Breast milk composition: fat content and fatty acid composition in vegetarians and non-vegetarians.

Milk from vegetarians contained a lower proportion of fatty acids derived from animal fat and a higher proportion of polyunsaturated fatty acids derived from dietary vegetable fat. No significant differences were observed between dietary groups in percent fat in the milk or in proportions of fatty acids synthesized de novo in the mammary gland. Among women consuming less than 35 g animal fat per day, percent milk fat was significantly correlated with animal fat intake. Among women consuming greater than 35 g animal fat, percent fat in milk was positively correlated with percent of C10:0, C12:0, and C18:3 and negatively correlated with percent of C16:0 and C18:0 in the milk fat. These findings suggest that there is a maximum amount of C16:0 and C18:0 that can be taken up from the blood and subsequently secreted into the milk.