Breast-Milk Calcium Concentrations During Prolonged Lactation in British and Rural Gambian Mothers

Detailed investigations of breastmilk calcium concentrations during 2 years of lactation have been conducted in Cambridge United Kingdom and rural Gambia. Mature milk concentrations remained steady for 3 months but declined during months 4-12 over 25% (p<0.001). The pattern was identical in both communities despite differences in breastfeeding practices. Calcium concentrations were not related to feed frequency or breastmilk sodium concentrations suggesting that breast involution is not responsible for the decrease after 3 months. Breastmilk calcium concentrations were characteristic of the individual varied 2-fold between mothers and were independent of maternal age parity and milk output. Gambian breastmilk 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 breastmilk calcium secretion. (authors)