Lec 2 community dietary assessment

Dr. Siham M.O. Gritly 1

Community and Public Health Nutrition

2-Dietary Assessment

Prepared by: Dr. Siham 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.


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 intakesFood 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 :….


Assessment of individual intakes24 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


Assessment of individual 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/wk1-2/wk 2/mth or

lessNever

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 FFQFood 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 week


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 groupsThe 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 fruitsMilk/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

Lec 2 community dietary assessment

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