Abstract Number: ?? Gut flora influence on isoflavone bioavailability Adrian A Franke, Cancer Research Center of Hawaii, Honolulu, HI; Scott A Hundahl, Queen's Cancer Institute, Honolulu, HI; Laurie J Custer, Cancer Research Center of Hawaii, Honolulu, HI Dietary isoflavones derive particularly from soy foods and are implicated in the prevention of breast, prostate, lung, bladder, and endometrial cancer. In order to research the unclear influence of the human gut flora in conversion and absorption of isoflavonoids plasma levels and urinary excretion rates of isoflavonoids were measured in subjects with a reduced gut flora as a result of mechanical bowel preparation followed by oral antibiotic treatment. After intake of a soy drink containing 99 micromoles of isoflavone glycosides and 8 micromoles of isoflavone aglycones [Proc. Soc. Exp. Biol. Med. 217, 263 (1998)] we found a profound difference in patterns of plasma levels and urinary excretion rates of isoflavonoids after antibiotic treatment vs. control: urinary isoflavone recovery was lower by over 50% in the first 24-hours, but higher by 38% in the second 24-hours. Urinary excretion rates were significantly correlated with plasma levels confirming our previous findings [Biochem. Soc. Trans. 27, 308-318 (1999)]. This gives evidence that the gut flora in humans cleaves isoflavone glycosides more efficiently than mucosa glucosidases but also degrades isoflavones in agreement with in-vitro results [J. Nutr. 125, 2307-2315 (1995)]. It also shows convincingly that isoflavones are taken up in the large intestine. The gut flora may determine the bioavailability of valuable dietary cancer preventive agents. Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.