TY - JOUR
T1 - Bioavailability of isoflavone phytoestrogens in postmenopausal women consuming soya milk fermented with probiotic bifidobacteria
AU - Tsangalis, Dimitri
AU - Wilcox, Gisela
AU - Shah, Nagendra P.
AU - Stojanovska, Lily
N1 - Funding Information:
The Australian Research Council’s Strategic Partnership with Industry (Sanitarium Health Food Company) for Research and Training scheme funded this research. We gratefully acknowledge the assistance given by Professor Paul Komesaroff (Alfred Hospital, Melbourne, Victoria, Australia) when preparing the ethics application and documentation for subjects. We also would like to thank Dr John Ashton of Sanitarium Health Food Company for his support and for providing the soya germ powder required for soya milk manufacture.
PY - 2005
Y1 - 2005
N2 - We investigated the effects of consuming an isoflavone aglycone-enriched soya milk containing viable bifidobacteria on urinary isoflavone excretion and percentage recovery. Sixteen postmenopausal women were randomly divided into two groups to consume either fermented or non-fermented soya milk. Each group participated in a double-blind, crossover study with three 14d supplementation periods, separated by a 14 d washout. Subjects ingested three daily dosages of isoflavone via the soya milk and collected four 24 h pooled urine specimens per supplementation period. Soya milks were prepared with soya protein isolate and soya germ, followed by fermentation with bifidobacteria. Isoflavone levels were quantified using HPLC. Non-fermented soya milks at 20, 40 and 80 mg isoflavone/200ml contained 10%, 9% and 7% aglycone, respectively, with their fermented counterparts containing 69%, 57% and 36 % aglycone (P<0.001). A trend to a greater percentage urinary recovery of daidzein and glycitein was observed among women consuming fermented soya milk at a dosage of 40 mg isoflavone (P=0.13). A distinct linear dose response for the fermented soya milk group (R2=0.9993) compared with the non-fermented group (R 2 = 0.8865) suggested less interindividual variation in isoflavone absorption. However, total urinary isoflavone excretion was similar for both groups (P>0.05), with urinary isoflavone recovery at approximately 31%. Increasing the isoflavone dosage correlated positively with its urinary excretion, but urinary percentage recovery of isoflavone was inversely related to dosage level. Hence, a modest dosage ranging from 20 to 30 mg/d may provide the most bioavailable source of isoflavone, regardless of whether it is via an aglycone-rich fermented soya milk or a glucoside-rich soya milk.
AB - We investigated the effects of consuming an isoflavone aglycone-enriched soya milk containing viable bifidobacteria on urinary isoflavone excretion and percentage recovery. Sixteen postmenopausal women were randomly divided into two groups to consume either fermented or non-fermented soya milk. Each group participated in a double-blind, crossover study with three 14d supplementation periods, separated by a 14 d washout. Subjects ingested three daily dosages of isoflavone via the soya milk and collected four 24 h pooled urine specimens per supplementation period. Soya milks were prepared with soya protein isolate and soya germ, followed by fermentation with bifidobacteria. Isoflavone levels were quantified using HPLC. Non-fermented soya milks at 20, 40 and 80 mg isoflavone/200ml contained 10%, 9% and 7% aglycone, respectively, with their fermented counterparts containing 69%, 57% and 36 % aglycone (P<0.001). A trend to a greater percentage urinary recovery of daidzein and glycitein was observed among women consuming fermented soya milk at a dosage of 40 mg isoflavone (P=0.13). A distinct linear dose response for the fermented soya milk group (R2=0.9993) compared with the non-fermented group (R 2 = 0.8865) suggested less interindividual variation in isoflavone absorption. However, total urinary isoflavone excretion was similar for both groups (P>0.05), with urinary isoflavone recovery at approximately 31%. Increasing the isoflavone dosage correlated positively with its urinary excretion, but urinary percentage recovery of isoflavone was inversely related to dosage level. Hence, a modest dosage ranging from 20 to 30 mg/d may provide the most bioavailable source of isoflavone, regardless of whether it is via an aglycone-rich fermented soya milk or a glucoside-rich soya milk.
KW - Bifidobacteria
KW - Bioavailability
KW - Isoflavone
KW - Postmenopausal women
KW - Soya milk
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U2 - 10.1079/BJN20041299
DO - 10.1079/BJN20041299
M3 - Article
C2 - 16022756
AN - SCOPUS:24044475615
SN - 0007-1145
VL - 93
SP - 867
EP - 877
JO - British Journal of Nutrition
JF - British Journal of Nutrition
IS - 6
ER -