TRACE ELEMENTS IN INFANT MILK

Introduction: When breast feeding is not possible, infant formulas are often used as substitutes for human milk and play an indispensable role in infant nutrition. These substitutes are specially manufactured and fortified with micronutrients such as vitamin, trace and mineral elements, essential to satisfy the nutritional requirements of infant. Although trace elements play an important role in infants’ growth and development, their amount in formula composition has received very little attention, since recent research on such food has focused mainly on protein and energy content. We aimed to determine the levels of various essential (Fe, Zn, Cu, Mn, Se, Cr) and toxic (Cd, Pb) elements in a representative sample of infant starting (0-6 months) formulas consumed in Italy, in order to increase the knowledge on infant exposure to trace elements and to compare the results with standard recommended values. Formula milk concentrations of the investigated elements were also compared with those obtained in a sample of mother’s milk. Materials and methods: The mineral content of the commercially available milk-based infant formulas consumed in Italy together with 5 human milk samples were investigated. We included starting infant cow’s milk, powder and liquid formulas and we excluded products not officially on sale in Italy. Dry powder milk samples were reconstituted according to the manufacturer's instructions, using distilled water to avoid any external contamination. The levels of elements were determined by ICP-MS after microwave digestion. For the precision and accuracy of the method, a standard reference material (BCR 063R: whole milk powder) was analyzed. Results: The levels of essential elements were within min/max of recommended values established by European directives. Fe, Zn and Mn were significantly higher in all investigated formulas than in breast milk. Particularly, concentrations of Mn from formula varied from 15 up to 40 times the concentration of breast milk. Concentrations of Pb and Cd were detected in some infant formulas, although none in amounts that could represent a health hazard for the consumer, while they were not detected in human milk. Conclusion: The results of this study highlight two important aspects: the presence in infants formulas, although at low levels, of toxic elements such as lead and cadmium, which in our opinion should be absent in food products, and the excessive fortification of essential elements such as Fe, Zn, Mn in infant formulas in comparison to breast milk. Growing evidence of negative effects on cognitive development from excessive Fe and Mn intake suggests, in line with other researchers, a deep consideration on the real need to fortify commercial human-milk substitutes to such high concentrations, since infants are characterized by higher absorption and less effective excretion of dietary elements compared to adults