Am. Hutchins et al., URINARY ISOFLAVONOID PHYTOESTROGEN AND LIGNAN EXCRETION AFTER CONSUMPTION OF FERMENTED AND UNFERMENTED SOY PRODUCTS, Journal of the American Dietetic Association, 95(5), 1995, pp. 545-551
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.