Nutrition

LEARNING OBJECTIVES
By the end of this lecture the reader should
be able to:
To know the concept of nutrition and classifications of food
To understand diet planning and dietary guidelines
To understand therapeutic nutrition
To know the different methods for assessing the nutritional
status
To understand the basic anthropometric techniques,
applications, & reference standards
To know hazards of obesity

INTRODUCTION
 Nutrition is the most important health promoting
factors.
 Good nutrition is an essential requirement for good
health.
 Adequate nutrition is the necessary first step for the
improvement of the quality of life.

Nutrition
 Science of Nutrition
 The study of food and the substances they contain
 The study of nutrients - their action, interaction and
balance – in relation to health and disease
 Nutrition means dynamic process in which food taken is
utilized (the process of providing the individual with
food).
 Food: derived from plant or animal sources
 Diet: the foods one consumes
 Nutrients: substances used by the body to supply energy,
promote growth and repair of body tissues and regulate body processes

Classification of foods
1. Organic or inorganic
2. Essential or nonessential
3. Macronutrients or micronutrients
4. Energy-yielding

1. Chemical composition of nutrients
 Inorganic Nutrients
 Minerals
 Water
 Organic Nutrients
 Carbohydrates
 Lipids
 Protein
 Vitamins

2. Classes of Essential Nutrients
 Carbohydrates
 Proteins
 Lipids
 Vitamins
 Minerals
 Water

3. Classified by the amount required for the body:
 Macronutrients: these are proteins, fats and
carbohydrates. They form the main bulk of food. They are
required by the body in relatively large amounts (measured in
grams)
 Micronutrients: these are vitamins and mineral. They are
called micronutrients because they are required in small
amounts (measured in milligrams or micrograms).

4. Energy-Yielding Nutrients
 Carbohydrates
 Proteins
 Lipids

Dietary fibres
 Are exclusively found in plant food, which the body cannot digest or
absorb into the blood stream, therefore cannot be properly
considered a nutrient.
 Basically, fiber is ingested into the body and expelled virtually intact
 Fibers is found in two forms;
1. Soluble fibers: dissolve in water
Sources : peas, and some fruits such as apple and orange, and several
vegetables including carrots, and cauliflower.
 Functions : binds to fatty substances and promotes their excretion, which
helps lower blood cholesterol levels.

Dietary fibres
2. Insoluble fiber is known as “ roughage “: do not dissolve in water
 Valuable of roughage :
•It is needed to form the bulk of the intestinal contents.
•It helps the intestine to perform its normal movements.
•It prevents constipation and cancer of the colon.
•It may also help reduce the risk of digestive problems, heart diseases,
diabetes, and promote weight loss.
 Sources: whole wheat products, wheat bran, corn bran, and many vegetables
including cauliflower, and green beans).
 Total recommended daily amount of dietary fiber:
 Between 25 to 35 grams from natural source foods.
 However, consuming excess amounts of fiber (more than 50 to 60 grams per
day) may cause a decrease in the amount of vitamins and minerals that body
absorbs, and can also cause flatulence, diarrhea.
 It should also be noted that the older we are, the more daily fiber required in
diet.

Characteristics of good food
 Adequate quantity and quality that satisfy
individual needs
 Safe, free of infection, toxicity and
allergens

How much do we need?
(Nutrient Recommendations)
 Dietary Reference Intakes: a set of nutrient
intake values used for planning and assessing
diets including:
1. Estimated Average Requirements
2. Recommended Dietary Allowances
3. Adequate Intakes
4. Tolerable Upper Limits

1. Estimated Average Requirement:
 The average daily amount of a nutrient needed in the
diet that will maintain physiological activities and reduce
disease risks
 Different criterion for each nutrient and each gender and
age group of people
2. Recommended Dietary Allowances (RDA):
 Estimates for average daily nutrient intakes which are
believed adequate to prevent deficiency

3. Adequate Intakes:
 A value used as a guide for sufficient nutrient intake
when there is insufficient scientific evidence to
establish a RDA
4. Tolerable Upper Intake Levels:
 The maximum daily amount of a nutrient that appears
safe for most healthy people

Estimated energy requirement
 The average dietary energy intake that maintains
energy balance in a healthy person of a given
age, gender, weight, height, and activity level
 Acceptable Macronutrient Distribution Ranges:
 Carbohydrate: 45% - 65%
 Fat: 20% - 35%
 Protein: 10% - 35%

Diet Planning Principles
1. Adequacy: providing sufficient energy and essential nutrients for
healthy people
2. Balance: consuming the right proportion of foods
3. Energy control: balancing the amount of foods and energy to sustain
physical activities and metabolic needs
4. Nutrient density: measuring the nutrient content of a food relative to
its energy content
5. Moderation: providing enough but not too much of a food or nutrient
6. Variety: eating a wide selection of foods within and among the major
food groups

Estimation of caloric needs
 There are several different formulas for determining
estimated caloric needs. All are based on the principles of
energy balance: Energy being used up or expended
throughout the day should be equally consumed for weight
maintenance.
 Weight loss occurs when energy intake is lower than
estimated energy output, and weight gain occurs when
energy intake is greater than estimated energy output.
 Many different factors effect someone's energy output, such
as age, sex, height, weight and energy level. It is important
to determine daily caloric intake, to achieve the right energy
input balance to suit your lifestyle.

Resting Energy
 Caloric intake equations are based on determining a person's resting
energy expenditure.
 This is the energy necessary to sustain life and to keep the heart,
lungs, brain, liver and kidneys functioning properly.
 Resting energy expenditure accounts for about 60 to 75 percent of
total daily energy expenditure.
 The remaining energy expenditure is through physical activity,
about 25 percent, and through the metabolic process of digesting
food, about 10 percent

 Mifflin-St. Jeor equation (modified Harris-Benedict
Equation):
 Resting Metabolic Rate(RMR)=
 for females= 10 x (Weight in kg) + 6.25 x (Height in cm) - 5 x (age in
years) – 161
 for males= 10 x (Weight in kg) + 6.25 x (Height in cm) - 5 x (age in
years) + 5.
 These equations are also multiplied by the same physical activity factors
to estimate daily kilocalories needed.
 Little to no exercise: RMR x 1.2
 Light exercise (1–3 days per week): RMR x 1.375
 Moderate exercise (3–5 days per week): RMR x 1.55
 Heavy exercise (6–7 days per week): RMR x 1.725
 Very heavy exercise (twice per day, extra heavy workouts): RMR x 1.9

The food pyramid
(dietary guidelines)
 Definition: The food Pyramid Guide was designed to
establish recommended Dietary Guidelines, and contains
the building blocks essential to a healthy diet.
 It has the guidance required to recognize what and how
much to eat of the five major food groups.

The food pyramid
(dietary guidelines)
 Importance:
 Keep our fat intake and total cholesterol at
recommended levels, and identify the essential
nutrients that make up a healthy diet for
maintaining our fitness.
 Balance the food groups in our diet.
 Supply a nutrition equilibrium by keeping total
calorie count in line with weight loss and weight
management goals.

Food Exchange system list
 It provide a framework to group foods with similar carbohydrate,
protein, fat, and calorie contents
 Each list is a group of measured or weighed foods of approximately
the same nutritional value .
 The word exchange refers to the food items on each list which may be
substituted with any other food item on the same list.
 One exchange is approximately equal to another in carbohydrate,
calories, protein and fat within each food list.
 The exchange lists are used for weight management as well for
diabetes management.

Therapeutic nutrition
 Therapeutic nutrition refers to the use of diet as a therapeutic tool in the
management of patients.
 The major effort of all therapeutic nutritional program is to insure total adequacy of
good nutrition, prevent deficiencies and correct abnormal nutritional states.
 In constructing a diet for a patient, it is necessary to take into account the following
three factors:
 the normal daily needs of the patient.
 Previous nutritional depletion.
 Increased requirements resulting from current losses as by vomiting and
diarrhea.
 The composition of a patient’s diet should not be based upon the recommended
daily dietary allowances for healthy people because this does not take into account
the additional demands for specific nutrients.

 The caloric content of a diet, is determined by calculating:
 the total number of calories normally required by the patient.
 The amount of calories lost from the system by vomiting and diarrhea or form
the skin in burns.
 Extra needs produced by fever and other metabolic causes.
 The amount needed to compensate for previous weight loss.
 The patient’s caloric status as determined by height and weight.
 The presence of edema should be taken into account when evaluating weight
to height status.

 Modifications in conscistency and Texture of foods:
1. Clear liquid diet:
 The diet is highly restrictive and is of little nutritive value; it provide some electrolyte,
mainly sodium, chloride, and potassium.
 Indications for use: as a progression between IV feeding and a full liquid or solid diet
following certain types of surgery
 e.g. coffee, tea, fruit juices, carbonated beverages.
2. Full liquid diet:
 It provide an oral, nourishment that is well tolerated by patients who are actually ill or
who are unable to swallow.
 Indications for use: following oral surgery or plastic surgery of the face and neck. In
patients with esophageal strictures, and following mandibular fractures.
 E.g.: milk, eggs, vegetable’s juices.

 Modified fiber diet: which is classified
1. Fiber restricted diet:
 A diet that contains a minimum of fiber and connective tissue.
 Indications: During acute phase of diverticulosis, ulcerative colitis or
infectious enterocolitis when the bowel is inflamed.
2. High fiber diet:
 A diet that contains increased amounts of cellulose, semicellulose and
pectin.
 Indications: in constipation, uncomplicated diverticulosis and the irritable
bowel syndrome.

 Modification in protein contents:
1. High protein, high kilocalories diet:
 Provides a level of total kilocalories and protein substantially above that which is normally
required.
 Indications: Protein kilocalorie reduction, catabolic state, anorexia nervosa.
2. Controlled protein, potassium, sodium diet:
 The dietary intake of Na. K and protein are carefully regulated from day to day.
 Indications: When the glomerular filtration rate below 20-30 ml/minute. For the patients
not receiving dialysis severe restrictions are necessary.
 Modification in carbohydrate contents:
 Carbohydrate restricted diet for the management of the dumping syndrome.
 Galactose free diet.
 Lactose free diet.
 Sucrose restricted diet.
 Modifications in fat contents:
 Fat restricted diet.

Diagnostic category Diet Order Comment
Peptic ulcer Diet individualized for patient
tolerance with small frequent feedings
Consult dietitian to obtain patient
tolerance; restriction of caffeine, black
pepper and alcohol.
Constipation, diverticulosis,
haemorrhoids
High fiber diet Includes whole grain bread and cereals,
fresh and dried fruits, raw vegetables.
Hepatitis Regular diet High calories, high protein diet
encouraged.
Acute liver failure Trace protein, fat free diet Specify grams protein and fat; initially
8-10 gm protein and approximately
2gm fat suggested consists mainly of
fruits and fruit’s juices.
Renal disorder, renal insufficiency Protein, sodium, potassium, fluid
restricted
Post-transplant (kidney) High protein, low sodium, low sugar
diet, low calories to prevent weight
gain
1-2 gm sodium and 120-150 gm protein

Diagnostic category Diet Order Comment
Congestive heart failure Sodium restricted diet 0.5-1 gm sodium
Hypertension Sodium restricted diet 2-3 gm sodium
Myocardial infarction Progress from clear liquid to a low fat,
soft-sodium restricted diet with small
frequent feedings as tolerated; initially
no hot or cold foods or caffeine.
2gm sodium
40 gm fat
Hypercholestrerolaemia Low cholesterol, low fat diet Less than 300 mg cholesterole, 25-
30% calories as fat.
Hypertriglyceridaemia Moderate restriction in total fat;
sucrose and alcohol restricted, calories
for ideal body weight
30-35% calories as fat with complex
carbohydrate such as fresh fruits,
vegetables starsh.
Diabetes mellitus (non insulin
dependent)
Sucrose and saturated fat restricted
diet. Calories for ideal body weight
Specific calories. % of protein,
carbohydrate and fat; 50%
carbohydrate, 30% fat and 20%
protein
Diabetes mellitus
(insulin dependent)
As above + daily distribution of
carbohydrate
As above + specify type and timing of
insulin; complex carbohydrate such as
vegetables, fresh fruits.

Lecture Two
The nutritional status of an individual
is often the result of many inter-
related factors.
It is influenced by food intake,
quantity & quality, & physical health.
The spectrum of nutritional status
spread from obesity to severe
malnutrition

Nutritional Assessment Why?
The purpose of nutritional assessment is
to:
Identify individuals or population groups
at risk of becoming malnourished
Identify individuals or population groups
who are malnourished
To develop health care programs that meet the
community needs which are defined by the
assessment
To measure the effectiveness of the nutritional
programs & intervention once initiated

Methods of Nutritional Assessment
Nutrition is assessed by two types of
methods; direct and indirect.
The direct methods deal with the
individual and measure objective
criteria, while indirect methods use
community health indices that
reflects nutritional influences.

Direct Methods of Nutritional
Assessment
These are summarized as ABCD
 Anthropometric methods
 Biochemical, laboratory methods
 Clinical methods
 Dietary evaluation methods

Indirect Methods of Nutritional
Assessment
These include three categories:
Ecological variables including crop
production
Economic factors e.g. per capita
income, population density & social
habits
Vital health statistics particularly
infant & under 5 mortality & fertility
index

Anthropometric Methods
Anthropometry is the measurement of
body height, weight & proportions.
It is an essential component of clinical
examination of infants, children &
pregnant women.
It is used to evaluate both under & over
nutrition.
The measured values reflects the
current nutritional status & don’t
differentiate between acute & chronic
changes .

Anthropometric Measurements
 Height: Adults
 Length:
 Infants,
 < 24 months
 Weight
 % Usual body
weight
 % Ideal body weight
 BMI
 Mid-arm circumference
 Skin fold thickness
 Head circumference
 Assesses brain
development
 < 3 years of age
 Head/chest ratio
 Waist/hip ratio

Anthropometry for children
Accurate measurement of height and
weight is essential. The results can
then be used to evaluate the physical
growth of the child.
For growth monitoring the data are
plotted on growth charts over a period
of time that is enough to calculate
growth velocity, which can then be
compared to international standards

Growth Monitoring Chart
Percentile chart

Measurements for adults
Height:
The subject stands erect & bare
footed on a stadiometer with a
movable head piece. The head
piece is leveled with skull vault
& height is recorded to the
nearest 0.5 cm.

WEIGHT MEASUREMENT
Use a regularly calibrated electronic
or balanced-beam scale. Spring
scales are less reliable.
Weigh in light clothes, no shoes
Read to the nearest 100 gm (0.1kg)

Nutritional Indices in Adults
 The international standard for assessing
body size in adults is the body mass index
(BMI).
 BMI is computed using the following
formula: BMI = Weight (kg)/ Height (m²)
 Evidence shows that high BMI (obesity level)
is associated with type 2 diabetes & high risk
of cardiovascular morbidity & mortality

BMI (WHO - Classification)
 BMI < 18.5 = Under Weight
 BMI 18.5-24.9= Healthy weight range
 BMI 25-30 = Overweight (grade 1
obesity)
 BMI >30-40 = Obese (grade 2 obesity)
 BMI >40 =Very obese (morbid or
grade 3 obesity)

Waist/Hip Ratio
 Waist circumference is measured
at the level of the umbilicus to
the nearest 0.5 cm.
The subject stands erect with
relaxed abdominal muscles, arms
at the side, and feet together.
The measurement should be
taken at the end of a normal
expiration.

Waist circumference
Waist circumference predicts mortality better
than any other anthropometric
measurement.
It has been proposed that waist
measurement alone can be used to assess
obesity, and two levels of risk have been
identified
MALES FEMALE
LEVEL 1 (accepted) > 94cm > 80cm
LEVEL2 (obesity) > 102cm > 88cm

Hip Circumference
Is measured at the point of greatest
circumference around hips & buttocks to
the nearest 0.5 cm.
The subject should be standing and the
measurer should squat beside him.
Both measurement should taken with a
flexible, non-stretchable tape in close
contact with the skin, but without
indenting the soft tissue.

Interpretation of WHR
High risk WHR= >0.80 for females &
>0.95 for males i.e. waist
measurement >80% of hip
measurement for women and >95%
for men indicates central (upper
body) obesity and is considered high
risk for diabetes & CVS disorders.
A WHR below these cut-off levels is
considered low risk.

ADVANTAGES OF ANTHROPOMETRY
 Objective with high specificity &
sensitivity
 Measures many variables of nutritional
significance (Ht, Wt, MAC, HC, skin fold
thickness, waist & hip ratio & BMI).
 Readings are numerical & gradable on
standard growth charts
 Readings are reproducible.
 Non-expensive & need minimal training

Limitations of Anthropometry
Inter-observers errors in
measurement
Limited nutritional diagnosis
Problems with reference standards,
i.e. local versus international
standards.
Arbitrary statistical cut-off levels for
what considered as abnormal values.

Biochemical (laboratory)
assessment
 Provides information about
 Protein-energy nutrition
 Vitamin & mineral status
 Fluid & electrolyte balance
 Organ functioning

Biochemical (laboratory)
assessment
Hemoglobin estimation is the most
important test, & useful index of the
overall state of nutrition. Beside
anemia it also tells about protein &
trace element nutrition.
Stool examination for the presence of
ova and/or intestinal parasites
 Urine dipstick & microscopy for
albumin, sugar and blood

Specific Lab Tests
Measurement of individual nutrient
in body fluids (e.g. serum retinol,
serum iron, urinary iodine, vitamin
D)
Detection of abnormal amount of
metabolites in the urine (e.g. urinary
creatinine/hydroxyproline ratio)
Analysis of hair, nails & skin for
micro-nutrients.

Advantages of Biochemical Method
It is useful in detecting early changes
in body metabolism & nutrition before
the appearance of overt clinical signs.
It is precise, accurate and
reproducible.
Useful to validate data obtained from
dietary methods e.g. comparing salt
intake with 24-hour urinary excretion.

Limitations of Biochemical Method
Time consuming
Expensive
They cannot be applied on large scale
Needs trained personnel & facilities

CLINICAL ASSESSMENT
It is an essential features of all
nutritional surveys
It is the simplest & most practical
method of ascertaining the nutritional
status of a group of individuals
It utilizes a number of physical signs,
(specific & non specific), that are
known to be associated with
malnutrition and deficiency of vitamins
& micronutrients.

CLINICAL ASSESSMENT/2
Good nutritional history should be
obtained
General clinical examination, with
special attention to organs like hair,
angles of the mouth, gums, nails,
skin, eyes, tongue, muscles, bones,
& thyroid gland.
Detection of relevant signs helps in
establishing the nutritional diagnosis

CLINICAL ASSESSMENT/3
 ADVANTAGES
Fast & Easy to perform
Inexpensive
Non-invasive
 LIMITATIONS
Did not detect early cases

Clinical signs of nutritional deficiency
HAIR
Protein, zinc, biotin
deficiency
Spare & thin
Protein deficiencyEasy to pull out
Vit C & Vit A
deficiency
Corkscrew
Coiled hair

MOUTH
Riboflavin, niacin, folic acid,
B12 , pr.
Glossitis
Vit. C,A, K, folic acid & niacinBleeding & spongy gums
B 2,6,& niacinAngular stomatitis,
cheilosis & fissured
tongue
Vit.A,B12, B-complex, folic
acid & niacin
leukoplakia
Vit B12,6,c, niacin ,folic acid
& iron
Sore mouth & tongue

EYES
Vitamin A deficiencyNight blindness,
exophthalmia
Vit B2 & vit A
deficiencies
Photophobia-
blurring,
conjunctival
inflammation

NAILS
Iron deficiencySpooning
Protein deficiencyTransverse lines

SKIN
Folic acid, iron, B12Pallor
Vitamin B & Vitamin CFollicular
hyperkeratosis
PEM, Vit B2, Vitamin A,
Zinc & Niacin
Flaking dermatitis
Niacin & PEMPigmentation,
desquamation
Vit K ,Vit C & folic acidBruising, purpura

Thyroid gland
 in mountainous
areas and far from
sea places Goiter is
a reliable sign of
iodine deficiency.

Joins & bones
 Help detect signs of
vitamin D
deficiency (Rickets)
& vitamin C
deficiency (Scurvy)

DIETARY ASSESSMENT
 Nutritional intake of humans is
assessed by five different methods.
These are:
 24 hours dietary recall
 Food frequency questionnaire
 Dietary history since early life
 Food dairy technique
 Observed food consumption

24 Hours Dietary Recall
A trained interviewer asks the
subject to recall all food & drink
taken in the previous 24 hours.
It is quick, easy, & depends on short-
term memory, but may not be truly
representative of the person’s usual
intake

Food Frequency Questionnaire
In this method the subject is given a
list of around 100 food items to
indicate his or her intake (frequency &
quantity) per day, per week & per
month.
inexpensive, more representative &
easy to use.

Limitations:
 long Questionnaire
 Errors with estimating serving size.
 Needs updating with new commercial
food products to keep pace with
changing dietary habits.

DIETARY HISTORY
It is an accurate method for
assessing the nutritional status.
The information should be collected
by a trained interviewer.
Details about usual intake, types,
amount, frequency & timing needs
to be obtained.
Cross-checking to verify data is
important.

FOOD DAIRY
Food intake (types & amounts)
should be recorded by the subject at
the time of consumption.
The length of the collection period
range between 1-7 days.
Reliable but difficult to maintain.

Observed Food Consumption
 The most unused method in clinical practice,
but it is recommended for research purposes.
 The meal eaten by the individual is weighed
and contents are exactly calculated.
 The method is characterized by having a high
degree of accuracy but expensive & needs time
& efforts.

Interpretation of Dietary Data
1. Qualitative Method
 using the food pyramid & the basic
food groups method.
 Different nutrients are classified
into 5 groups (fat & oils, bread &
cereals, milk products, meat-fish-
poultry, vegetables & fruits)
 determine the number of serving
from each group & compare it with
minimum requirement.

Interpretation of Dietary Data/2
2. Quantitative Method
 The amount of energy & specific nutrients
in each food consumed can be calculated
using food composition tables & then
compare it with the recommended daily
intake.
 Evaluation by this method is expensive &
time consuming, unless computing facilities
are available.

Food balance sheet
 Definition: It determines the individual
share from different foods assuming that
the available food is distributed equally
among people.
 Or the food balance sheet determines the
food consumption level per head per day
assuming adequate distribution.

Food balance sheet
 The food balance sheet is a method for:
 Assessment of National food consumption.
 Determining the individual share of food
consumption per day, assuming adequate
distribution for the available food.
 The first food balance sheet in Egypt was
conducted in 1947-1948.

Food balance sheet
 Advantages:
 It shows quantities and types of food available for
consumption.
 It can serve as an index for obvious deficit. Hence we can
develop and build the agriculture policy to meet the
nutritional requirement of the population.
 It can show to what extent the country dependent on others.
 It can be used to a certain extent for comparing the food
consumption level in different countries.
 When these data tabulated together along number of years,
it shows the pattern of diet and change in it.

Food balance sheet
 Basic feature (or pattern) of Egyptian
diet:
 Energy is more than average.
 Cereals (especially bread) form a good bulk of
diet and supply the greater part of energy,
protein, iron and vit. B.
 Animal food content is low.
 Protein intake is largely from plant sources.
 Iron intake is in excess, but largely from plant
origin with lower absorbability.
.

Nutrition

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