Trace elements in starter infant formula: dietary intake and safety assessment

The aim of this study was to investigate the concentrations of five essential (Fe, Mn, Zn, Cu and Se) and four non-essential/toxic elements (Cr, Cd, Ni and Pb) in 35 different starter infant formulas (0-6 months) sold in Italy. In addition, a safety assessment of these trace elements was carried out, by comparing the estimated daily intake (EDI) with the adequate intake (AI) and the provisional tolerable daily intake (PTDI), with a view to provide information on the metal distribution patterns and health risk to infants arising from the consumption of these products. The concentrations were determined by using inductively coupled plasma mass spectrometry after microwave digestion. The concentrations expressed in geometric mean ± geometric standard deviation of Fe (6.17 ± 1.61 mg/L), Zn (6.21 ± 1.31 mg/L), Cu (416.4 ± 1.21 μg/L), Mn (121.5 ± 1.85 μg/L) and Se (13.27 ± 1.67 μg/L) were within legal limits. In spite of this, the mean EDIs of Fe (4.81 mg/day) and Mn (94.75 μg/day) were many times higher than the recommended AI, especially for Mn. Chromium, Ni, Cd and Pb concentrations were not detectable in 11, 37, 57 and 66% of the samples, respectively. Considering the overall sample, the GM ± GSD of these elements were 4.80 ± 5.35 μg/L for Cr, 1.02 ± 11.65 μg/L for Ni, 0.21 ± 14.83 μg/L for Cd and 0.14 ± 17.13 μg/L for Pb. The mean EDIs were far below the respective PTDI. When the safety assessment was based on the 75° percentile level of each elements, all EDIs remained well below the PTDI, with the exception of Cd, whose EDI approached (74.7%), albeit remaining below the PTDI. In conclusion, our results and the increased awareness on the potential risks of excessive Mn and Fe for infants support that an urgent scientific-based definition of the appropriated levels of fortification in formulas is required. Moreover, regular monitoring of all the stages of production of infant formulas is essential in order to limit toxic metal contamination.