Maskarinec G, Singh S, Meng L, Franke A A
Cancer Research Center of Hawaii, Honolulu 96813, USA.
Cancer Epidemiol Biomarkers Prev. 1998 Jul;7(7):613-9.
Isoflavones are present in soybeans and its products in concentrations up to 300 mg/100 g, have estrogenic and antiestrogenic properties, and may be protective against hormone-related cancers. The purpose of this cross-sectional study was to investigate the association between urinary isoflavone excretion and self-reported soy intake. A total of 102 women of Caucasian, Native Hawaiian, Chinese, Japanese, and Filipino ancestry completed a dietary questionnaire for soy products consumed during the last year and during the 24-h period before urine collection. Overnight urine samples were analyzed for coumestrol and the soy isoflavones genistein, daidzein, and glycitein and their main human metabolites by reverse-phase high-pressure liquid chromatography. Soy protein and isoflavone intake (predominantly from tofu) were estimated using published nutritional databases. Wilcoxon's rank-sum test scores and Spearman rank correlation coefficients were computed. Japanese women excreted more daidzein, genistein, and glycitein than did Caucasian women, whereas Caucasian women excreted slightly more coumestrol. Soy intake differed significantly among ethnic groups. Dietary soy protein and isoflavone intakes during the previous 24 h were positively related to urinary isoflavone excretion [rs = 0.61 (P < 0.0001) and 0.62 (P < 0.0001), respectively]. Urinary excretion of isoflavones was also related to annual dietary soy protein and isoflavone intake [rs = 0.32 (P < 0.0012) and 0.31 (P < 0.0016), respectively]. The strong correlation between urinary isoflavone excretion and self-reported soy intake validates the dietary history questionnaire that is now used in a study exploring dietary risk factors for breast cancer.
异黄酮存在于大豆及其制品中，浓度高达300毫克/100克，具有雌激素和抗雌激素特性，可能对激素相关癌症有保护作用。这项横断面研究的目的是调查尿异黄酮排泄量与自我报告的大豆摄入量之间的关联。共有102名具有白种人、夏威夷原住民、华裔、日裔和菲律宾裔血统的女性完成了一份关于过去一年以及尿液收集前24小时内所食用豆制品的饮食问卷。通过反相高压液相色谱法分析过夜尿液样本中的香豆雌酚、大豆异黄酮染料木黄酮、大豆苷元和黄豆黄素及其主要人体代谢物。使用已发表的营养数据库估算大豆蛋白和异黄酮摄入量（主要来自豆腐）。计算了威尔科克森秩和检验分数和斯皮尔曼等级相关系数。日本女性排泄的大豆苷元、染料木黄酮和黄豆黄素比白种女性多，而白种女性排泄的香豆雌酚略多。不同种族之间的大豆摄入量差异显著。前24小时的膳食大豆蛋白和异黄酮摄入量与尿异黄酮排泄呈正相关[分别为rs = 0.61（P < 0.0001）和0.62（P < 0.0001）]。异黄酮的尿排泄量也与年度膳食大豆蛋白和异黄酮摄入量相关[分别为rs = 0.32（P < 0.0012）和0.31（P < 0.0016）]。尿异黄酮排泄量与自我报告的大豆摄入量之间的强相关性验证了目前在一项探索乳腺癌饮食风险因素的研究中使用的饮食史问卷。
