Define indirect method of dietary assessment?

Indirect method of dietary assessment

Introduction;

Estimation of nutrient of food intake/diet pattern of an individual or all the individuals of a household/ population over a specific time period is termed as dietary assessment'' dietary assessment is one of the four major approaches employed for comprehensive assessment of nutritional status.

The nation famous from the ancient time stating that'' diet and health are interlinked'' is the major focus of medical practitioners these days.

Discovery of the protective role of citrus fruit against scurvy among sailors formed the historical perspectives of this nation and suggested a need to find relationship among diets and diseases.

However, diet has a vital role in etiology and also helps to prevent several chronic diseases such as cardiovascular disease, cancer, hypertension and diabetes. Moreover, our genetic disposition is effected by eating habits as well as lifestyle factor such as smoking and physical activities.

Assessment of the health outcomes of dietary habits has become pivotal due to recent health behavior and complexity of nutrition, It' s quite a tough task to record the food consumption or eating habits of people. Even there are chance of errors; the best available method are being used either in combination or individually for nutritional assessment.

Adequate assessment of dietary intake has its importance not only in establishing the relation between diet and health but also in evaluating patient' s nutritional status in clinical setting'

Dietary assessment is concerned not only with the amount and types of foods consumed but also with the nutritional components present in these foods.

Thus, estimates of nutrient intake can be obtained by combining food consumption data with the nutrient composition data of those food. These are several methods available to collect food consumption data however, not even a single errorless method has yet been discovered for diet measurements.

Every method has benefit and drawbacks of its own. Despite of the fact that every method has certain disadvantages associated with it, even then the approximately collected dietary data have considerable value. Accurate use of assessment method and suitable data analysis technique can represent a clear relationship between the diet and disease.

However, occasionally inappropriate use of these techniques can lead to the wrong calculations hiding diet-disease relationship. Important considerations while choosing the method for dietary assessment include, available resources, characteristics of the study participants, and the research design.

Indirect Methods:

In indirect methods , secondary information (e.g. agriculture statistics, food supply, food expenditure) is used to make the estimation of food available for consumption at the national as well as household levels.

First of all, food balance sheet(FBS) will be looked, which gives information on food consumption at the national level: estimation of food consumption is made from the food supply ' s point of view.

Household consumption and expenditure surveys HCES:

Household food consumption is usually defines as food surveys to test significant part of family financial condition including food obtaining and utilization. This kind of surveys are usually practiced in several countries to make a check on household living conditions, poverty status and income distribution. Following are some of common method used to assess food consumption at household levels.

a. Food account method FAM:

It involves collection of daily records of food purchased, received as gifts or grown at home for household use over specific time period. Food quantities are recorded using household tools or in retail unit. Brand name and prices of food are also mentioned.

This method does not include the food and beverages consumed outside the home, food discarded as wastes or fed to animals.

b. Household food record method:

Complete records of food consumption of at least one week can be recorded either by a household member or by the surveyor himself. This methods record information of the food actually eaten in comparison to FAM which only keeps track of foods procured.

During the survey, period of one week, the actual weight and volume of each meal is recorded before serving to each household individual.

Record comprises complete details including brand name and cooking methods. Weight and volume of each ingredient and and weight of cooked dish is also recorded.

Sometime, food waste in individual plates is weighed after each meal but generally waste food and food fed to animal is not accounted. Instead, a waste factor of 10% on all edible food consumed is applied.

c. Household 24-hour recall method:

The member of the household responsible for handling and preparation of food is interviewed in this method to get information related to household composition and the food consumed in last 24 hour.

Application of HCES:

Data obtained from HCES can be used to launch food fortification programs to alleviate micronutrient deficiencies.

HCES helps in gauging the food security situation in different regions within country.

HCES data helps to assess household dietary intake, particularly, in estimation of micronutrient intake can be used to indicate population at risk of micronutrient deficiencies.

More reliable in tracking diet pattern in comparison to individualized assessment approaches.

Provide substantial evidences of the external influences affecting the access to food and its consumption.

Accuracy of HCES:

Accuracy of HCES varies according to the methodology used to conduct survey. Moreover, it depends upon ability of respondent to present the requisite information such as amount of food purchased, prepare and consume during survey period.

The householder might remember the food items recently purchased but the major concern of HCFSs is with the reporting of actual food consumption taking into account the leftover of pervious purchase, grown in home or consumed outside of the house.

Accuracy of questionnaire based GCFSs depends primarily on the quality of question and length of the questionnaires. Nutrient consumption might be underestimated if any of the nutrient sources and raw ingredients used for the preparation of food is not reported.

Lack of information regarding food procurement and intra household food exchanges variation limit the validity of household distribution can be made based on the energy requirement of the individual but errors are likely to occur.

HCESs are less precise when individual data is required, however, low cost rather than always remain an attractive tool for policy makers to identify the vulnerable populations.

Strengths

1)Inexpensive method for collection of nutrition data since household surveys are conducted for collection of demographic and health indicators

2) Accessible to all and relatively simply to analyze the information if questionnaire are appropriately designed

3) Represent the socioeconomic and demographic characteristics of the head of the households. HCESs are also important to identify he dietary trends in different regions with in a country and identify the areas where nutrition intervention should be launched

4) HCESs data enable to examine the changes in dietary pattern depending upon food availability and consumption at national level

5)HCESs are statistically representative at both national and subnational levels

6)Contain comprehensive information related to household food consumption reflecting the invaluable importance of agriculture and nutrition in growth of the nation via markets, value chains and associated pathways.

Limitations;

Data might not be essentially considered representative due to lack of ability to recall. Training of surveyors and well-designed questionnaires can help to minimize this limitation.

Non-standardized units are likely to be used by the householders to record food quantity.

Foods discarded are wastes and fed to animal is not accounted hence, consumption can be over-estimated.

Foods eaten outside the home are not often accounted.

If the food list used in the questionnaire does not contain all food options, misrecording/misreporting can occur.

Individual involved in eating a meal might be different from the actual number of household.

Does not give information about individual food consumption and food distribution within a household.