Micronutrient deficiencies affect 1 in 3 persons globally and contribute to disease and lost productivity. Large-scale food fortification (LSFF) is a widely used strategy to address micronutrient deficiencies by adding micronutrients to staple foods at the point of processing. Laws requiring LSFF fortification exist in:
- 126 countries for salt,
- 35 countries for oil,
- 8 countries for rice,
- 92 countries for wheat flour, and
- 19 countries for maize flour
Figure 1. Mandatory and voluntary fortification legislation by food vehicle type. Source: Global Fortification Data Exchange Interactive Maps on Fortification Legislation, accessed February 23, 2024. Green, blue, and tan shading indicate mandatory, voluntary, and unknown in terms of fortification laws for each food vehicle. [https://fortificationdata.org/interactive-map-fortification-legislation/]
For LSFF to have a public health impact, high-quality fortified foods must reach and be consumed by vulnerable populations. Accurate and timely data on the proportion of the population that consume fortified foods can help track progress and guide necessary actions to improve coverage of LSFF programs. However, there are major global gaps in data on fortification coverage for most foods except salt.
The measurement challenge: quantifying the invisible
LSFF coverage can be challenging to measure because it is often “invisible” to beneficiaries. Consumers may not know if they have purchased or consumed fortified foods. In most cases, fortification does not alter the taste or appearance of food. Asking a household survey respondent if they consume fortified foods may give you an uncertain answer.
Supply-side approaches can be used to indirectly estimate coverage, indicating whether fortified foods are available for sale or being distributed through programs. Government or industry data monitoring compliance with specified standards for the amount and type of added micronutrients is routinely collected in many settings; however, these data are not typically publicly available.
Coverage is best measured at the beneficiary level and should ideally reflect actual consumption of fortified foods. It would be ideal if surveyors could rapidly test for the presence of added micronutrients in food samples during a household visit. A rapid test kit has been available to test iodine in salt for many years. However, such testing is not yet routinely done for other fortified food vehicles due to high cost and technological barriers associated with measuring multiple micronutrients.
Existing methods for fortification coverage measurement
In the absence of cost-effective field-friendly rapid tests, a combination of data sources must be used to identify: 1) the type and brand of food consumed by the household or individual; and 2) fortification status of the food (i.e., presence of added micronutrients or not). The purpose is to link individual or household data on reported consumption to fortification status data from households or other sources.
This approach is used in the Fortification Assessment Coverage Toolkit (FACT) survey, developed by the Global Alliance for Improved Nutrition (GAIN) in 2013. In the last decade, more than 20 FACT surveys have been conducted in over 15 countries.
The FACT method collects data at the household level and, in some cases at the market level, to generate three coverage indicators (Figure 2):
- Indicator 1: Proportion of households that consume a food vehicle (e.g. any type of oil)
- Indicator 2: Proportion of households that consume a fortifiable food vehicle (e.g. oil which is industrially processed and amenable to adding micronutrients)
- Indicator 3: Proportion of households that consume a fortified food vehicle (e.g. oil that is confirmed to contain added vitamin A based on vitamin A measurement of samples of oil products)
All indicators can be generated from household data alone; however, indicator 3 requires the collection and analysis of food samples. Given the high cost to collect and analyze food samples at the household level, this type of data is not always possible to collect. As an alternative, data on the fortification status of foods from other sources, such as a market or production level assessment, can be linked to household data to generate this indicator. To link these datasets, information on the specific type and brand of the food vehicle consumed by the household is used. In practice, this linkage has proven to be challenging in contexts where foods are often procured in unbranded form and/or the respondent has insufficient recall of the brand.
Figure 2. Fortification coverage indicators, using oil as an example
1Data on fortificant levels can be collected from various sources (household, market, production)
The measurement opportunity: refining LSFF coverage measurement through household surveys
FACT coverage indicators have been integrated into large-scale household surveys such as the national Performance Monitoring and Accountability 2020 (PMA2020) surveys in Kenya and Burkina Faso conducted in 2018. A parsimonious set of refined LSFF coverage questions could be added as core or optional modules in other large-scale household surveys such as the Demographic and Health Surveys (DHS), Multiple Indicator Cluster Surveys (MICS), Living Standards Measurement Surveys (LSMS), and other national nutrition surveys.
In the lead up to the DHS-8 revision process in September 2018, DataDENT facilitated a two-day technical consultation on Measuring Nutrition in Population-Based Household Surveys and Associated Facility Assessments. Participants included donors (Bill & Melinda Gates Foundation and USAID) UN agencies (UNICEF and WHO), GAIN, and national stakeholders. Participants endorsed a recommendation to add a set of questions to generate coverage indicators 1 and 2 for oil, wheat flour, and salt to the DHS-8 questionnaire. The questions were not ultimately adopted by the DHS Program (except for a modification of the pre-existing question for salt iodization), but the convening raised global tracking of LSFF coverage through large-scale household surveys as a priority amongst the nutrition community.
DataDENT is currently working in collaboration with GAIN to test and refine the minimum set of questions needed to generate the FACT coverage indicators, as part of formative research in Bangladesh and Ethiopia. The questionnaire will include more detailed response options to better understand what type and brand of food and where the household procured it. Each question in the FACT fortification coverage module will undergo intensive cognitive testing to identify question elements that are more likely to produce cognitive errors related to question comprehension, retrieval, judgement, and response. We will also validate respondent recall of the type and brand of food they last purchased through direct observation in the home. These questions will then be piloted in a household survey in Bangladesh in late 2024. DataDENT will share lessons, findings, and guidance to support uptake of the questions in the upcoming DHS-9 process and other global and national survey programs.
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