Chromium content in different kinds of Spanish infant formulae and estimation of dietary intake by infants fed on reconstituted powder formulae

Abstract

Chromium is well documented as an essential element for humans. Trivalent chromium, the main chemical form found in foods, is essential for maintaining normal glucose metabolism. Owing to analytical difficulties, several literature reports of chromium content of foods, especially for the lower levels, show large variability and should be interpreted with caution. Zeeman background correction, transversely heated graphite furnace atomic absorption spectrometry was used to determine the chromium content of 104 different infant formulae (cow's milk and soy protein based) marketed in Spain following an acid-digestion sample preparation procedure in a closed, pressurized and microwave digestion unit. The mean and range of chromium values, regarding types and main protein-based infant formulae are presented. Additionally, the influence of the type of container used, the impact of industrial process from different manufacturers and the physical state (powder and liquid formulae) on chromium levels is also discussed. In general, the infant formulae contain a higher chromium concentration than that found in human milk (reference range: 0.20–8.18 µg l−1), particularly in the case of hypoallergenic (18.16 ± 7.89 µg l−1), lactose-free (11.37 ± 3.07 µg l−1), pre-term (11.48 ± 3.15 µg l−1) and soya (10.43 ± 4.05 µg l−1) formulae. The maximum theoretical estimated intake of infants fed on the studied formulae was lower than the upper limit safety for trivalent chromium of 1 mg kg−1 (14 µg kg−1 b.w. day−1) recommended by the experts of Council for Responsible Nutrition (Hathcock 2004; available at: http://crnusa.org/safety.html), amounting to about 10, 15–18 and 26% of the standard (adapted and follow-up) and toddler, soya, lactose-free and pre-term, and hypoallergenic formulae, respectively. Therefore, manufacturers are called upon to make continued efforts to routinely monitor chromium levels, particularly for specialised and pre-term formulae, and at the same time, might consider the inclusion of labelling the levels of chromium at least in these complex formulations.