion and elimination are normal.
7. Have good resistance to infection.

36. The relationship of nutrition with
other sciences
Nutrition
food
science
physiology
biochemistry
biology
microbiology
Medicine

37. There are three main areas of overlapping
between nutrition and medicine:
1-dietary control of disease.
2-the relationship between diet as a possible
causative factor in disease ex: cancer, heart
diseases etc.
3-the toxicology of natural and processed foods.

38. Nutrient intake limits
Safety
RDA
Danger
Danger of toxicity
marginal
Safety
RDA
Safety
marginal
Danger of
deficiency
Naive View
Accurate View

39. Thank you for
listening 