Trace elements human milk

In addition to the major salt constituents discussed up to this point, the elements listed in Table 1.3 have been detected in normal bovine milk by spectroscopic and chemical analyses. They include a large number of metals, the metalloids As, B, and Si, and the halogens F, Br, and I. The subject of trace elements in milk has been reviewed comprehensively (Archibald 1958 Murthy 1974 Underwood 1977). Their significance for human nutrition is discussed in Chapter 7. 

The multielement capabilities of ICP-MS have also been extensively employed for the characterization of human milk in studies aiming at verifying the reference ranges (RRs) proposed for both essential and harmful elements, and contribute to the establishment of RRs for new (ultratrace) elements [63-65]. Transfer of selected elements from food into human milk [66], changes in milk composition during lactation [67], and adequacy of the intakes of essential trace elements in breast-fed infants [63, 68] are some of the other topics investigated in related studies. For those infants who are not breast-fed, the nutritional... 

E. Rossipal, M. Krachler, Pattern of trace elements in human milk during the course of lactation, Nutr. Res., 18 (1998), 11-24. 

M. Krachler, T. Prohaska, G. Koellensperger, E. Rossipal, G. Stingeder, Concentrations of selected trace elements in human milk and in infant formulas determined by magnetic sector held inductively coupled plasmaDmass spectrometry, Biol. Trace Elem. Res., 76(2) (2000), 97D112. 

TOTAL ANALYSIS AND DISTRIBUTION OF TRACE ELEMENTS IN HUMAN, COW, AND FORMULA MILK... 

Minerals The main mineral constituents in milk are calcium and chlorine, magnesium chloride, phosphate, and citrate. Minerals in milk are mainly present as soluble salts or in colloidal form associated with caseins. Their concentrations may vary enormously. Thus, the minerals present in milk can be classified according to their concentration level as major and minor elements, with small quantitative contributions from trace and ultratrace elements. The total content of minerals in mammalian milks should correspond to the growth requirements of each biological species. Accordingly, the mineral total content in cow milk is four times higher than in human milk. 

The most significant differences are found for all major elements (e.g., Ca, K, Mg, Na, and P). However, the ratio Ca P, which is related to structural functions extremely important for the correct development of the newborn, is higher in human milk. Despite their low levels in milk, minor and trace elements play a central role in the organism, since their deficiency or excess may generate undesirable effects in the newborn. This fact and the centrality of milk in the human diet explain the growing interest in the determination of trace elements in milk [6-8], Table 13.6 summarizes the concentration levels for major, trace and ultratrace elements in human and cow milk. 

Inductively Coupled Plasma Atomic Emission Spectrometry ICP-AES is a technique half-way between FAAS and ET-AAS in terms of detection power. Among all ICP-AES features its robustness against matrix effects and its ability to carry out multielemental analysis predominate as the most advantageous [76-80], Multielemental analysis has also been successfully used to establish reference values [6, 76, 81-84] for many major and trace essential elements in different matrices of biological and nutritional interest, particularly in milk samples [81-83], Reference values for minor and trace element in human milk are collected in Table 13.8. 

TABLE 13.8. Overall Reference Concentration Ranges for Major and Trace Elements in Human Milk... 

Several publications have addressed multielemental analysis in milk whey, cow s milk, human milk and infant formulas using SF-ICP-MS (see Table 13.9). Rivero Martino et al. [96] reported the multielemental analysis of a wide range of elements in human, cow s, and formula milk whey samples. Milk whey was obtained by centrifugation and then diluted 1 4 (v/v) with milliQ water for minor and trace elemental analysis (Al, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sr, and Zn) and 1 1999 (v/v) for major elements (Ca, Mg, and Na). Gallium, Rh,... 

T. Prohaska, G. Kollespenger, M. Krachler, K. De Winne, G. Stingeder, L. Moens, Determination of trace elements in human milk by inductively coupled plasma sector field mass spectrometry (ICP-SFMS), J. Anal. Atom. Spectrom., 15 (2000), 335-340. 

E. Coni, A. Stacchini, S. Caroli, P. Falconieri, Analytical approach to obtaining reference values for minor and trace elements in human milk, J. Anal. Atom. Spectrom., 5 (1990), 581-586. 

J. K. Friel, W. L. Andrews, S. E. Jackson, H. P. Longerich, C. Mercer, A. McDonald, B. Dawson, B. Sutradhar, Elemental composition of human milk from mothers of premature and full-term infants during the first three months of lactation, Biol. Trace Elem. Res., 67 (1999), 225-247. 

As detailed in the earlier chapter on milk, from an analytical viewpoint the total determination of trace elements in human milk samples as such is still an open issue because decomposition, preconcentration, and storage of trace analytes in solutions are often a source of concern. The accuracy of the analytical results can, in fact, be endangered by these pretreatments. There are relatively few methods for such total direct analytical determinations, and in many cases they are still inadequate to meet the needs of the analyst. 

Human milk can be considered the optimal food for infants. It contains all the macronutrients and micronutrients necessary for the correct development of the newborn and at the adequate levels. When infants are not breast-fed, or breastfeeding is discontinued very early, formula milks are used instead. Therefore, it is important to evaluate the capacity of formulas to deliver satisfactory quantities of minerals and trace elements that can be bioavailable to the children in order to cover their biological needs. This fact explains the need to perform trace elements speciation analysis in formula milk. Thus, the speciation results obtained in formulas and published so far are critically evaluated here and compared with those obtained in human milk. 

Human milk (or the substitute food, formula milk) is the only source of essential trace elements for newborns. To ensure the optimum development of the baby, mother s milk contains essential elements at the adequate levels. However, today it is well known that bioavailability, biological activity, nutritional value, as well as toxicity and metabolism of trace metals and metalloids strongly depend of their... 

P. Bratter, B. Gercken, U. Rosick, A. Tomiak, Speciation of trace elements in human milk and milk formulas, in P. Bratter, P. Schramel (eds), Trace Element Analytical Chemistry in Biology and Medicine, Vol. 5, Walter de Gruyter, Berlin, 1988, pp. 145-156. 

B. Michalke, P. Schramel, Selenium speciation in human milk with special respect to quality control. Biol. Trace Element Res., 59 (1997), 45-56. 

B. Lonnerdal, Regulation of mineral and trace elements in human milk exogenous and endogenous factors, Nutr. Rev., 58(8) (2000), 223-229. 

R. M. Parr, E. M. DeMaeyer, V. G. Iyengar, A. Byrne, G. F. Kirkbright, G. Schoch, L. Niinisto, O. Pineda, H. L. Vis, Y. Hofvander, A. Omoloulu, Minor and trace elements in human milk from Guatemala, Hungary, Nigeria, Philippines, Sweden, and Zaire, Biol. Trace Elem. Res., 29 (1991), 51-75. 

P. Schramel, G. Lill, S. Hasse, B. J. Klose, Mineral- and trace element concentrations in human breast milk, placenta, maternal blood, and the blood of the newborn, Biol. Trace Elem. Res., 16 (1988), 67-75. 

C. Ekmekcioglu, Intestinal bioavailability of minerals and trace elements from milk and beverages in humans, Nahrung, 44 (2000), 390-397. 

Infant formulas are supplemented with Mn and other trace elements in the form of inorganic salts. Whether these supplemented minerals have different bioavailabilities from their counterparts found naturally in human milk or bovine milk has not been extensively investigated. Chan and associates previously reported that Mn was bound to different molecules in human milk, bovine milk and infant formula (12). Inadequate or excessive intake of Mn has severe effects especially during infancy (1,13). It is therefore important to evaluate the bioavailability of Mn in different milk diets. To achieve this aim, suckling rats and everted intestinal sacs derived from these animals were used as systems to study the absorption of Mn from rat milk, human milk, bovine milk and infant formula. Effect of age on Mn absorption in suckling rat pups from various milk diets was also investigated. Some of the data presented in this article have been reported previously (14-17). 

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