The benefits of animal products for child nutrition in developing countries.

One in five children across the globe experience stunted growth and underdevelopment due to malnutrition. Animal-source foods (ASFs) offer the opportunity to address this problem and make significant progress towards achieving the World Health Assembly nutrition targets. Eggs and milk are among nature's first foods, providing holistic packages of nutrients and bioactive factors to support healthy growth. They are also affordable and accessible to lowresource, vulnerable populations. Biological and evolutionary rationale argues for the use of ASFs during the complementary feeding period when children are most at risk from infectious diseases and malnutrition. Dietary patterns in the evolutionary history of hominids point to the importance of ASFs for increased brain size and function. Studies also demonstrate high bioavailability of limiting nutrients, such as vitamin A, iron, zinc and fatty acids in the ASF matrix, ensuring efficient absorption and metabolism. The empirical evidence for intervention using eggs, milk and fish, however, remains somewhat limited. One recent trial in Ecuador, the Lulun Project, demonstrated that one egg per day for six months, beginning early in complementary feeding, produced a large effect on linear growth and reduced stunting risk by 47%. To sustainably build systems that support equitable and adequate ASFs in the diets of all children globally, consideration should be given to microeconomic and macroeconomic factors, 'One Health', and maintaining balance in the ecosystem. Important contributions may then be achieved through ASFs for the well-being of populations worldwide.