Human Milk as the First Source of Micronutrients

Well-nourished mothers are assumed to produce adequate concentrations of nutrients in their milk for optimal infant growth and development and infants should be exclusively breastfed during the first 6 months. It is important to know the nutrient content of human milk as this information is used to set recommended adequate intakes (AIs) for infants. Our review of existing information reveals that the AI recommendations are based on poor data. The milk content of a few nutrients may not be adequate to provide requirements for 6 months even in well-nourished mothers. Importantly, the concentrations of many micronutrients in milk are low when the mother consumes a poor quality diet. Our new efficient methods for milk nutrient analysis have enabled us to illuminate the large differences in milk micronutrient concentrations across populations, to examine the effects of milk collection protocols on nutrient concentrations, and to study the effects of maternal supplementation in pregnancy and/or lactation on milk micronutrient and infant status. The ongoing Mothers, Infants and Lactation Quality study proposes to answer some of these uncertainties. Two hundred and fifty healthy, well-nourished, unsupplemented mother-infant dyads in each of the 4 countries are being studied. The range of milk nutrient concentrations across the first 9 months postpartum will provide "Reference Values" against which other studies and surveys can evaluate the quality of milk and possibly target nutrients for treatment with supplements or fortification.