key messages anD the way

ForwarD in Dietary assessment

5

5.1 Key messages

• The aim of this resource guide is to support readers in selecting a dietary assessment method for a context specific purpose and to provide information on the principles and practical considerations that are important in the selection process, with a focus on low resource settings.

• This guide was written for professional readers, who have knowledge in nutrition and/or dietetics, and more specifically, dietary assessment. The purpose of creating the manual is to support an informed decision-making process for professionals to select a dietary assessment method and to provide a resource for those who wish to refresh or update their knowledge in the subject. In this way readers could gain a better understanding of the rationale for choosing an appropriate dietary assessment method, prompting them to consider the most relevant questions to guide the selection process, while others are provided with a resource for updating their knowledge and information on the topic of dietary assessment methods, specifically in low resource settings.

• Dietary assessment estimates can be obtained at individual or household levels, and their results can be presented as energy and nutrient adequacy, dietary quality, food patterns, intakes of individual foods and food groups, intakes of macronutrients and micronutrients, and diet composition. These estimates are obtained via direct and indirect retrospective or prospective assessment methods. The information gathered is then used to inform various purposes, including target setting, risk assessment, monitoring and surveillance of food consumption patterns and analysis of diet–disease relationships. The information is also useful for the development of a range of food-based indicators for policy process across governmental departments such as agriculture, health, education, finance, planning, trade, etc.

• The study objectives will guide and determine what needs to be assessed, in what detail, of whom and by whom and what are the determining factors that drive the method selection. Furthermore, the level of accuracy and precision needed for the study can also play a role in guiding the selection process for the most appropriate dietary assessment method to choose.

©FAO/Paballo Thekiso

• It is important to be aware that uncertainties, errors, and the unsuitability of different dietary methods for specific programmatic decisions can lead to inaccurate interpretations of findings, resulting in wasted resources.

When selecting a method, consideration should be given to the study objectives, resources available and characteristics of the study population, i.e. its culture, religion and particularly the cultural food habits.

• It is important to address a number of methodological considerations prior to selecting the most appropriate dietary assessment method which can help to guide the decision making process. These methodological considerations include: the number of days required to estimate intakes;

training needs of the participants; seasonality effects; geographical location; individual, community and culturally-specific issues;

intra-household food distribution; shared eating occasions, street food and eating out habits; estimation of portion sizes and food composition databases.

• It should be noted that all dietary assessment methods need to be tested for their validity and reproducibility in assessing food and nutrient intakes. Furthermore, one should also keep in mind that all the dietary assessment methods are subject to measurement errors, which can be systematic or random. Understanding these and defining strategies to address sources of error could result in better estimates and measurements.

• While the integration of advanced innovative technologies – i.e. smartphones, mobile applications, software, sensor-based recording – to improve dietary assessment has shown progress in developed countries, their usage in low resource settings and in low literacy populations is still limited. Nevertheless, technologies such as digital photographs

have been successfully used in low resource settings; researchers in developing countries should be encouraged to investigate these technologies further.

• Proxy tools such as dietary diversity scores are useful in low resource settings due to their simplicity and low cost. Nevertheless, they need to be adapted to the local context and the specific characteristics of the population, prior to their application. It should also be noted that they are not suitable methods for assessing individual-based and/or quantitative dietary intakes.

• One of the few available reviews on the application of dietary assessment methods in programmatic decisions concluded that none of the methods reviewed could be considered a “gold standard”; some are better suited to particular contexts than others; the validity and usefulness of a method for a given purpose should guide its selection (taking into consideration sources of potential bias and error); and that simple informed modifications to data collection and processes can improve their usability in programmes.

• When using this guide, users should remember that dietary assessment is one of the four nutrition assessment components, the others being anthropometry, biomarkers and clinical assessment. These other complementary methods should not be overlooked when planning an assessment but are outside the scope of this manual to expand upon further. Equally crucial to nutrition-related programmes is the assessment of food intake practices, knowledge, and beliefs. (Note that these are likely to be of greater importance within the context of developing countries than developed countries.) No description of the assessment of these practices is provided here, but readers interested in this topic are directed to the FAO Guidelines for assessing

nutrition-related Knowledge, Attitudes and Practices²³.

5.2 the way forward

• The need for such a resource guide is reflected in global economic developments and changing patterns across the food chain, which necessarily entail a corollary impact on individuals’ diets and population health.

The information presented complements ongoing work in FAO’s Nutrition and Food Systems Division that supports global efforts to strengthen national nutrition information systems vis-à-vis monitoring and implementation processes. Examples of such work include the FAO/WHO Global Individual Food Consumption Data Tool (FAO/WHO GIFT), which aims “to collect, harmonize, and disseminate data available at national and sub-national level all over the world through an FAO hosted web-platform”²⁴. This platform, intended for use by both experts and a broader audience, aims to facilitate access to microdata and to compute food-based indicators – such as average leafy vegetable consumption, main food sources of vitamin A or high levels of fish consumption – so that data is comparable between different population groups and geographical areas.

• Moving on from ICN2 to the post-2015 sustainable development agenda requires coordinated and synchronized efforts in dietary assessment. Countries can learn valuable lessons from each other’s experiences; quite often the international community raises such issues, including calls for stronger national mechanisms for monitoring and evaluation of a population’s nutrition. When resources are available and infrastructure is in place,

monitoring and evaluation of a population’s diet is relatively straightforward. Within such contexts, opportunities exist or arise to improve individual-based methods, understand their errors better and their influences on data interpretation. However, when resources, capacity and infrastructure are not sufficient or are non-existent, professionals may want to make use of the existing nutrition information structures already in place. An example is using the HCES as a secondary source of data to inform policies with recent calls for improving their relevance and reliability in nutrition policy-making.

23 http://www.fao.org/docrep/019/i3545e/i3545e00.htm

24 http://www.fao.org/nutrition/assessment/food-consumption-database/en/