Maternal diet and fatty acid pattern of breast milk.

The effect of habitual maternal diet on the fatty acid composition of breast milk was evaluated by conducting a dietary survey of lactating mothers and by analyzing their breast milk samples. The mean energy intake of the mothers was 9.8 MJ during the first survey week (20 mothers, 6-8 weeks post partum) and 8.6 MJ during the second survey week (13 mothers, 17-22 weeks post partum). Protein, fat and carbohydrate intake comprised 16%, 39% and 45% of the total energy intake, respectively. The breast milk samples contained 3.8% fat. Half of the fatty acids of the diets and breast milk were saturated (S), and one third were monoenoic. Polyunsaturated (P) fatty acids comprised 15% in the diets and 13% in the breast milk. The average P/S ratio was 0.3 both in the diets and breast milk samples. Carbohydrate intake correlated negatively (p less than 0.05) with arachidic acid of breast milk, and both protein and fat intakes correlated positively (p less than 0.05) with palmitic acid of breast milk. The maternal diet had no effect on the total fat content of breast milk. A positive correlation was found between the saturated (p less than 0.05) and polyunsaturated (p less than 0.01) fatty acids of maternal diet and breast milk. As to the single fatty acids, the only significant correlation was found with linoleic acid (p less than 0.01). However, the variation of linoleic acid intake explained only about 27% of the variation occurring in the breast milk.

The effects of the dietary intakes of copper, iron, manganese, and zinc on the trace element content of human milk.

Fifteeen breast-feeding mothers who volunteered for a study of trace elements in human milk, kept two 7-day food records during the course of lactation. The 1st survey week ranged from 6 to 8 weeks and the 2nd survey week from 17 to 22 weeks postpartum. The milk samples submitted for analysis represented a sample of every feed during a period of 24 hr and contained foremilk and hindmilk in equal proportions. The 7-day food records were handled by a computing system to give an average daily food consumption and nutrient intake, but iron was the only trace element given by the system. In order to estimate the trace element intakes of the mothers, mixtures were prepared to represent the average daily food consumption. The trace element concentrations of the mixtures and milk samples were analyzed using the atomic absorption spectrophotometric method. The estimated average daily copper intake was 1.8 mg, the iron intake 16 mg, the manganese intake 5 mg, and the zinc intake 13 mg. The mean copper, iron, manganese, and zinc concentrations of the milk samples were 0.36 +/- 0.07 mg/liter, 0.40 +/- 0.10 mg/liter, 4.5 +/- 1.8 microgram/liter, and 1.89 +/- 0.74 mg/liter for the 1st survey week and 0.21 +/- 0.07 mg/liter, 0.29 +/- 0.09 mg/liter, 4.0 +/- 1.5 microgram/liter, and 0.72 +/- 0.44 mg/liter for the 2nd survey week. A significant positive correlation (P less than 0.01) was observed in the 2nd survey week between maternal manganese intake and the manganese content of human milk. The intake of copper, iron, and zinc, at the present level of intake, did not seem to affect the corresponding trace element levels in human milk.