Micronutrient adequacy of diets and contributions of large-scale interventions: secondary analyses of household surveys

Despite advancements in several micronutrient innovations to improve diet quality, addressing population micronutrient needs with interventions that can reach target groups with the right micronutrients in adequate quantities is challenging. A dearth in dietary intake data to identify needs and measure the impact of micronutrient interventions, especially in sub-Saharan Africa, currently limits the design of effective micronutrient policies and programmes. Household survey systems generate a particular kind of dietary data and exist in most countries, but understanding how to assess diets and model micronutrient contributions from interventions using these data remains undefined. This thesis explores the uses of existing national household survey systems to assess the micronutrient adequacy of current diets and the potential contributions that large micronutrient programmes can have to meet needs. First, a description of data sources and a systematic literature review identified the kinds of dietary micronutrient metrics used from Household Consumption and Expenditure Surveys (HCES) and comparability to other dietary assessment methods. A secondary data analysis was then conducted to conceptualise how different metrics can be used together to characterise vulnerable populations. Based on this, a model was then built using data from Malawi to understand the potential contributions of large-scale food fortification to meet micronutrient needs. Finally, an additional secondary data analysis explored whether information gaps from other relevant micronutrient interventions could be filled using data from other household surveys. These results demonstrate that household survey systems hold unexploited potential when generating evidence to help inform micronutrient policies and programmes, despite data limitations and heterogeneity between survey systems. These information, when interpreted appropriately, can help identify micronutrient needs for vulnerable populations and geographies and are useful for targeting monitoring efforts and guiding resource distribution. Recent investments have galvanised interest in leveraging existing data systems to understand impacts from micronutrient interventions, but additional investments in primary data collection should focus on vulnerable population poorly represented by household surveys. This thesis presents a method to answer two fundamental questions when designing micronutrient policies and programmes: who has the greatest unmet micronutrient needs and how can these needs be met through public policy and programmes? Future research refining these methods in other countries and for other micronutrient interventions would further strengthen this body of evidence. New primary data investments are also necessary to fill micronutrient data gaps that are present in current household survey systems.