Lactoferrin content

Lactoferrin s role in iron absorption was demonstrated by the addition of lactoferrin, presumably iron-saturated, to a lactoferrin free simulated human milk. Administered to adults it did not increase iron absorption (13). The addition of apolactoferrin was shown to actually inhibit iron uptake by rat and guinea-pig in everted duodenal sacs, while the addition of Fe 2- lactoferrin had no effect on uptake of iron (14). An additional study demonstrated a negative relationship between duodenal lactoferrin concentration and iron absorption in adults (15). These results would suggest that lactoferrin has no role or even a negative role in iron absorption. Further, additional studies brings into question the role, if any at all, that lactoferrin has in iron absorption. McMillan et al. (13) have shown that the iron in human milk, despite the high lactoferrin content, is more readily absorbed than iron from a simulated human milk of comparable iron content. The... 

Lactoferrin is a major component of human but not bovine milk (Bezkorovainy, 1977). Its main function in human milk appears to be as a bacterial growth inhibitor, since its iron saturation level is only 9-10%, and human milk therefore possesses a high UIBC status. In addition, lactoferrin may act as a vehicle for the absorption of iron by the human neonate (Cox et al., 1979). Human milk, because of its high lactoferrin content, exerts a much greater bacteriostatic effect than does bovine milk (Kochan et al., 1977). For this and other reasons, breast-fed human infants have a much lower incidence of gastrointestinal disorders than do bottle-fed infants (Goldman, 1973). 

Lactoferrin contents rise dramatically in the milks of mastitic cattle. This apparently represents a normal physiological defense mechanism similar to the nutritional immunity discussed in a previous section, except that here not only the UIBC but also TIBC-values of the milks increase drastically. In such milks, lactoferrin values may be as high as 6 mg/ml, lactoferrin thus becoming a major milk protein component. It is apparently synthesized by the epithelial cells rather than being released by the neutrophils that are also present in such milks (Harmon et al., 1976), The function of the transferrins in other types of infections in cattle have not yet received much attention, and should represent a fertile area for future research activity. 

Mother s milk is an often coined term for products that mimic the natural mother s milk contents. Actual human mother s milk contains about 40-50% casein and 50-60% whey, and about 17% lactoferrin with no beta-lactoglobulin. As I said earlier, mother s milk contains alfa lactoglobulin. This is very different from cow s milk which contains about 80% casein and 20% whey with 1% lactoferrin being average. Lactoferrin has anti-viral activity, and is a potent immune system booster. Obviously this is an advantage for new born human (rug rats) since they lack complete immune system functions. Remember the fact that human mother s milk dominant protein fraction is alfa-lactalbumin Well, there is a research project on going which claims acid folded alfa-... 

It is interesting to note that /3-lactoglobulin is the major protein in cow s milk whey, but it is absent from human milk whey. However, the content of a-lactoalbumin and immunoglobulins (Ig) is higher in human than in cow s milk whey. Serum albumin and lactoferrins are found in similar concentrations in human and cow s milk whey, and the amount of lactoferrin is higher in colostrum than in mature milk. In any case, lactoferrin is present in milk throughout the lactation period. 

The predominating form of iron in animal tissues is haem (particularly myoglobin and haemoglobin). In egg white, iron is bound in conalbumin, and in the yolk to phosphoprotein phosvitin. Milk contains the iron metaUoprotein lactoferrin and part of the iron is bound to casein. Conalbumin and lactoferrin are structurally similar to serum transferrin. In plants, iron is bound in various complexes, especially with phytic acid, aUphatic hydroxycarboxyhc acids, aminocarboxyhc acids, thiols, phenolic substances, nucleotides, peptides and proteins. The iron content in selected foods is shown in Table 6.8. Foods rich in iron are offal dishes, meat, eggs, pulses, tea and cocoa. Moderate amounts of iron are found in fish, poultry, cereals, spinach, parsley and nuts. Low levels of iron are present in milk, dairy products, fats and oils, potatoes and most fruit. 

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