BREAST-MILK CALCIUM CONCENTRATIONS DURING PROLONGED LACTATION IN BRITISH AND RURAL GAMBIAN MOTHERS

Detailed investigations of breast-milk calcium concentrations during 2 years of lactation have been conducted in Cambridge, UK, and rural Gambia. Mature milk concentrations remained steady for 3 months but declined during months 4-12 by over 25% (p<0.001). The pattern was identical in both communities despite differences in breast-feeding practices. Calcium concentrations were not related to feed frequency or breast-milk sodium concentrations, suggesting that breast involution is not responsible for the decrease after 3 months. Breast-milk calcium concentrations were characteristic of the individual, varied twofold between mothers and were independent of maternal age, parity and milk output. Gambian breast-milk contained 19% less calcium than Cambridge milk, throughout lactation (p<0.001). The extent to which this reflected the lower calcium intakes of Gambian mothers is unknown. Further studies are required to determine factors regulating breast-milk calcium secretion.