Exploring the Nutritional Ecology of Stunting: New Approaches to an Old Problem.

Despite a declining prevalence, stunting remains an elusive target for the global health community. The perception is that stunting represents chronic undernutrition (i.e., due to inadequate nutrient intake associated with food insecurity, low-quality diet, and suboptimal infant feeding practices in the first two years of life). However, other causes include maternal-fetal interactions leading to intrauterine growth retardation, poor maternal nutrition during pregnancy and lactation, and maternal and pediatric infections. Moreover, physical, economic, demographic, and social environments are major contributors to both food insecurity and conditions that limit linear growth. Overall, factors representing both the internal and external "nutritional ecologies" need to be considered in efforts to reduce stunting rates. Nutritional assessment requires better understanding of the mechanism and role of nutrition in growth, clear expectations about the sensitivity and specificity of the tools used, and inclusion of bio-indicators reflecting the extent and nature of the functional effect of poor nutrition and environmental factors contributing to human physical growth. We provide a perspective on current knowledge about: (i) the biology and contribution of nutrition to stunting/poor growth; (ii) our current nutritional assessment toolkit; (iii) the implications of current assessment approaches for clinical care and public interventions; and (iv) future directions for addressing these challenges in a changing global health environment.