RESUMO
Dietary fatty acid composition is known to affect various aspects of eicosanoid metabolism. This research was conducted to evaluate effects of a diet similar to the US average consumption in 1974 (40 en% fat, polyunsaturated to saturated fatty acid ratio, P/S = 0.3) or a diet modified to contain 30 en% fat, P/S = 1.0, on eicosanoid metabolism in young women. Following a period on self-selected diets, women in Nebraska and Iowa were fed the diets for 28-day periods in a crossover design. Urinary eicosanoids, sodium (Na) excretion, and blood pressure were determined. Diet effects were confounded by carryover effects. For urinary eicosanoids the sequence of higher saturated fat (SFA) followed by lower SFA resulted in significantly greater excretion, whereas the reverse order of diets did not cause significant changes. Diastolic blood pressure was not affected by diet, but systolic pressure was lower with the modified diet in the lower to higher-SFA sequence. The change from self-selected to experimental diets does not seem to account for the carryover effects. The interpretation is that linoleate is depleted from tissues more slowly than it is repleted. Effects upon Na excretion were related to SFA more than to linoleate in the diet.