Am J C/in Nuir l991;54:l093-1 100. Printed in USA. © 1991 American Society for Clinical Nutrition 1093 Urinary excretion of lignans and isoflavonoid phytoestrogens in Japanese men and women consuming a traditional Japanese diet14 Herman Adlercreutz, Hideo Honjo, Akane Higashi, Theodore Fotsis, Esa H#{228}m#{228}l#{228}inen, Takeshi Hasegawa, and Hiroji Okada ABSTRACT Epidemiologic studies revealed low mortality in hormone-dependent cancer in Japanese women and men consuming a traditional diet. We previously found that certain diphenolic food components, lignans and isoflavonoids, which arc converted to biologically active hormone-like substances by intestinal microflora, may be cancer-protective agents. Therefore, we studied urinary excretion of these compounds (enterolactone, enterodiol, daidzein, equol, and O-desmethylangolensin) in 10 women and 9 men in a rural village south of Kyoto, Japan. The subjects consumed a typical low-fat diet with much rice and soy products, fish, and vegetables. An isotope-dilution gas chro- matographic-mass spectrometric method was used for the assays. The urinary excretion oflignans was low but that of the isofla- vonoids was very high. The excretion ofisoflavonoids correlated with soybean-product intake. The low mortality in breast and prostate cancer ofJapancse women and men, respectively, may be due to the high intake of soybean products. Am J C/in Nutr 199l;54:1093-1 100. KEY WORDS Japanese, diet, urine, lignans, isoflavonoids, enterolactonc, enterodiol, daidzcin, equol, genistein, 0-des- methylangolensin, soybean, gas chromatography, mass spec- trometry, sex-hormone-binding globulin Introduction Mammalian lignans and isoflavonoid phytoestrogens, occur- ring in all studied animal and human biological fluids and in feces, are diphenolic compounds with molecular weights similar to those of steroid estrogens (1-3). Precursors in plants seem to occur as glycosides (4, 5), and the mammalian compounds arc produced from plant lignans and isoflavonoids by intestinal mi- croflora (6-8). Most ofthc original plant aglycones, such as for- mononetin, matairesinol, and secoisolariciresinol, occur only in very low concentrations in urine (9, 10). All compounds inves- tigated so far are weakly estrogenic but have shown many other biological activities, producing antiestrogenic (1-3); antiviral (11, 12); and antiproliferative, cytotoxic, and growth-inhibiting effects (3, 13-15). Studies indicate that they most likely stimulate the production ofsex-hormonc-binding globulin (SHBG) in the liver (2, 14-18) and may in this way significantly influence biological activity of the sex hormones. The higher SHBG values seen in vegetarians (2, 17-19) are probably due to the effect of these diphenolic compounds on liver synthesis of the protein (14). Studies in both young and old women with breast cancer and in various dietary groups indicate that urinary excretion of these compounds is highest in vegetarians and lower in omnivores and breast-cancer patients (2, 1 8, 20). It was shown that their urinary excretion correlates with the intake offiber-rich food (2, 17, 18). Japanese women and women of Japanese origin in Hawaii consuming a diet similar to the original traditional Japanese diet have low breast-cancer incidence and mortality (21-24). Simi- larly, Japanese men have low mortality with prostate cancer, although autopsy studies have found that the incidence of pros- tate cancer in Japanese and Western men arc similar (25-27). These cancers arc sex-hormone dependent and could potentially be influenced both by alterations of sex-hormone metabolism caused by lignans and isoflavonoids or by a direct effect of these compounds on their growth. Because ofthe associations between diet and these diseases, we decided to study the urinary excretion oflignans and isoflavonoid phytoestrogens in groups of Japanese men and women consuming a traditional diet. A preliminary report was published as an abstract (28). Subjects and methods Participants The subjects participating in this investigation were apparently healthy and were recruited in a small rural village south of Kyoto, I From the Department ofClinical Chemistry, University of Helsinki, Meilahti Hospital, Helsinki, Finland, and the Departments of Obstetrics and Gynecology and Preventive Medicine and the Laboratory of Gas Chromatography-Mass Spectrometry, Kyoto Prefectural University of Medicine, Kyoto, Japan. 2 Preliminary report published as an abstract. 3 Supported by Sigrid Jus#{233}lius and Finnish Cancer Foundations and the Medical Research Council of the Academy of Finland. 4 Address reprint requests to H Adlercreutz, Department of Clinical Chemistry, University of Helsinki, Meilahti Hospital, SF-00290 Helsinki, Finland. Received January 4, 1991. Accepted for publication April 17, 1991. by guest on July 6, 2015 ajcn.nutrition.org Downloaded from