Meat as an early complementary food for infants: implications for macro- and micronutrient intakes.

Optimal complementary feeding is recognized to be critical for prevention of infectious morbidity and mortality and for optimal growth and development. The nutrients which become limiting in human milk after approximately 6 months of exclusive breastfeeding are predictable based on the dynamic composition of human milk and the physiology of infant nutritional requirements. Iron and zinc are two micronutrients for which the concentrations in human milk are relatively independent of maternal intake, and for which the older infant is most dependent on complementary foods to meet requirements. Traditional feeding practices, including reliance on cereals and plant-based diets, do not complement these recognized gaps in human milk. Meats or cellular animal proteins are richer sources of these critical minerals as well as other essential nutrients. Yet, cellular animal proteins are often introduced only late in infancy in developed countries, and may be only rarely consumed by young children in developing countries. Plant-based diets result in a predominance of energy from carbohydrates, often including highly refined carbohydrates that are also likely to have a high glycemic index. This pattern of macronutrient intake is contrary to that of the period when the human genome evolved, and may influence the metabolic profile in young children, especially under conditions of nutritional abundance.