Lec 2 community dietary assessment

Community and Public Health
Nutrition
2-Dietary Assessment
Prepared by: Dr. Siham Gritly
1Dr. Siham M.O. Gritly

What is dietary assessments
• A dietary assessments are comprehensive
evaluation to assess food consumption at
national level, house hold level and a person's
food intake level.
• It is one of the tool for nutritional status
assessment.
• Dietary assessment includes;
• food supply
• production at the national level,
• food purchases at the household level,
• food consumption at the individual level.
Dr. Siham M.O. Gritly 2

Dietary Assessment Principles
Adequacy; a diet that provides enough energy
and nutrients to meet the needs according to
the recommended dietary intakes/ allowances
Balance : a diet that provides enough, but not
too much of each type of food ( adequacy of
basic 6 food groups)

Variety; a diet that includes a wide selection of
foods within each food group
Nutrient Density : a diet that includes foods that provide
the most nutrients for the least number of calories
(nutrient dense foods)
Moderation : A diet that limits intake of foods high in
sugar and fat (nutrient intake guidelines)

There are different methods to assess dietary
intake;
• 1- National food supply data (Food balance
sheets)
• 2-Household data
• 3-Individual data
• 4-Rapid Assessment Procedure RAP

Methods of assessing dietary intake
• 1- National food supply data
• The most commonly used to assess food
consumption at national level are Food balance
sheets;
• Food balance sheets; provide data on food
availability for consumption (i.e food supply
within a country)

Ref. FAO
• It provides a comprehensive picture of the
pattern of a country’s food supply during a
specific reference period, calculated from;
• annual production of food,
• changes in stocks,
• imports and exports
• and distribution of food over various uses
within the country

Disadvantages of food balance sheet
• Do not measure the food actually ingested by
the population(e.g. people of different socio-
economic groups, ecological zones or
geographical areas within a country) but they
have been used to compare the adequacy of
food supply among countries to meet
requirements
• Do not provide information on seasonal
variations in the total food supply.

• 2-Household data
• Household food consumption is the food and
beverages available for consumption at household
level ,
• Disadvantages; excluding that eaten away from home
unless taken from the home.
• It does not provide information on consumption of
food by specific individuals within the household
level
• food consumption /capita is calculated sometimes
ignoring the age or gender distribution in the HH.

• Food consumption per capita can be calculated in
terms of;
• income level,
• number of meals eaten at home and away from home,
• family size
• region of the country;
• Estimates of nutrient intake per capita are calculated
by multiplying the average food consumption data by
the corresponding nutrient values for the edible
portion of the food.

National and household food consumption
Importance of household and food
consumption surveys data
• Data obtained through household and food consumption surveys
are often the preferred source of food consumption
estimates for most analysts because;
• 1- they provide more information on food consumption
than food balance sheets do.
• 2- the surveys collect data from the people who are
purchasing and eating the food,
• 3- they can obtain information on the consumption
characteristics of children, elderly people, males, females
and on rural compared with urban populations.

for the assessment of under-nutrition prevalence in a
country; There are two main approaches.
• 1-estimating the numbers of people whose dietary
energy supply is likely to fall below a certain
physiologically needs.
• 2-direct information on the nutritional status of
individuals
• Estimation of the distribution of energy
consumption among household is very valuable
indicators for nutrients deficiencies.

• 3-Individual data
• Includes;
• Food records,
• 24 hr dietary recall,
• FFQs, diet histories,
• food habit questionnaires,
• combined methods

Assessment of individual intakes
Food records
• Dietary records
• Record all foods and beverages consumed over a
specific time period (3-4 d)
• Amount consumed determined by weighing with
a scale or measuring volume using standard cups
and spoons
• special foods may be recorded (fat, vitamin A,
iron rich)
• Total energy intake will require all foods to be
recorded.

Food Diary a food record is usually almost accurate if the
food eaten is recorded the same day; the individual’s nutrient
intake is calculated and averaged at the end of the desired
period (usually 3-7 days) and then compared with dietary
reference intakes (DRIs)
Meal Foods ( list ) Amount
eaten
How
prepared
Where eaten
(home, work,
etc)
Breakfast
Snack
Lunch
Tea
Dinner
Food supplements :
Name…… (cans/d)
Vitamins/minerals supplement
:….

24 hr dietary recall
• The 24 hr recall requires individuals to
remember the specific foods and amounts of
foods they consumed in the past 24 hours;
• the information is then analyzed by the person
or professional.
• Food intake per person or per consumption
unit is calculated taking into account the age ,
sex and the number of family members.

• method of preparation; (boiled/baked/fried);
• brand name (commercial/ready to eat/parts eaten
(whole item/half);
• ingredients(if mixed dish, what ingredients used and
amounts;
• addition to foods ( was anything added to food during
preparation or at the table; was any dressing added,
cream or sugar)

• Get an accurate and complete listing of all
food/drink individual consumed within last 24
hrs
• Questions asked:
– What food/drink was consumed?
– How much was consumed?
– Time it was consumed?
– How was it prepared?
– How was it served?
– Details of food (e.g low fat, 1%, whole, milk
powder, preparation, )

Limitation of 24 hours recall
• Relies on memory;
• requires skilled interviewer;
• does not reflect the usual dietary intake ;
• tendency to over report low intakes and under
report high intakes

FFQs, diet histories
FF is a retrospective review of intake frequency
– that is food consumed per day, week, per 15
days, per month.
Report usual frequency of consumption of each
food item from a list of food items in reference
to a specified period (past wk/mo/yr)

organizes foods into groups that have common
nutrients
Face to face interview, telephone or by self
administration
Describes dietary patterns or food habits not
nutrient intake
Semi quantified tools can obtain information on
portion size using household measures

Example; Food Frequency Questionnaire
Food item > 1/d 1/d 3-6
times/wk
1-2/wk 2/mth or
less
Never
Beef
Fish
Liver
Poultry
Eggs
Dried beans
Green leafy
vegetables
Enter other foods not listed that are
eaten regularly
1.-------------
2. -------------
3. ----------
-

Food Frequency Questionnaire

Limitation of Food Frequency Questionnaire
• Relies on memory;
• requires complex calculations to estimate
frequencies;
• requires literacy,
• doe not quantify intake

Example of semi quantitative FFQ
Food Medium
serving
Serving How often ?
S M L D W M Y N
Apples,
apple
sauce
1 or ½ cup
Banana 1 medium
Papaya ¼ medium
Water
melon
1 slice
Orange 1 medium
Bel juice 6 oz glass
Coconut
water
4 oz glass
Boroi ½ bati

• Semi quantitative food frequency questionnaires
provide the respondent with a food list.
• Semi quantitative food frequency questionnaires
estimate individual intakes quantitatively.
• Nutrient intakes from semi quantitative food
frequency questionnaires usually are overestimated.
• Measures of usual energy intakes for accurate
groups specified by sex and age obtained by other
methods

• 4-Rapid Assessment Procedure RAP
• focus groups to gather information on food
behaviors, beliefs and intakes
• Rapid assessment procedures (RAP) are a reality
in international health, nutrition, and development
planning
• Planning and implementing development
programmes with people's participation is
considered one of the keys to sustainable
development as suggested by experts.

Estimating average intake of nutrients
• Specification of portion size
• Description of portion size – small, medium, large
• Information on frequency and serving size allows for
estimating nutrient intakes
• Food list should contain foods that contribute to majority of
the nutrients/specific in the diet (represent 75% of the
nutrient intake –selected nutrients)
• % adequacy of food groups
• % adequacy of RDA for energy and nutrients including
micronutrients
• Used in epidemiological research to study diet disease
relationships

• Epidemiology is a study of the relationship
between possible determining factors and the
distribution of the frequency of disease in
human populations

Estimated nutrient intakes must be compared with
appropriate references;
Dietary Reference Intakes (DRIs).
The DRIs encompass four types of nutrient
reference values, each with different uses
• These values are used for planning and
assessing diets include:
• Estimated Average Requirements (EAR),
• Recommended Dietary Allowances (RDA),
• Adequate Intakes (AI),
• Tolerable Upper Intake Levels (UL).

• Estimated Average Requirement (EAR) -
the amount of a nutrient that is
estimated to meet the requirement of
half of all healthy individuals in a given
age and gender group.

• Recommended Dietary Allowance
(RDA) - the average daily dietary intake
of a nutrient that is sufficient to meet the
requirement of nearly all (97-98%)
healthy persons.
• This is the number to be used as a goal
for individuals. It is calculated from the
EAR.

• Adequate Intake (AI) - only established when
an EAR (and thus an RDA) cannot be
determined because the data are not clear-cut
enough; a nutrient has either an RDA or an AI.
• The AI is based on experimental data or
determined by estimating the amount of a
nutrient eaten by a group of healthy people and
assuming that the amount they consume is
adequate to promote health.

• Tolerable Upper Intake Level (UL) -
the highest continuing daily intake of a
nutrient that is likely to pose no risks of
adverse health effects for almost all
individuals.
• As intake increases above the UL, the
risk of adverse effects increases

Nutrition Recommendations from
(WHO/FAO, 2003)
• The World Health Organization (WHO/FAO)
has assessed the relationships between diet and
the development of chronic diseases. Its
recommendations include (look table next slide)

Ranges of nutrient intake goals (WHO/FAO, 2003)
Dietary factor Goal (% of total energy )
Energy: sufficient to support growth, physical
activity, and a healthy body weight
(BMI between 18.5 and 24.9) and to
avoid weight gain greater than 11
pounds (5 kilograms) during adult life
Total fat: 15 to 30 percent of total energy
Saturated fatty acids <10 percent of total energy
Polyunsaturated fatty acids 6 to 10 percent of total energy
Omega-6 polyunsaturated fatty
acids:
5 to 8 percent of total energy
Omega-3 polyunsaturated fatty
acids:
1 to 2 percent of total energy

Ranges of nutrient intake goals (WHO/FAO, 2003)
Dietary factor Goal (% of total energy )
Trans-fatty acids: <1 percent of total energy
Total carbohydrate: 55 to 75 percent of total energy
Sugars: <10 percent of total energy
Protein: 10 to 15 percent of total energy
Cholesterol: <300 mg per day
Salt (sodium): <5 g salt per day (<2 g sodium
per day), appropriately iodized
Fruits and vegetables: ≥400 g per day (about 1 pound)
Total dietary fiber: >25 g per day from foods
Physical activity: one hour of moderate-intensity
activity, such as walking, on
most days of the weekDr. Siham M.O. Gritly 37

Study Designs
A Cross-Sectional Surveys
adapted from;Martin Eastwood. Principles of Human Nutrition; Second edition 2003 by Blackwell
Science Ltd, a Blackwell Publishing Company
• One of the most common types of population-
level studies is the cross-sectional survey, a set
of measurements of a population at a particular
point in time.
• Such data can be collected only to describe a
particular population’s intake.
• for assessing risk of deficiency, toxicity, and
overconsumption;

• Alternatively, data of this type of survey can
be used for surveillance at;
• the national,
• state,
• local levels
• Main objectives is;
• to evaluate adherence to dietary guidelines
and public health programs;
• and to develop food and nutrition policy.

• Cross-sectional data also may be used for
examining associations between current diet
and other factors including health.
• caution must be applied in examining many
chronic diseases believed to be associated with
past diet because the currently measured diet is
not necessarily related to past diet

• Some of the instruments, such as;
• the 24-hour recall, are appropriate when
the study purpose requires quantitative
estimates of intake.
• Others, such as FFQs or behavioral indicators,
are appropriate when qualitative estimates are
sufficient—for example, frequency of
consuming soda and frequency of eating from
fast-food restaurants.

Case-Control (Retrospective) Studies
• A case—control study design classifies
individuals with regard to current disease
status (as cases or controls) and relates this to
past (retrospective) experience.
• the period of interest could be either;
• the recent past (e.g., the year before diagnosis)
• or the distant past (e.g., 10 years ago or in
childhood).

• the 24-hour recall, are not useful in
retrospective studies.
• The food frequency and diet history
methods are well suited for assessing past
diet and are therefore the only viable
choices for case—control (retrospective)
studies.

Cohort (Prospective) Studies
• In a cohort study design, exposures of interest
are assessed at baseline in a group (cohort) of
people and disease outcomes occurring over
time (prospectively) are then related to the
baseline exposure levels. In prospective
dietary studies, dietary status at baseline is
measured and related to later incidence of
disease.

• For many chronic diseases, large numbers of
individuals need to be followed for years before
enough new cases with that disease accrue for
statistical analyses.
• A broad assessment of diet is usually desirable in
prospective studies because many dietary
exposures and many disease end points will
ultimately be investigated and areas of interest
may not even be recognized at the beginning of a
cohort study

• In order to relate diet at baseline to the eventual
occurrence of disease, a measure of the usual
intake of foods by study subjects is needed.
• a single 24-hour recall or a dietary record for a
single day would not adequately characterize the
usual diet of individual study subjects in a cohort
study, such information could be later analyzed at
the group level for contrasting the average
dietary intakes of subsequent cases with those
who did not acquire the disease.

Intervention Studies
• Intervention studies range from relatively small, highly
controlled, clinical studies of targeted participants to
large trial of population groups.
• Intervention studies may use dietary assessment for
two purposes:
• (1) initial screening for inclusion (or exclusion) into the
study
• (2) measurement of dietary changes resulting from the
intervention.
• Not all intervention trials require initial screening.
• For those that do, screening can be performed using
very detailed instruments or less difficult instruments.

Dietary Assessment Methods Commonly Used in
Different Study Designs
adapted from;Martin Eastwood. Principles of Human Nutrition; Second edition 2003 by Blackwell
Science Ltd, a Blackwell Publishing Company
Study design Methods
Cross-sectional 24-Hour recall, FFQ, brief
instruments
Case—control
(retrospective)
FFQ, diet history
Cohort (prospective) FFQ, diet history, 24-hour
recall, dietary record
Intervention FFQ, brief instruments, 24-hour
recall

Dietary Assessment in different study
design
• Questions that must be answered in evaluating
which dietary assessment tool is most appropriate
for a particular research need include the
following:
• (1) Is information needed about
foods, nutrients, other food components, or
specific dietary behaviors?
• (2) Is the focus of the research question on
describing intakes using estimates of average
intake, and does it also require distributional
information?

• (3) Is the focus of the research question on
describing relationships between diet and
health outcomes?
• (4) Is absolute or relative intake needed?
• (5) What level of accuracy is needed?
• (6) What time period is of interest?
• (7) What are the research constraints in terms
of money, interview time, staff, and respondent
characteristics?

Food groups
The foods have been classified in the following
food groups
• Cereals and their products
• Starchy roots, tubers and their products
• Legumes and their products
• Vegetables and their products
• Fruits and their products
• Nuts, seeds and their products

Food groups
• Meat, poultry and their products
• Eggs and their products
• Fish and their products
• Milk and their products
• Fat and oils
• Beverages
• Miscellaneous

Easy way to count your calories (Measures
providing 100 kcal
Cereals : 30 g ( 1/5 cup)
Bread : 40 g ( 2 slices)
Pulses : 30 (2 Tbsp)
Leafy vegetables (sak): 250 g ( 2
small bunches)
Other vegetables : 400 g (4 cups)
Potato : 100 ( 1 cup)
Nuts/oilseeds : 20 g (handful)
Fruit : 150 g/ 1-2 fruits
Milk/Curd :150 ml ( 1 cup)
Butter milk : 670 ml ( 4 cups)
Channa/paneer/cheese : 30 g (1
pkt)

Easy way to count your calories (Measures
providing 100 kcal
• Egg : 60 g ( 1 medium size)
• Chicken : 90 g ( 3 small pieces)
• Mutton (animal protein): 85 g
• Fish (lean) 100 g
• Fish (fatty) 60 g
• Shrimp : 30 g
• Prawn : 100 g
• Sugar : 25 g ( 5 tsp)
• spice : 40 g ( 6 tsp)
• Oil/ghee : 10 g (2 tsp)
• Butter : 15 g (1 Tbsp

Food composition tables
• The conversion of food consumption to
nutrient intake is a complex process which
requires chemical analyses of the various food
constituents,
• food composition tables must include the
following.

• Foods included in the table must be
comprehensive and appropriate for the
population studied.
• The number of nutrients included in the table
for each food must be sufficient for the study
in question
• The method of expression of amounts of
nutrients must be specified
• Nutritionally appropriate methods must be
used for the estimation of each nutrient

• The disadvantage of using food composition
tables and nutrient databases is that;
• each value is the average of a limited number
of samples analyzed for each food.
• Sampling errors are large, especially for
mixed food dishes and meals.
• These add to the total error and variation in
results from dietary intake studies.

• FOOD AND AGRICULTURE ORGANIZATION
OF THE UNITED NATIONS Rome, 2001
• ANN M. COULSTON, CAROL J. BOUSHEY, MARIO G. FERRUZZI,
NUTRITION IN THE PREVENTION AND TREATMENT OF DISEASE
THIRD EDITION. Academic Press is an imprint of Elsevier
•
• Eastwood. Principles of Human Nutrition;
Second edition 2003 by Blackwell Science Ltd, a
Blackwell Publishing Company

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