The effect of hydrogenated fat in the diet of nursing mothers on lipid composition and prostaglandin content of human milk.

To study the effects of hydrogenated fat in the maternal diet on lipid composition and prostaglandin content of human milk, eight nursing mothers, 2 months postpartum, were provided with two 5-day diets in a cross-over design with an intervening 2-day period. Diets for the two periods were identical except that sources of hydrogenated fat were used in the meals for one period and nonhydrogenated fat in the other. Trans-isomers of octadecenoic acid (18:lt) comprised 11.8% of the total fatty acids in the hydrogenated fat diet compared with 1.0% in the nonhydrogenated fat diet. The 18:lt content of milk collected daily during hydrogenated fat consumption was 6.5% of the total fatty acids and was significantly higher (p less than 0.01) than the 18:lt content (1.8% of the total fatty acids) of milk collected during nonhydrogenated fat consumption. The amount of 18:lt in the milk was positively correlated (r = 0.909) with the 18:lt content in the previous day's diet. Although detectable concentrations of prostaglandins PGF2 alpha and PGE were found in human milk, their concentrations were not affected by hydrogenated fat in the maternal diet.