Food Based Complementary Feeding Strategies for Breastfed Infants: What's the Evidence that it Matters?

The period of complementary feeding represents a major portion of the 1000 day critical window and thus impacts a period of substantial and dynamic infant development. This review highlights and synthesizes findings of several recent studies conducted to evaluate food based strategies on outcomes related to micronutrient status, growth and neurocognitive development. Particular emphasis is placed on interventions using meat or fortified products to impact iron and zinc intakes, due to the dependence of breastfed infants on complementary food choices to meet requirements for these two critical micronutrients. Regular consumption of modest amounts of meat or fortified cereals provides adequate absorbed zinc to meet estimated physiologic requirements, whereas homeostatic adaptation to lower zinc intake from unfortified cereal/plant staples is inadequate to meet requirements. Iron fortification of cereals may be somewhat more effective than meat to improve iron status, but neither prevents iron deficiency in breastfed infants, even in westernized settings. Improvements in the quality of complementary foods have had very modest effects on linear growth in settings where stunting is prevalent. Maternal education is strongly associated with both linear growth and with child neurodevelopment. The determinants of early growth faltering are more complex and intractable than 'simple' dietary deficiencies of micronutrients. Solutions to growth faltering in young children most likely need to be multi-factorial, and almost certainly will need to start earlier than the complementary feeding period.