Lactoferrin levels and unsaturated iron-binding capacity in colostrum of Brazilian women of two socioeconomic levels.

The objective of this study was to compare lactoferrin (LF) levels and unsaturated iron-binding capacity (UIBC) of colostrum from Brazilian women aged 20-38 years of low (N = 28) and high (N = 15) socioeconomic level. Both groups received a similar amount of supplemental iron (25-65 mg/day) during pregnancy. We also determined the relationship between LF levels and UIBC, and between these components and maternal iron status. Both groups (low and high socioeconomic level) showed adequate and similar mean hematocrit (35.0 +/- 1.3% and 35.9 +/- 1.3%, respectively) and serum ferritin (64 +/- 12 micrograms/l and 57 +/- 12 micrograms/l, respectively) levels. Furthermore, LF levels (5.7 +/- 0.9 mg/ml and 5.5 +/- 0.6 mg/ml) and UIBC (3.8 +/- 0.3 micrograms/ml and 3.1 +/- 0.3 micrograms/ml) were not significantly different in the two groups of women, nor were they related to maternal hematocrit or serum ferritin. UIBC was significantly (P = 0.009), although weakly positively correlated (r = 0.45) with LF levels, suggesting that other colostrum ligands may contribute substantially to the capacity of colostrum to bind exogenous iron.