A longitudinal study of manganese in human milk.

Flameless atomic absorption spectrophotometry has been applied to the analysis of manganese in human milk samples. Twenty-seven breast-feeding mothers donated 229 individual milk samples between the 2nd week and the 9th month of lactation. The milk samples were representative of every feed in a period of 24 hours, foremilk and hind-milk in equal proportions. The median concentration of manganese declined from the initial value of 5.9 microgram/l to about 4 microgram/l before the 2nd month of lactation, remained at this level up to the 5th--6th month of lactation and showed a tendency to rise thereafter. The values presented here are noticeably lower than most of those reported earlier. It remains an open question whether the manganese concentration is exceptionally low in Finnish human milk or whether the great difference from most earlier studies may reflect problems of contamination or technical difficulties when less sensitive analytical methods have been used.