Current Information Gaps in Micronutrient Research, Programs and Policy: How Can We Fill Them?

Micronutrient (MN) interventions have a very positive effect on public health and have been a major focus of nutrition research and policy for over 3 decades. Most MN policies are established by the World Health Organization based on available evidence from well-designed trials. These include recommendations on iron + folic acid supplements for pregnancy, high-dose vitamin A supplementation for children <5 years, multiple MN supplementation in young children, food fortification, and universal salt iodization. However, important gaps remain in the evidence base, some periods of the life span have been paid insufficient attention, and some MN policies are incomplete or inconsistent. Examples include the pending decision about whether to recommend multiple MN supplementation in pregnancy or preconception, a lack of information about whether supplementation of lactating women improves breast milk quality and infant development, uncertainty about when and where fortification of complementary foods or supplements is beneficial to preschoolers, and whether folic acid fortification can be harmful in population groups with a high prevalence of vitamin B12 deficiency. The most effective dose of MNs has rarely been tested systematically. MN interventions alone are not very effective for improving the growth and development of young children. Newer methods for the analysis of MNs in breast milk are revealing low concentrations in many populations, so more information is needed on the effects of different interventions on milk nutrient content. We need to improve biomarkers of MN status and should measure multiple biological responses to MN interventions using modern nutritional science methods, including metabolomics, proteomics and epigenetics; these will reveal effects of MNs that are not yet fully appreciated.