Location: Obesity and Metabolism ResearchTitle: Limitations of the evidence base used to set recommended nutrient intakes for infants and lactating women.
Submitted to: Advances in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2017
Publication Date: N/A
Interpretive Summary: The adequacy of the available data used to set most of the recommended micronutrient intakes for infants and lactating women is reviewed. Values were obtained for milk micronutrient concentrations accepted by agencies in the USA and Canada, FAO/WHO, the U.K., and the European Food Standards Authority (EFSA). These values were accompanied by details of the source of the information, and the number, location, status and stage of lactation of the sample populations, where known. This extensive review revealed that most of the values were derived from a small number of women, longitudinal data during lactation were rare, there was large variability between studies in many cases, and collection methods and status of the mother were often unclear. The review also summarized milk micronutrient concentrations reported in studies where mothers and/or infants were known to be deficient based on clinical symptoms or biomarkers of deficiency; the purpose was to illustrate how low milk values can fall with deficiencies of specific nutrients. We concluded that a new, multicenter study is needed to establish Reference Values for milk micronutrients in well-nourished, but un-supplemented, women across lactation.
Technical Abstract: Reported values for the concentrations of micronutrients in human milk form the basis of the majority of micronutrient intake recommendations for infants and the additional maternal requirements for lactation. The infant recommendations may also be extrapolated to provide estimates for young children. The purpose of this article is to evaluate the adequacy of the milk micronutrient concentration data used by the Institute of Medicine to set recommendations for the USA and Canada, by FAO/WHO, the United Kingdom, and the European Food Standards Authority (EFSA). The concentrations accepted by each agency are presented for each micronutrient accompanied by the source of information and comments on the number, location, status and stage of lactation of the sample population, where known. These summaries demonstrate the small number of participants from which samples were collected in most studies, the wide range of concentrations within studies, the lack of longitudinal data, and variability in collection methods. These factors contribute to the variability in nutrient intake recommendations among committees, although this variability is reduced by some committees accepting milk composition values proposed by others. Values are also summarized from milk collected in studies where mothers or infants were known to be deficient, based on clinical symptoms and/or biomarkers of inadequacy, to illustrate the extent to which milk micronutrients can be reduced by poor maternal nutritional status. We conclude that a new, multi-center study is needed to establish reference values for milk constituents across lactation.