Breast-milk fat concentrations of rural African women. 2. Long-term variations within a community

Abstract

1. Long-term variations in breast-milk fat concentration of mothers feeding on demand were studied in 120 rural West African women over a 12-month period. 2. The over-all mean 12 h breast-milk fat concentration was 39.3 g/l. 3. Mean breast-milk fat concentrations were affected by season in a manner which was correlated with seasonal changes in maternal subcutaneous fat stores (P less than 0.05) but which was unrelated to seasonal variations in maternal energy intake and breast-milk output. 4. Breast-milk fat concentrations were highest in early lactation, decreasing to a constant level during the first year. 5. There was significantly greater between-mother than within-mother variation in breast-milk fat concentrations measured in successive months, after correcting for season and stage of lactation (P less than 0.001). 6. Breast-milk fat concentrations were highest for primiparous mothers, decreasing to a constant level at parity 4 and higher. 7. A mother's relative breast-milk fat concentration was not correlated with her levels of dietary energy intake and breast-milk output but was positively correlated with her relative subcutaneous fat deposits (P less than 0.01).

PIP: The study was designed to determine whether long-term variations in breast-milk fat concentrations occur among underprivileged women feeding on demand and to examine to what extent these variations are related to breast milk volume. The influence of maternal energy intake and subcutaneous fat stores on breast-milk fat concentrations was also assessed. Study subjects were 120 rural Gambian women who were feeding their infants on demand. They were studied from 1 to 18 months post partum over a 12-month period from January to December 1979. The investigation formed part of a long-term study of nutrition and lactation in this community. There was a considerable variation in breast-milk fat concentrations between mothers and between measurements made in successive months on the same mother. It was possible to identify several factors which influenced the variations in breast-milk fat concentration. The overall mean 12 hour breast-milk fat concentration (g/l) was 39.3 g/l. Mean breast-milk fat concentrations were affected by season in a manner which was correlated with seasonal changes in maternal subcutaneous fat stores but which was unrelated to seasonal variations in maternal energy intake and breast-milk output. Breast-milk fat concentrations were highest for primiparous mothers. The concentrations decreased to a constant level at parity 4 and higher. A mother's relative breast-milk fat concentration was not correlated with her levels of dietary energy intake. Breast-milk output was significantly and positively correlated with her relative subcutaneous fat deposits.