The role of livestock products for nutrition in the first 1,000 days of life

Dietary patterns across the world are extremely diverse, with diets of most people in low- and middle-income countries being suboptimal from a nutritional standpoint. It is in these countries that the highest levels of undernutrition are recorded, with children being the most affected. Although stunting (i.e., children short for their age) rates are declining globally and regionally, significant disparities in such rates exist between and within countries. Moreover, the absolute number of stunted children in Africa continues to increase (Development Initiatives, 2018). Iron-deficient anemia has risen to 32.8% globally and nutrient intakes are typically deficient in poor settings. Poor people in poor countries often subsist on suboptimal diets based on cheap staples and have limited access to nutrient-dense foods such as pulses, fruit, or meat (Murphy and Allen, 2003; Thompson and Meerman, 2010; Muhihi et al., 2012). As a result of these circumstances, individuals do not receive sufficient nutrient intakes to sustain optimal well-being. Some research has shown that it is not unusual to begin feeding children livestock-derived food (particularly milk) before 6 mo of age when they should be exclusively breastfeeding (Micere et al., 2016). With that said, recent surveys confirmed that almost 40% of children above 6 mo living in informal settlements in peri-urban Nairobi did not consume cow’s milk daily. Furthermore, meat and other livestock-derived products were each eaten by less than 5% of these children and only in very small amounts (Grace et al., 2018). This is not an uncommon reality in Africa. Over the past decades, investments have been made to address the various forms of undernutrition present in many countries across the world. The shift from food security (access to enough food) to nutrition security (access to enough nutritious food) has prompted the development of interventions to increase nutrient intake. These interventions include food fortification as a means to improving the nutrient content of diets. Little attention has been given, however, to the specific role of livestock products such as meat, milk, and eggs (and their derived products) on nutrition and their potential to help achieve nutrition security goals. Media outlets in recent years, primarily in high-income countries, have increasingly been flooded with reports that are critical of the role of meat, in particular, and livestock-derived foods (e.g., milk and eggs), in general, as part of diets. Their environmental footprint, as well as their suggested negative effects on health, are ostensible arguments used to promote a shift to diets containing little to no animal-sourced foods. Environmental and sustainability concerns exist related to livestock production that require serious reflection relative to the evolution of farming systems and dietary patterns in industrialized countries (Willett et al., 2019). Underlying this may be more fundamental and immutable concerns over the use of animals (Perry and Grace, 2015). Nonetheless, in many low- and middle-income countries, the livestock sector is a key contributor to national economies (representing between 15% and 80% of agricultural domestic product) and represents a potential pathway out of poverty and an essential livelihood for millions of people (World Economic Forum, 2019). In countries where high volumes of livestock production accompany important undernutrition problems, it would represent a significant missed opportunity to not harvest livestock-derived food products to optimize the nutrition of the most vulnerable. This article will summarize the current state of knowledge on the role of livestock products for nutrition, with emphasis on the first 1,000 d of life for individuals living in low-income countries. The nutritional importance of livestock products, the evidence base for their impact on health and nutrition, and the major externalities concerned with their production will be considered