Slide 1

Lalita Bhattacharjee

Nutritionist

National Food Policy Capacity Strengthening Programme

Food and Agriculture Organization of the United Nations

Bangladesh

Presented on 5 July 2011

at the

Training Workshop on Food Security Concepts, Basic Facts and Measurement Issues

25 June to 7 July 2011

DIETARY ASSESSMENT AND LINKS WITH NUTRITIONAL ASSESSMENT # 6 C

Inter

1

OUTLINE

Introduction

National and household food consumption surveys

Individual dietary assessment

Rapid methods of dietary assessment, micronutrient assessment and FFQ

Validation of dietary assessment

Dietary diversity

Conversion of dietary intakes to nutrients

Conclusion

Dimensions and methods for assessing food security and under nutrition

MethodsAvailability of foodAccess to foodConsumption of foodUtilization of nutrientsFAO MethodHousehold income& expenditure surveysIndividual food consumption/ intake surveysAnthropometryQualitative measures of food security

DIETARY ASSESSMENT AND NUTRITIONAL ASSESSMENT

A DIETARY ASSESMENT is a comprehensive evaluation of a person's food intake. It is one of the established methods of nutritional assessment. Dietary assessment techniques range from food records to questionnaires and biological markers.

NUTRITIONAL ASSESSMENT is more comprehensive and includes d determining nutritional status by analyzing the individuals brief socio economic background, medical history, dietary, anthropometric, biochemical, clinical data and drug nutrient interactions

NUTRITIONAL STATUS is the measurement of the extent to which an individuals physiologic need for nutrients is being met

NUTRIENT INTAKE depends on actual food consumption which is influenced by factors such as economic situation, eating behaviour, emotional climate, cultural influences, effects of disease states on appetite and the ability to absorb nutrients

NUTRIENT REQUIREMENTS are determined and influenced by age, sex, BMR, physiological status, activity patterns, physiologic stressors (infection, disease) and psychological stress

OPTIMAL NUTRITIONAL STATUS

Source: Mahan and Stump, 2000

DIETARY ASSESSMENT PRINCIPLES

Adequacy : a diet that provides enough energy and nutrients to

meet the needs according to the recommended dietary allowances

for good health

Balance : a diet that provides enough, but not too much of each

type of food

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

Methods of assessing dietary intake

National food supply data

Household data

Individual data (Food records, 24 hr dietary recall, FFQs, diet histories,food habit questionnaires, combined methods

RAP - rapid assessment procedure ( focus groups to gather information on food behaviours, beliefs and intakes)

National and household food consumption

Food consumption data collected at national, HH or individual levels

Individual intake data required for assessing nutrient adequacy

Food supply and HH data can provide useful information

Food consumption assessment at national level based on FBS ( per capita availability, no individual variation in food intake)

Food supply data useful

National and household level consumption

Preferred source of food consumption surveys ( provide more information than FBS)

Provide consumption characteristics of specific vulnerable groups including those from urban /rural populations

HIES 2010

SHARE OF FOOD GROUPS AS % OF DIETARY ENERGY SUPPLIES

Source: Adapted from FBS, FAO, 2010

Comparative Per capita food intake (g) HIES 1991 -92 to 2010

The above table provides a graphical presentation of the per capita food intake in g with rural-urban break up from HIES 1991 -92 to HIES 2010. The trend in food consumption (intake) pattern over the past 30 years the total per capita food consumption (intake) in Bangladesh has increased steadily; an increase of 5.51% is noted in the last 5 yrs at the national level. Increase in food intake over the years could attributed to increases in food production, coupled with an improvement of socio-economic status of the people. While the intake in urban households has been higher than rural, the current per capita intake shows a higher level among rural than urban populations.

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Per capita/d intake of major food items (g)

Consumption of food items is highly dependent on availability of food, price levels, food habits and ultimately purchasing behaviour. That the consumption of rice shows a relative decline in relation to an increase in total food intake is indicative of diversification of diets in Bangladesh, though at a slow pace. A decrease from 461 g/d in 2005 to 442 g cereals in 2010 is noted. A decrease of 2.1% is noted where Cer En % now contributes to 66% dietary energy compared to a previous contribution of 68%. Consumption of rice has decreased to 416g in 2010 from 440 g in 2005 which amounts to a decrease of 5.37% of rice En in the diet. Intake of animal foods rich in protein and micronutrients has increased to 109 g/capita/d in 2010 from 95 g in 2005. This amounts to an increase of nearly 15 % over the period. Similarly the intake of vegetables and fruits has increased to 211 g from 190 g per capita/d which amounts to an increase of 11% over the period. Pulses which are an important source of protein has remained almost the remain and continues to be much below the requirement. The production of pulses has been steadily declining due to the land being competed for production of other crops. The import of pulses has also not increased. Consumption of edible oil has increased by 25% (almost ) which could be a source of concern if an increasing trend in consumption is continued. On the whole, diversification of diets merits attention and needs to be accelerated given its role in sustaining diets and enhancing delivery on nutrition outcomes.

by increasing intakes of

non-cereal foods, particularly meat, egg, potato, fruits and vegetables (Figure 3).

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Per capita dietary energy (kcal) intake (HIES, 2010)

The overall energy intake per capita/d significantly increased to 2318kal in 2010 from 2238 kcal in 2005 ( recording an increase of 3.56%) a finding markedly different from the previous surveys. While the increase is noted in both rural and urban areas, it has increased more in the rural areas ( 2344 kcal in 2010 from 2253 kcal in 2005) with an increase of 91 kcal/d (4.06%) during this period. In the urban areas, it ahs increased to 2244kcal in 2010 from 2194 kcal in 2005 reflecting an increase of 51 kcal/d (2.31 %) during this period. Significant increase of per capita/d energy intake might be attributed to changing food habits, increase in income and subsequent purchasing power and availability of convenience foods on the shelf (small shops and markets in both urban and rural areas). The higher level of energy intake in the rural areas compared to the urban area could also be attributed to the higher energy requirements of the rural population given their occupation in heavy work related to agricultural labour and farm activities and rehabilitation work following the natural disasters, etc. Carrying out heavy work and physical activities demands higher calorie needs and food intake.

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Relative dietary energy contribution (En%) of cereals and rice to Bangladesh diet

Source/Year Energy intake (kcal)Cereal (g) En % Rice (g)En % HIES 2005 223845270% 440 68% HIES 2010 2318442 66% 41664%

Potential key indicators to be mapped at national &sub-national levels by sector : FOOD AND NUTRITION

Food intake indicators

Average energy intake

Average food intake of major food groups

Daily per caput protein intake

Percentage of energy from protein

Daily per caput carbohydrate intake

Percentage of energy from carbohydrates

Daily per caput fat intake

Percentage of energy from fat

Percentage of protein from animal source

Percentage of protein from vegetable source

Dietary Energy Supply

Percentage of undernourished population

Assessment of individual intakes

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

Specific/special foods may be recorded (fat, vitamin A, iron rich)

Total energy intake will require all foods to be recorded.

Assessment of dietary intakes at individual levels provides most useful information on the nutritional adequacy of diets. Need to record all foods and problem of omission is lessened and foods are described more fully. Requires motivated and literate respondents, which can limit its use in developing countries; recording foods as they are eaten can also affect both the type of food chosen and quantities consumed. This is a weakness, when the aim is to measure the usual dietary intake. However, when the aim is to enhance awareness of the dietary behaviour change as in some intervention studies, this effect can be seen as a strength. This method is taken to represent the gold standard and is used as a reference for validation of other methods.

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Assessment of individual intakes

24 hour recall :

Recall all the foods and beverages consumed the previous day or 24 hours prior to the interview

Interviewers should be knowledgeable about foods available in the market

Regional and ethnic preparations and methods

Interview conducted face to-face, structured w/o probing questions

Estimates of portion size are made using standardized cups and spoons

Record of food amounts converted into nutrient intakes using food composition tables

The validity of dietary recall has been studied by comparing reported intake with those recorded or weighed by trained observers. In general, group mean nutrient estimates from 24 hr recall were similar to observed intakes, although respondents with lower observed intake tended to over report and those with higher intakes tended to under report their past intakes. For some nutrients like VA with considerable variation in nutrient intake, there may be serious errors if one day recall is used to describe individual intakes. If groups are the focus of interest, the problem would be less.

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Assessment of individual intakes

Food frequency questionnaire (FFQ)

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)

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

Estimating average intake of nutrients

Specification of portion size standardized portions (Willet )

Description of portion size small, medium, large (Block)

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

% adequacy of food groups

% adequacy of RDA for energy and nutrients

Used in epidemiological research to study diet disease relationships

Assessment of individual intakes

Diet history

Collection of information on frequency of intake of various

foods and usual meal pattern

Entails detailed listing of foods and beverages

consumed at each eating session

3 d - diet record as an independent check on food intake

Methods of preparation

Rapid methods for community dietary assessment

Dietary assessment of HHs with children under 5s

Rapid assessment survey (focus group interviews, selected target group interviews IYCF practices,

Social customs and food beliefs, behaviours & intakes

Key informants community leaders, local shop owners or health personnel

Small clusters of women 5-6 women sufficient for FGD

development of culture -specific relevant food usage list

Linking food intake data with weighing /measuring of children & mother

Derive mothers BMI from standard tables

Strengths and limitations of dietary assessment methods

Relies on memory; may require trained interviewer ( need for food list & community based training

No literacy needed;

Diet history

may rely on memory; may require trained interviewer ( need for food list; std menu types; community based training)

Rapid &low cost; does not alter intake behaviour

Food habit questionnaire

Relies on memory; requires complex calculations to estimate frequencies; requires literacy, doe not quantify intake ( need for exhaustive food list; need for manual tally type calculations)

Inexpensive ; preferred for nutrients with high day-to-day variability; does not alter intake behaviour; lower respondent burden; epidemiological research to study diet-disease relationships

FFQs

Relies on memory; requires skilled interviewer; does not reflect the usual dietary intake

( need for food list, std menu types; need for community based training )

Immediate recall period, easy to obtain information; since interviewers administer tool & records the responses, literacy is not a problem, respondent burden minimal; does not alter intake behaviour; wide range of use

24 hr recall

High participation burden; requires literacy; may alter intake behaviour ( ?? community use )

Does not rely on memory; open ended

Food record

Limitations

Strengths

Method

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Selecting appropriate methods for community dietary assessment

RAP low cost, primary method for collecting dietary data (locally available /commonly consumed foods, dietary habits, behaviour)

Household surveys provide data on foods consumed by HH not individuals

Point to which foods are major contributors to nutrients of particular concern ( identify vulnerability/at risk of dietary deficiency - e.g no fresh vegetables/fruits, lack of DGLV/YOVlack of vitamin C & A in diet; inadequate presence of dietary enhancers for iron absorption??)

Food record and 24 hr recall methods of choice for estimating mean intakes

Combine with quantitative dietary intake methods to obtain individual nutrient intakes

Simplified assessment for specific nutrients

FFQ

Simple, short questionnaires

Assessing intakes of specific nutrients to study diet disease relationships

Questionnaires should focus on assessing intakes of specific nutrients (e.g calcium and osteoporosis, anti oxidants and CD cancer, heart disease, V&F and certain cancers, specific micronutrients and VAD, anemia; iodized salt, sea foods and fortified foods and IDD)

Questionnaires need to be tested in diverse populations to assess validity

VS, HKI Simplified FFQ

Validation of dietary methods

Need to establish validity and reliability

Validity - how well it measures what it purports to measure (accuracy)

Reliability how well it agrees on retesting under the same conditions (consistency)

Assessment of reliability is feasible , validity poses a problem

Gold standard established dietary record/direct observation of subjects consumption

Reference for validation

Relative validation

Unlike other methods, 24 hr recall is more susceptive to direct validation

Since time covered is short and limited, direct observation and measurements of intake are possible and also practical

Studies that compared 24 hr recall with observation and weighed duplicate meals have found that that the 2 methods yield similar results

Dietary intake varies from day to day, single recall may not be representative

Many studies confirm that variations within individuals, mean intake of group was not found to be significantly different from day to day

Inter individual variability is less marked than intra individual variation

Value of the method in establishing average intake levels of groups is reasonably well established

Errors in dietary surveys

RANDOM (reduced reliability)

Generate larger total variances

Reduce the statistical power to detect association between intake and a disease

Accentuate the estimates of possible associations

SYSTEMATIC (bias)

Represent greater hazards than random errors

Alter results

Very little can be done to correct for their effect

Structure of errors differs according to type of survey method

Methods relying on simple recall or ability to provide reliable estimates

of usual eating habits tend to be more prone to systematic errors while

methods that rely on direct measurement are associated with random errors

SOURCES OF ERROR IN DIETARY ASSESSMENT METHODS (INDIVIDUAL INTAKES)

Source of error Weighed food recordsEstimated food weight records24 hr recall Dietary history and FFQsFCT /recipe books + + + + Food coding + +++ Wrong weight of foods _ + ++Reporting error_ _ + + Variation of diet with time+ + +_Wrong frequency _ _ _ +Modified eating pattern_ _ Response biasSampling bias ++++

Source: Anna Ferro Luzzi in FAO, 2002

Some of these errors are shared by all methods; for example the quality of the FCT on which rests the precision for the estimation of energy and nutrient intake. Other errors are specific to one or another of the methods. A larger number of errors are associated with FFQ, dietary history method while the weighed food record appears to be least affected.

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Illustration of association between dietary adequacy and anthropometry

100

80

20

Total

70

70

0

% > -2SDs

30

10

20

%