URINARY ISOFLAVONOID PHYTOESTROGEN AND LIGNAN EXCRETION AFTER CONSUMPTION OF FERMENTED AND UNFERMENTED SOY PRODUCTS

Objective To compare the effects of consumption of fermented and unfer mented soy products on excretion of urinary isoflavonoid phytoestrogen s and Lignans in healthy men. Design A randomized, crossover trial con sisting of two B-day feeding periods following 5 days of baseline data collection. Subjects Healthy men, aged 20 to 40 years, were recruited from the University of Minnesota Twin Cities community. Of the 22 sub jects who began the study, 17 completed all feeding periods. Intervent ions Fermented soy product (112 g tempeh) or unfermented soy (125 g so ybean pieces) was consumed during each controlled feeding period. Main outcome measure Urine samples collected while subjects consumed their habitual diets and on the last 3 days of each feeding period were ana lyzed for isoflavonoid and lignan content by isotope dilution gas chro matography-mass spectrometry. Statistical analysis performed Compariso ns of isoflavonoid and Lignan excretion were analyzed using the genera l Linear model procedure. Orthogonal contrasts were used to determine treatment differences of interest. Results Urinary excretion of isofla vonoids (equol, O-desmethylangolensin [O-DMA], daidzein, genistein) wa s higher and excretion of lignans (enterodiol, enterolactone) was lowe r when subjects consumed soy-supplemented diets than when they consume d their habitual diets (P<.05). Urinary isoflavonoid excretion and Lig nan excretion were similar when subjects consumed tempeh and soybean p ieces diets; however, recovery of daidzein and genistein was significa ntly higher when subjects consumed the tempeh diet than when they cons umed the soybean pieces diet (P<.002). When fed soy, 5 of 17 subjects excreted high amounts of equol. These five subjects tended to excrete less O-DMA and daidzein than the 12 subjects mho excreted low amounts of equol (P<.06). Conclusions Fermentation of soy decreased the isofla vone content of the product fed but increased the urinary isoflavonoid recovery. This finding suggests that fermentation increases availabil ity of isoflavones in soy.