Zinc status of lactating Egyptian mothers and their infants: effect of maternal zinc supplementation

In this study, assessment of serum, breast milk, and hair and nail zinc (Zn) was done in 60 primiparous women and their neonates to evaluate the effect of maternal Zn supplementation on maternal and infant Zn stores and on the infants' physical growth. Thirty mothers were given a multivitamin preparation (lacking Zn) and the other 30 were additionally supplied with Zn for 2 months, then reassessment of Zn levels was done. The results revealed diurnal variation in colostral Zn concentrations. Lactation depleted the maternal Zn stores whereas infant stores were replenished regardless of maternal supplementation. Zn supplementation caused significantly higher maternal hair, nail, and breast milk Zn levels but did not affect the infants' levels or their growth. In conclusion, Zn supplementation for lactating women positively influenced breast milk Zn concentrations and maternal body stores although it had no significant influence on the infants' physical growth. Women who plan to nourish their infants by breast milk alone should ask for dietary consultation to obtain this nutrient from a varied balanced diet rather than from supplementation. In addition, the evident diurnal variation in breast milk Zn emphasizes that working mothers should be advised to express their morning milk, which is richer in Zn, for the maximum benefit of their infants. (C) 2005 Elsevier Inc. All rights reserved.