Written by Greg Arnold, DC, CSCS.  In postmenopausal women , those in the highest 20% of soy isoflavone intake had a 34% reduced risk of uterine cancer compared to those in the lowest 20% of total isoflavone intake. 

Endometrial cancer forms in the tissue lining the uterus and most commonly occurs in cells that make and release mucus and other fluids (called an “adenocarcinoma”). The National Cancer Institute estimates there will be 43,470 new cases of endometrial cancer and 7,950 deaths in 2010 (1). The number one risk for endometrial cancer is elevated levels of estrogen (2) while a close second is obesity, known to increase risk by 300-500% (3, 4). Endometrial cancer costs our healthcare system $790 million each year (5).

A new study (7) has suggested that foods containing soy isoflavones may be a benefit. In the study, researchers analyzed records of 46, 027 postmenopausal women between the ages of 50 and 89 (who had not undergone a hysterectomy) participating in the Multiethnic Cohort Study between August 1993 and August 1996 (8). Patients provided information through a number of questionnaires (9) to examine diet and lifestyle information, with a specific focus on soy isoflavone intake.

Over the course of the study, 489 women were diagnosed with endometrial cancer. The researchers found that those in the highest 20% of soy isoflavone intake had a 34% reduced risk of endometrial cancer compared to those in the lowest 20% of total isoflavone intake (≥ 7.82 vs. < 1.59 milligrams per 1000 calories of food per day). When they looked at specific isoflavones, those with the highest 20% of daidzein intake had a 36% reduced risk compared to the lowest 20% (≥3.54 vs. < 0.70 mg per 1000 cal/d) while those in the highest 20% of genistein intake had a 34% reduced risk (, ≥ 3.40 vs. < 0.69 mg per 1000 kcal/d).

For the researchers, “This study suggests that greater consumption of isoflavone-containing foods is associated with a reduced risk of endometrial cancer in this population of postmenopausal women [without a hysterectomy].”

Source: Ollberding, Nicholas J., et al. “Legume, soy, tofu, and isoflavone intake and endometrial cancer risk in postmenopausal women in the multiethnic cohort study.” Journal of the National Cancer Institute 104.1 (2012): 67-76.

© The Author 2011. Published by Oxford University Press.

Posted January 17, 2012.


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  5. “The Economic Costs of Obesity” – posted on the West Virginia Department of Health and Human Resources.
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  7. Ollberding NJ.  Legume, Soy, Tofu, and Isoflavone Intake and Endometrial Cancer Risk in Postmenopausal Women in the Multiethnic Cohort Study .  Jou Nat Cancer Inst 2011; 104(1): 67-76.
  8. Multiethnic Cohort Study Website.
  9. MEC Questionnaires – posted on the Multiethnic Cohort Study website.