Osmolalities of bottle- and breast-milk fed to poor urban Brazilian infants.

Feeding practices related to osmotic strength of bottle-milk and breast-milk were studied in 133 families with infants less than 1 year of age in a poor urban settlement in Brasilia, Brazil. Osmolality [mean (SEM)] of breast-milk [318.8 (4.46) mOsm/kg water] was significantly less than that of bottle-milk [568.7 (29.9) mOsm/kg water]. The wide range of osmotic strength (253.7-1,380.0 mOsm/kg water) found in bottle-milk was partly due to the predominant use (82%) of powdered cow's milk among non-breastfeeders and its improper reconstitution. Diarrhoea and feeding management are also discussed.