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INTRODUCTION TO
NUTRITION
BCH 282 (Lecture-1)
Dr. Saba Abdi
BCH 282 Biochemistry of Nutrition
(2+0) credit-hours
Topics
Energy of food, and its determination.
Carbohydrates
Proteins and fats of diets and their physiological
effects. Energy balance.
Water balance and sodium and potassium output.
Minerals and trace elements in diets and their
regulation to prevent epidemic diseases.
Vitamins and their importance.
.
Food poisoning.
Exam Mark
First CAT
: 20 Marks
Second CAT : 20 Marks
Final
: 60 Marks
•
•
•
Total = 100 marks
Dr.Saba Abdi
Books and References
1. Lippincott’s illustrated reviews: Biochemistry
2. Harper’s Biochemistry
3. Understanding normal and
clinical nutrition : Whitney , Cataldo , Rolfes
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What is nutrition?
The science of nutrition examines
the quantitative and qualitative
requirements of diet necessary to
maintain good health.
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. Diet: the food and beverages a person eats and
drinks.
Functional Food : Food that contains physiologically
active compounds that provide health benefits
beyond their nutrient contributions.
Energy : The capacity to do work . The energy in
food is chemical energy .The body converts this
chemical energy to mechanical, electrical and heat
energy.
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What is nutrient?
A nutrient is a chemical substance in food that helps
to maintain the body. Some provide energy. All
help build/repair cells and tissues, regulate bodily
processes such as breathing. Nutrients also helps to
reduce the risk of some diseases.
Nutrients can be grouped into 6 classes.
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The six classes of nutrients
Nutrients
Inorganic nutrients
Minerals
Organic nutrients
Water
Protein
Carbohydrates
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Lipids(fats)
Vitamins
Carbohydrates
Functions
• Provides our brains and body with glucose.
Characteristics
• 4 calories per gram.
Types of Carbohydrates
• Simple and complex carbohydrates
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Fats
Functions
• Carry and help with absorption of the fat-soluble
vitamins A, D, E and K.
• Protect organs from injury.
• Regulate body temperature.
• Play important role in growth and development.
Characteristics
• 9 calories per gram.
• Saturated , unsaturated fats and trans fats.
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Proteins-The main building blocks and
repair kit for body tissue
Functions
• Critical for growth, maintenance and repair of
• muscles, bones, blood, hair and fingernails.
• Key to synthesis of enzymes, hormones,
• antibodies and provide essential amino acids.
Characteristics
• 4 calories per gram.
• 20 amino acids total; 9 essential amino acids.
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Vitamins
Functions
• Help put proteins, fats, and carbohydrates to use.
• Essential to regulating growth, maintaining tissue,
• releasing energy from food.
• Involved in the manufacture of blood cells,hormones,
and other compounds.
Vitamins are classified by solubility:
• Fat-soluble: Vitamins A, D, E and K.
•Water-soluble: B vitamins (8 total) and vitamin C
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Minerals
Functions
• crucial components of enzyme systems
• regulate musculoskeletal functions
• responsible for nervous system transmission
• facilitate blood clotting
• ensure normal cardiac rhythm
Characteristics: 16 minerals
• Major: Sodium, potassium, chloride, calcium,
phosphorus, magnesium and sulfur.
.
• Trace: Iron, zinc, selenium, molybdenum,
iodine,
Water
Functions
• Essential for body temperature regulation.
• Transportation of nutrients and wastes in the body.
• All chemical reactions.
• Maintenance of blood volume.
• Yields no energy
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Macro. & Micronutrients
macronutrients :The intake of these energy-rich
molecules is larger than that of the other dietary
nutrients. Therefore, they are called the
macronutrients.
Micronutrients :Those nutrients needed in lesser
amounts, vitamins and minerals, are called the
micronutrients.
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.
Essential nutrient: Nutrients that are either not
made in body or are made in insufficient quantities,
but are needed for proper functioning of body. They
must be supplied to body from food.
Non nutrients: Compounds present in food but do
not fit within the six classes of nutrients. Such as
alcohols, phytochemicals, pigments, additives.
Energy yielding nutrients: carbohydrates, fats &
proteins.
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Variables which affect nutrient needs:
1. Age
2. Gender
3. Activity Level
4. Climate
5. Health
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Dietary Reference
Intakes: DRI consist of four
dietary reference
standards for the intake of
nutrients designated for
specific age groups,
physiologic states, and
gender
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Estimated Average Requirement
(EAR)
Estimated Average Requirement (EAR): The EAR is
the average daily nutrient intake level estimated to
meet the requirement of one half of the healthy
individuals in a particular life stage and gender
group. It is useful in estimating the actual
requirements in groups and individuals.
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Recommended Dietary Allowance
(RDA)
•
Recommended Dietary Allowance (RDA): The RDA is
the average daily dietary intake level that is
sufficient to meet the nutrient requirements of nearly
all (97–98%) the individuals in a life stage and
gender group. The RDA is not the minimal
requirement for healthy individuals; rather, it is
intentionally set to provide a margin of safety for
most individuals. The EAR serves as the foundation
for setting the RDA. If the standard deviation (SD)
of the EAR
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Adequate Intake (AI)
•
Adequate Intake (AI): The AI is set instead of an
RDA if sufficient scientific evidence is not available
to calculate an EAR or RDA. The AI is based on
estimates of nutrient intake by a group (or groups)
of apparently healthy people that are assumed to
be adequate. For example, the AI for young infants,
for whom human milk is the recommended sole
source of food for the first four to six months, is
based on the estimated daily mean nutrient intake
supplied by human milk for healthy, full-term infants
who are exclusively breast-fed.
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Tolerable Upper Intake Level (UL)
•
Tolerable Upper Intake Level (UL): The UL is the highest
average daily nutrient intake level that is likely to pose
no risk of adverse health effects to almost all
individuals in the general population. As intake
increases above the UL, the potential risk of adverse
effects may increase. The UL is not intended to be a
recommended level of intake. The UL are useful
because of the increased availability of fortified foods
and the increased use of dietary supplements. The UL
applies to chronic daily use. For some nutrients, there
may be insufficient data on which to develop a UL.
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The Food Guide
Pyramid
It is an outline of
what to eat each
day based on the
Dietary Guidelines
It's a general
guide that lets you
choose a healthful
diet.
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1.
2.
Aim for fitness (aim for healthy weight)
Be physically active each day
3.
Let the pyramid guide your choices
4. Choose a variety of grains daily, especially whole grains
5. Choose a variety of fruits and vegetables daily.
6. Keep food safe to eat.
7. Choose a diet that is low in saturated fat and cholesterol and
moderate in total fat
8. Choose beverages and foods to moderate your intake of sugars
9. Choose and prepare food with less salt
Dr.Saba Abdi