Judged by the currently known facts of nutritional sciences a clear health benefit has to be concluded from an increased dietary intake of soy isoflavones (Tseng et al. 2008). This conclusion is supported by epidemiological data. The value of data from epidemiological studies has been questioned: Such studies do not yield the same robust results as controlled trials. In fact epidemiological data must be carefully interpreted. They do, however, add to the overall evidence on safety and efficacy, and cannot be neglected for formal reasons.

Soy food and the isoflavones contained therein have been subject to studies in far more than 400,000 women, with an excellent safety profile derived from these studies. Epidemiological studies have dealt with questions of health related effects of isoflavone-containing preparations, as well as with questions related to safety. Studies cover (among other topics) the effects of isoflavones

• Against menopausal disorders;
• On bone mineral density;
• On cardiovascular health;
• In the prevention of breast cancer;
• In the prevention of endometrial cancer; and
• In the prevention of prostate cancer.

References

Tseng, M., Olufade, T., Kurzer, M. S., Wahala, K., Fang, C. Y., van der Schouw, Y. T., and Daly, M. B. (2008). Food frequency questionnaires and overnight urines are valid indicators of daidzein and genistein intake in U.S. women relative to multiple 24-h urine samples. Nutr. Cancer 60 (5): 619-626.