大豆以及其他豆类中植物来源的化学物质具有广泛营养学价值，如大豆异黄酮是具有健康保护和治疗学意义的非固醇类物质。由于它能与雌激素受体结合，具有雌激素样作用，故称之为植物雌激素。
随着近年研究的深入，人们发现大豆以及大豆中某些化学物质对多种疾病包括肿瘤、心血管疾病、骨质疏松症和神经退行性疾病等有预防和治疗作用，相关研究的兴趣也日渐增加。
其中，被广泛认可的是大豆等豆类植物中的化学物质可以减少罹患子宫内膜癌的风险，但迄今为止，现有的流行病学研究报告结果并不能支持这一观点。
美国夏威夷癌症研究中心和洛杉矶南加州大学的研究人员为了解决这一问题，在一项最新研究中分析了豆科植物、大豆、豆腐以及大豆异黄酮的摄入量与绝经妇女罹患子宫内膜癌风险的关系性，研究结果发表在JNCI杂志上。
为了分析饮食情况与子宫内膜癌风险之间的关系，研究人员收集了在1993年8月至1996年8月之间，未进行子宫切除术的46,027例绝经女性的相关资料。科研人员对这些女性平均随访13.6年，其中有489名绝经女性确诊患有子宫内膜癌。
该项研究结果表明：罹患子宫内膜癌的风险与总异黄酮摄入量、大豆摄入量、染料木素的摄入量呈负相关。那些总异黄酮摄入量≥7.82毫克每1000千卡/天、大豆摄入量≥3.54毫克每1000千卡/天、染料木素摄入量≥3.40毫克每1000千卡/天的女性罹患子宫内膜癌的风险大大降低。同时研究证实子宫内膜癌的风险与豆类食物如大豆、豆腐或是黄豆的摄入量之间没有统计学意义。
研究人员最后下结论称：我们饮食结构中存在含异黄酮的食物或许能防止绝经妇女子宫内膜癌的发生。(生物谷 Bioon.com)
doi: 10.1093/jnci/djr475
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Legume, Soy, Tofu, and Isoflavone Intake and Endometrial Cancer Risk in Postmenopausal Women in the Multiethnic Cohort Study
Nicholas J. Ollberding,Unhee Lim,Lynne R. Wilkens,Veronica Wendy Setiawan,Yurii B. Shvetsov,Brian E. Henderson,Laurence N. Kolonel andMarc T. Goodman
Background Phytochemicals found in soy and other legumes have been speculated to reduce the risk of endometrial cancer; however, inconsistent findings have been reported in the few epidemiological studies conducted to date.
Methods We conducted a prospective analysis of 46027 nonhysterectomized postmenopausal women who were recruited into the Multiethnic Cohort (MEC) Study between August 1993 and August 1996 and provided detailed baseline information on diet and other endometrial cancer risk factors. A total of 489 women diagnosed with incident endometrial cancer were identified through the Surveillance, Epidemiology, and End Results tumor registry linkages during a median follow-up period of 13.6 years. Cox proportional hazards models were used to estimate multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) for endometrial cancer associated with dietary intake of legumes, soy, and tofu, and for total isoflavones and specific isoflavones (daidzein, genistein, or glycitein). Truncated (age 50–89 years) age-adjusted incidence rates were calculated by applying age-specific rates within isoflavone quintiles to the overall MEC population eligible for endometrial cancer. To estimate the percentage of endometrial cancers that may have been prevented by consuming the highest quintile of total isoflavones, the partial population attributable risk percent was calculated.
Results A reduced risk of endometrial cancer was associated with total isoflavone intake (highest vs lowest quintile, ≥7.82 vs <1.59 mg per 1000 kcal/d, RR = 0.66, 95% CI = 0.47 to 0.91), daidzein intake (highest vs lowest quintile, ≥3.54 vs <0.70 mg per 1000 kcal/d, RR = 0.64, 95% CI = 0.46 to 0.90), and genistein intake (highest vs lowest quintile, ≥3.40 vs <0.69 mg per 1000 kcal/d, RR = 0.66, 95% CI = 0.47 to 0.91). No statistically significant association with endometrial cancer risk was observed for increasing intake of legumes, soy, tofu, or glycitein. Truncated age-adjusted incidence rates of endometrial cancer for the highest vs lowest quintile of total isoflavone intake were 55 vs 107 per 100000 women per year, respectively. The partial population attributable risk percent for total isoflavone intake lower than the highest quintile was 26.7% (95% CI = 5.3% to 45.8%).
Conclusion This study suggests that greater consumption of isoflavone-containing foods is associated with a reduced risk of endometrial cancer in this population of nonhysterectomized postmenopausal women.
