Micronutrients in Human Milk: A Global Perspective

Given the importance of breast milk for providing micronutrients (MN) in the first 6‐24 mo our objective is to determine if its MN content is adequate in populations with poor dietary quality and how it is affected by maternal supplementation. We developed methods, including HPLC‐MS/MS, to analyze multiple MN simultaneously in the milk matrix improving accuracy and efficiency of older methods. Available samples collected at 2‐4 mo lactation were identified from multiple countries. Average population concentrations were expressed as % of those accepted by the IOM when setting DRIs for infants and lactation. Examples of the large differences in composition include: B1, 60% in India; riboflavin, 70% India, 30% Malawi, 20% Philippines and 10% in Bangladesh; niacin, 10‐20% (including California); B6, 220% California, 80% India, Malawi and Bangladesh, and 20% Philippines; B12, 60% Malawi, 30% India, and a very low 20% in Guatemala. Supplementation of HIV+ women in Malawi with 1X RDA from 0‐6 mo of lactation increased milk B2, niacin, B6 and B12 by 30% within weeks, but had no effect on B1. ARV treatment eliminated these positive effects of supplementation. We also identified acute effects of MN supplements revealing that time of collection can substantially over‐ or under‐estimate true effects a dose of MN at 1X RDA in Bangladeshi women at 2 mo postpartum increased 24 h secretion of B1 by 10%, B2 by 75%, niacin by 25%, B6 by 96%, but B12 0%. This effect within hours of the supplement. Thus vitamin concentrations vary greatly across populations demonstrating need to evaluate benefits of MN supplements in lactation for mothers and infants, and further evaluate accuracy of estimated nutrient requirements in infancy and lactation. (Bill & Melinda Gates Foundation & USDA, ARS).