Interrelation among dietary energy and fat intakes, maternal body fatness, and milk total lipid in humans.

The relationship between maternal dietary intakes of energy or fat maternal body composition and the milk fat concentration is an important element in understanding the role of breast-milk in infant nutrition. In most studies in both developing and developed countries, no relation between maternal energy intake and milk fat content was observed. In only one published study, in which maternal fat intake comprised a very low 5% of calories, was a short term reduction in milk lipid observed in some subjects. On the other hand, a positive relation between maternal fatness and milk fat is evident in both well-nourished and under-nourished women when appropriate methodologies have been used. Low milk fat concentrations are associated with higher milk volumes probably because infant demand determines milk intake, compensating, at least partially, for low milk fat. No impairment of infant growth was associated with low milk fat, in studies where it has been measured. The mechanism for the relationship between body fat and milk fat is a fertile field for additional investigation.