Micronutrient research, programs, and policy: From meta-analyses to metabolomics.

Micronutrient deficiencies are widespread among women and children in undernourished populations. Research has identified effective approaches to their prevention, including supplementation, fortification, and dietary and other public health interventions. These interventions have made tremendous improvements in the quality of life, health, and survival of populations around the world, yet the impact varies by nutrient, population, and the outcomes chosen that reflect nutritionally driven change. The WHO guides governments and agencies toward effective strategies to prevent micronutrient deficiencies in women and children, but these are often informed by imperfect studies with limited measures of impact and the inadequate program evaluations and survey databases produced by the nutrition community. The resulting knowledge gaps limit our ability to discern what interventions are effective, under what conditions, among whom, and perhaps most important, why. However, we are moving into an era of opportunity to apply the tools of modern nutrition science, including improved methods of assessing nutritional status, "omics," bioarchival access, systems biology thinking, and interdisciplinary collaborations, that can deepen and broaden our understanding of how micronutrients affect health, how their deficiencies diminish human capacity, and how interventions can improve the well-being of those in need. Relevant training and greater cross-disciplinary efforts will be required to ensure a cell-to-society approach that can systematically address where, to whom, and how to provide micronutrients in the future.