Using dietary reference values to define fortification levels for national programs

Authors: Allen, Lindsay - A

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 12/20/2017
Publication Date: 6/20/2018
Citation: Allen, L.H. 2018. Using dietary reference values to define fortification levels for national programs. Book Chapter. 43-50. https://doi.org/10.1016/B978-0-12-802861-2.00004-3.
DOI: https://doi.org/10.1016/B978-0-12-802861-2.00004-3

Interpretive Summary: The purpose of fortifying staple foods with nutrients is to fill the gaps between nutrient intakes and nutrient requirements. The decision to fortify should be based on evidence of inadequate intakes, supported when possible by biochemical or clinical evidence of poor status. The correct way to calculate whether nutrient intakes are adequate is to measure usual food intake and convert this to nutrient intakes for each of the population groups of concern. The intake of each nutrient is then compared to the Average Requirement (AR) for groups of individuals, and the prevalence of inadequacy is calculated as the percent of the group consuming less than the AR. In addition food intake data provides information on the amounts of potentially fortifiable foods consumed, and computer software is available to simulate the effects of different levels of fortification of those foods on the prevalence of inadequate intakes. In addition to the AR, the other important dietary reference value is the Upper Level (UL) of intake, which is used to estimate the prevalence of potentially excessive intakes as a result of fortification. Since measurement of the food and nutrient intake of individuals is sometimes not possible, another approach is to use household food consumption data, for example, and estimate how much fortificant nutrient should be added to a food staple based on past experience of the effects of different levels of fortification. Software is available to perform the calculations necessary to plan fortification levels for both macro- and micronutrients, once nutrient intake data have been collected. It provides ARs and ULs, uses estimates of the percent absorption of the fortified nutrient from the local diet, and based on the distribution of intakes of foods that could be usefully fortified (fortification vehicles), simulates the effect of a range of fortification levels on the percent of people who would have inadequate and excessive intakes in each population group.

Technical Abstract: Fortification of staple foods is intended to fill the gaps between nutrient intakes and nutrient requirements, and should be based on evidence of inadequate intakes, supported where appropriate by biochemical or clinical evidence of poor status. The correct approach is to measure usual food intake and convert this to nutrient intakes for each of the population groups of concern, such as women of reproductive age, or children. The distribution of the intake of each nutrient is then compared to the Average Requirement (AR) for groups of individuals in the population, and the prevalence of inadequate intakes is calculated as the percent of the group consuming less than the AR. Using data on the amounts of potentially fortifiable foods consumed by each population group it is possible to simulate What the prevalence of inadequate intakes would be if one or more of those foods was fortified with various levels of a nutrient. In addition to the AR, the other important dietary reference value is the Upper Level (UL) of intake, which should not be exceeded in any group of the population as a result of fortification. Since measurement of the food and nutrient intake of individuals may be impractical in some situations, alternative approaches have used household consumption data, for example, based on experience with different levels of fortification. Software is available to perform the calculations necessary to plan fortification levels for both macro- and micronutrients, once nutrient intake data have been collected. It provides ARs and ULs, uses bioavailability estimates appropriate for the local diet, and based on the distribution of intakes of foods that could serve as fortification vehicles, simulates what effects fortifying with different amounts of nutrients would have on the percent inadequate and excessive intakes in each population group.