Lm. Kirkman et al., URINARY LIGNAN AND ISOFLAVONOID EXCRETION IN MEN AND WOMEN CONSUMING VEGETABLE AND SOY DIETS, Nutrition and cancer, 24(1), 1995, pp. 1-12
Urinary lignan and isoflavonoid excretion were examined in 11 men and
9 women consuming four nine-day controlled experimental diets: basal (
vegetable free), carotenoid vegetable (carrot and spinach), cruciferou
s vegetable (broccoli and cauliflower), and soy (tofu and textured veg
etable protein product). Three-day urine collections (Days 7-9) were a
nalyzed for lignans and isoflavonoids with use of isotope-dilution gas
chromatography-mass spectrometry. Urinary excretion of the lignans en
terodiol and enterolactone was higher during the carotenoid and crucif
erous vegetable diets than during the basal diet (p = 0.0001), suggest
ing that these vegetables may provide a source of mammalian lignan pre
cursors. Urinary excretion of the isoflavonoids equol, O-desmethylango
lensin, daidzein, and genistein was higher when subjects consumed soy
diets than when they consumed the other test diets (p < 0.02). Gender
differences in lignan excretion were observed. Men excreted more enter
olactone (p = 0.006) and less enterodiol (p = 0.013) than women, imply
ing a gender difference in colonic bacterial metabolism of lignans. Th
ere was no effect of gender on isoflavonoid excretion.