ELECTROLYTE-COMPOSITION OF HUMAN BREAST-MILK BEYOND THE EARLY POSTPARTUM PERIOD

The electrolyte composition of breast milk beyond 6 months postpartum has not been extensively examined, particularly chloride concentration s. A total of 140 samples of breast milk from 30 breast-feeding mother s were collected and analyzed. Mean mother's values +/- standard error of sodium (141 +/- 17 mg/L), potassium (480 +/- 11 mg/L), and chlorid e (452 +/- 32 mg/L) were found to be stable after 4 months postpartum until weaning commenced. Considerable variability was found for each c onstituent, equally divided between intra-individual and inter-individ ual for chloride and potassium, and predominantly intra-individual for sodium and lactose. In light of reported nutritional deficiency state s involving electrolytes in exclusively breast-fed infants, it is poss ible that the variability of breast milk electrolyte concentrations ma y adversely affect infant nutrition in selected cases of older exclusi vely breast-fed infants. (C) Elsevier Science Inc, 1997.