Soy, Curcumin & Prostate Cancer Risk
Because chronic inflammation within the prostate gland is through to be an important risk factor for prostate cancer, anti-inflammatory dietary supplements and medications may be able to reduce the risk of prostate cancer by reducing inflammation.
Isoflavones from soy-based foods are known to act as a weak form of estrogen (the dominant female sex hormone). Based upon this estrogen-like behavior, as well as potential anti-inflammatory properties, soy isoflavones are being studied as possible prevention and treatment agents for prostate cancer, and other types of cancer.
Curcumin, which is present in the Indian curry spice turmeric, is also known to have potent anti-inflammatory properties, and has also been the subject of considerable cancer prevention and cancer treatment research.
A newly published prospective, randomized, blinded, placebo-controlled research study, published in the current issue of the journal Prostate, suggests that the combination of soy isoflavones and curcumin may have important potential prostate cancer prevention properties.
In the first part of thisstudy, human prostate cancer cells were treated with a combination of soy isoflavones and curcumin. Treatment of these human cancer cells with soy isoflavones and curcumin resulted in a significant reduction of prostate-specific antigen (PSA) production by these malignant cells (PSA is a marker of both prostate gland inflammation and prostate gland cancer).
As regular readers of this column are already aware, treatments performed in the laboratory that have beneficial effects on cancer cells, or on mice or rats, do not always have the same positive effects on living, breathing human beings. Therefore, the findings of the second part of this study are of particular interest. A total of 85 men with elevated PSA levels, but without prostate cancer (as confirmed by prostate biopsy), were enrolled in the second phase of this intriguing small study. These 85 men were divided into two groups, and one group received daily supplements containing both soy isoflavones and curcumin, while the second (control) group of men received placebo (sugar) pills that were identical in appearance to the supplement pills (neither the 85 men, nor the nurses who dispensed the supplement pills and placebo pills, were aware of which pills each study volunteer was receiving until after the research study had been completed).
PSA blood levels were tested at the beginning of the clinical portion of this study, and once again 6 months later. As was observed in the prostate cancer cells during the first part of this study, men with a PSA level of 10, or higher, experienced a significant reduction in their blood PSA levels 6 months after starting daily supplementation with soy isoflavones and curcumin.
Although this brief study cannot definitively confirm that soy isoflavone and curcumin supplements reduce the risk of prostate cancer, their ability to reduce elevated PSA levels in men with chronic prostate inflammation, but without evidence of prostate cancer, at least suggests a potential role in the prevention of prostate cancer (presumably through a reduction in prostate gland inflammation).
While there are multiple human research studies underway that are evaluating the effectiveness of soy isoflavones as cancer prevention agents, currently, there are no major human studies looking at the effects of curcumin on prostate cancer risk. Based upon the findings of this small, interesting study of soy isoflavones and curcumin, which suggest a potential additive effect on PSA reduction when both of these dietary supplements are taken together, human research trials should be developed to look at the long-term impact, if any, of combined soy isoflavone and curcumin supplementation on prostate cancer risk.
For additional research information on soy isoflavones and curcumin in cancer prevention and cancer treatment, please review the following previous columns:
Soy Foods & Stomach Cancer Risk
Cruciferous Vegetables, Soy & Breast Cancer Risk
Soy Isoflavones & Recurrent Prostate Cancer
Soy Isoflavones Decrease Breast Cancer Recurrence Risk
Genistein (Soy Isoflavone) & Prostate Cancer
Diet, Soy & Breast Cancer Risk
To learn more about the role of soy isoflavones and curcumin in the prevention of cancer, look for the publication of my new landmark book, “A Cancer Prevention Guide for the Human Race,” in the summer of this year.
I and the staff of Weekly Health Update would again like to take this opportunity to thank the more than 100,000 new and returning readers who visit our premier global health information website every month. As always, we enjoy receiving your stimulating feedback and questions, and I will continue to try and personally answer as many of your inquiries as I possibly can.
Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, professor of surgery, cancer researcher, oncology consultant, and a widely published author.
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Cancer surgeon, professor of surgery & author. Webmaster: http://doctorwascher.com | More from Robert A. Wascher, MD, FACS

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Most soy is bad for you, although fermented soy such as miso or natto are good for you.
Is there any reason to believe there would be a benefit from soy+curcumin for men diagnosed with PCa on androgen blockade, 5a-reductase inhibitor, or anti-antrogen (since soy+curcumin may operate by suppressing the androgen receptor)?