Comparison of breast milk and infant formulas in essential and toxic elements content

Background and aim: Human milk is considered to be the best source of nutrition for the newborn infants, and exclusive breastfeeding is recommended by WHO up to 6 months of age. It contains all the nutrients and essential trace elements necessary to ensure correct functioning of the organism. Sometimes, breast milk may be a potential source of undesirable (toxic) elements as their content reflects the level of environmental pollution and mother’s diet. In developed countries, the most common substitutes for human milk are commercially available infant formulas. Nutrient levels in formulas are generally modeled on the composition of human milk with the aim to make them similar. Relatively few recent data on breast milk which can be used as background data for setting adequate daily intakes for infants, are available from women living in Italy. The aim of this study was to determine the levels of five essential (Fe, Zn, Cu, Mn, Se, Cr) and four non-essential/toxic elements (Ni, Cr, Cd, Pb) in breast milk of women living in Modena, Italy; to compare them with recommended values; to investigate the relationship with diet and mother characteristics; to compare them with infant formulas. Methods: 130 samples of human milk (mature milk: 30-40 days postpartum) and a representative sample of infant formulas (0–6 months) sold in Italy were analyzed by ICP-MS in triplicate after microwave digestion. Results: Mature breast milk contains adequate levels of essential trace elements, despite the inter-individual variability not influenced by the women characteristics, demographic parameters and dietary habits. Non-essential/toxic elements content was well below the maximum tolerable limits set by EFSA. Regarding infant formulas, higher amounts of Fe and Mn were observed in comparison to breast milk. Conclusions: This study highlights that the levels of essential micronutrient in lactating women living in Modena are suitable for the proper development of infants and no risk for excessive toxic elements intake was detected. Comparison with infant formulas shows that high fortification with Fe and Mn requires more attention by researcher and international authorities. According to our findings, breastfeeding should be still encouraged and recommended.