Download Essential nutrients

ThiQar college of Medicine
Family & Community medicine dept.
Nutrition Lecture 2
Third stage
by:Dr. Muslim N. Saeed
November 24th,2016
Nutrients (cont.)
organic : A substance or nutrient that contains the
element carbon.
inorganic : A substance or nutrient that does not
contain carbon.
*the term organic is commonly used to describe
foods that are grown with little or no use of
chemicals.
*Carbohydrates, lipids, proteins, and vitamins are
organic, because they contain carbon. Minerals
and water are inorganic.
Elements in the Six Classes of
Nutrients
Essential nutrients: nutrients a person must
obtain from food because the body cannot
make them for itself in sufficient quantity to
meet physiological needs; also called
indispensable nutrients. About 40 nutrients are
currently known to be essential for human
beings.
calories: units by which energy is measured.
Food energy is measured in kilocalories (1000
calories equal 1 kilocalorie),abbreviated kcalories
or kcal.
One kcalorie is the amount of heat necessary to
raise the temperature of 1 kilogram (kg) of water
1°C.
*for the sake of simplicity, nutrition labels and
publications intended for consumers use the term
calorie with a letter “c” to represent the unit of
kilocalories.
Kcalorie Values
of Energy Nutrients
Nutrients
Energy(kcal/g)
Carbohydrate
4
Fat
9
Protein
4
NOTE: Alcohol contributes 7 kcalories per gram that
can be used for energy, but it is not considered a
nutrient because it interferes with the body’s
growth, maintenance, and repair.
To calculate the energy available from a food,
multiply the number of grams of carbohydrate,
protein, and fat by 4, 4, and 9, respectively. Then
add the results together.
For example, 1 slice of bread with 1 tablespoon of
peanut butter on it contains 16 grams
carbohydrate, 7 grams protein, and 9 grams fat:
16 g carbohydrate ₓ 4 kcal/g= 64 kcal
7 g protein ₓ 4 kcal/g= 28 kcal
9 g fat ₓ 9 kcal/g =81 kcal
Total 173 kcal.
Dietary Reference Intakes (DRIs)
Dietary Reference Intakes (DRIs)
A set of nutritional reference values that applies
to healthy people.
The DRIs for most nutrients consist of four values:
• Estimated Average Requirement (EAR)
• Recommended Dietary Allowance (RDA)
• Adequate Intake (AI)
• Tolerable Upper Intake Level (UL)
Estimated Average Requirement (EAR) The
average daily nutrient intake level estimated to
meet the requirement of half of the healthy
individuals in a particular life stage or gender
group.
Recommended Dietary Allowance (RDA) The
average daily amount of a nutrient considered
adequate to meet nutrient needs of healthy
individuals in a particular life stage and gender
group.
Adequate Intake (AI)the average daily amount of a
nutrient that appears sufficient to maintain
nutrient needs of healthy individuals .
Its used as a guide for nutrient intake when an RDA
cannot be determined.
Tolerable Upper Intake Level (UL) The maximum
daily amount of a nutrient that appears safe for
most healthy people and has no adverse health
effects to individuals in a particular life stage and
gender group.
The Estimated Energy Requirement
(EER)
The Estimated Energy Requirement Is the Intake
Predicted to Maintain a Healthy Weight
The Estimated Energy Requirement (EER) is defined as
the average dietary energy intake that is predicted to
maintain energy balance in a healthy adult.
This dietary intake is defined by a person’s age, gender,
weight, height, and level of physical activity that is
consistent with good health. Thus, the EER for an active
person is higher than the EER for an inactive person
even if all other factors (age, gender, and so forth) are
the same.
Acceptable Macronutrient Distribution Ranges
(AMDR) A range of intakes for a particular
energy source that is associated with reduced
risk of chronic disease while providing
adequate intakes of essential nutrients.
Acceptable Macronutrient
Distribution Ranges (AMDR)
Proteins: Amino
Acids
Proteins are large, complex molecules made up of
amino acids found as essential components of all
living cells.
Although proteins are best known as a part of muscle
mass, they are in fact critical components of all
tissues of the human body, including bones, blood,
and hormones.
The proteins in our bodies are made from a
combination of building blocks called amino acids.
Proteins cont.
-Main structural materials in the body (l/6th)
-17% of the body weight •
-A major part of bones and muscles
-Important in blood, cell membranes, enzymes, and
immune factors
-Provide energy for the body-on average, 4 kcal/ gm
-The human body contains 30,000 different kinds of
proteins
-And about 3000 have been studied
Amino acids (AA)
They are smaller units of proteins
AA are found in food and stated to be needed by
the human body:
essential amino acids Amino: acids not produced
by the body so that they must be obtained
from food.
nonessential amino acids :Amino acids that can
be manufactured by the body in sufficient
quantities and therefore do not need to be
consumed regularly in our diet.
Essential and non-essential AA
functions of proteins
1-Proteins Contribute to Cell Growth, Repair, and Maintenance
-Red blood cells live for only 3 to 4 months and then are replaced by new cells
that are produced in bone marrow.
-The cells lining the intestinal tract are replaced every 3 to 6 days.
2-Proteins Act as Enzymes and Hormones.
Ex: the enzyme phosphofructokinase (PFK) break down glucose and use it for
energy during exercise.
-insulin, is a hormone facilitate the transport of glucose into cells.
-glucagon and thyroid hormone.
3-Proteins Maintain Fluid and Electrolyte Balance
When the level of proteins in the blood is insufficient, edema can result.
4-Proteins Maintain Acid–Base Balance
By buffering acids and bases, proteins maintain acid–base balance and blood
pH.
5-Proteins Maintain a Strong Immune System
Antibodies are special proteins that are critical components of
the immune system.
6-Proteins Serve as an Energy Source
Certain amino acids can be converted into glucose via
gluconeogenesis.
7-Proteins Assist in the Transport and Storage of
Nutrients
Transferrin is a transport protein which carries iron in the blood.
Ferritin, is an example of a storage protein: it is the compound in
which iron is stored in the liver.
Situations of protein supplementation
1-During growth phase of infancy
2-Donation of blood
3-Excessive menstruation
4-Hemorrhage after an accident
5-Destruction of tissues due to burn
6-Wasting diseases such as TB
7-Pregnancy and lactation
Protein requirement for vulnerable groups
-During pregnancy increased by about 14 g per day.
-During lactation by about 25 gm per day (during 0
to 6 months).
-Young children (0-6 years) require proportionately
more protein for each kilogram of body weight
than adults.
Questions