Prostate Health

TURMERIC (Curcumin) and Soy; their relationship to Prostate Health

Each year around 3,300 Australian men die of prostate cancer making prostate cancer Australia's second cancer killer among men and this matches the impact of breast cancer on women.

Current therapies for prostate cancer include surgical removal of the prostate, chemotherapy, radiation and/or freezing the tumour however, there are often side-effects including incontinence and impotence (Wang Q, et al. Cancer Research, Dec 2011) Unfortunately success is dependant on a number of factors that include age, early diagnosis and type and progression of the cancer (Loke T. W, et al. BJUI 2011). Solar radiation is a catalyst for vitamin D conversion by humans and is therefore an important factor in dete

There is emerging evidence that changes in lifestyle, diet, the addition of dietary and herbal supplements and environmental factors may contribute to a reduction in the risk of developing prostate cancer and benign prostatic hypertrophy (enlarged prostate). In this issue these influences are discussed.

Following are two dietary changes that may help.

India has one of the lowest rates of breast and prostate cancer - and one of the highest levels of turmeric consumption - in the world. While clearly not proving cause and effect, this inverse relationship between breast and prostate cancer and turmeric consumption is of interest given existing scientific evidence that one particular chemical found in turmeric, curcumin, can prevent cancer cell growth. (Indo American News on September 2, 2011)

Prostate cancer is an uncommon cancer in the developing countries affecting 4-5 men per 100,000 population in India. The rate of prostate cancer per 100,000 population in the US is 85 (20 fold difference versus men living in India)

Curcumin causes a marked decrease in the extent of cell proliferation and a significant increase in the extent of apoptosis and  could be a potentially therapeutic anti-cancer agent, as it significantly inhibits prostate cancer growth, and has the potential to prevent the progression of this cancer to its hormone refractory state. (Dorai T, et al. Prostate. 2001 Jun 1;47(4):293-303)

Also, Curcumin acts as a chemosensitizer and radiosensitizer for tumours and in some cases, curcumin has also been shown to protect normal organs such as liver, kidney, oral mucosa, and heart from chemotherapy and radiotherapy-induced toxicity. (Goel A, et al. Nutr Cancer. 2010;62(7):919-30)

As discuss before there is good evidence that soy isoflavones have a positive effect on the incidence and progression of prostate disease and could and as Indian diets also contain Tufu does the combination of soy and turmeric supplements add to the positive data?

A randomised double-blind study of eighty five men examined the expression of androgen receptor and PSA before and after treatment of isoflavones and/or curcumin.

At the six month follow up, production of PSA was markedly decreased by the combined treatment of isoflavones and curcumin in prostate cancer cell line. The expression of the androgen receptor was also suppressed by the treatment. In clinical trials, PSA levels decreased in the patients supplemented with soy isoflavones and curcumin.

The authors of the study concluded that soy-isoflavones and curcumin could modulate serum PSA levels. Curcumin presumably synergizes with isoflavones to suppress PSA production in prostate cells through the anti-androgen effects. (Ide H, et al. Prostate. 2010 Jul 1;70(10):1127-3

Findings  presented at the Ninth Annual American Association for Cancer Research Frontiers in Cancer Prevention Research Conference  reported that Genistein, a natural chemical found in soy inhibit prostate cancer cells from becoming metastatic and spreading to other parts of the body. So far the cancer therapy drug has worked in preclinical animal studies and now shows benefits in humans with prostate cancer.(News Letter, Northwestern University, November, 2010)

The phytoestrogen biochanin A, found in red clover, significantly reduced tumour size and incidence. Studies indicate that biochanin A inhibits prostate cancer cell growth through induction of cell cycle arrest and apoptosis. Biochanin A-regulated genes suggest multiple pathways of action. Biochanin A inhibits the incidence and growth of LNCaP xenograft tumours in athymic mice (Rice L et al, Prostate 2002 Aug 1;52(3):201-12).

Other studies have confirmed these results; before surgery, 20 men consumed 160 mg/day of red clover-derived dietary isoflavones, containing a mixture of genistein, daidzein, formononetin, and biochanin A. Serum PSA, testosterone, and biochemical factors were measured, and clinical and pathological parameters were recorded.

The incidence of cell death in prostate tumour cells from radical prostatectomy specimens was compared between 18 treated and 18 untreated control tissues. There were no significant differences between pre- and post treatment serum PSA, Gleason score, serum testosterone, or biochemical factors in the treated patients. Apoptosis in radical prostatectomy specimens from treated patients was significantly higher than in control subjects, specifically in regions of low to moderate-grade cancer (Gleason grade 1-3). No adverse events related to the treatment were reported. This report suggests that dietary isoflavones may halt the progression of prostate cancer by inducing apoptosis in low to moderate-grade tumours, potentially contributing to the lower incidence of clinically significant disease.

(Zhau R et al, Cancer Epidemiol Biomarkers Prev. 2002 Dec;11(12):1689-96)..

Soy may also have other anti-cancer actions in addition to the isoflavones. Soy beans contain the substance, Bowman-Birk Protease Inhibitor (BBI). Bowman-Birk inhibitor has demonstrated anticarcinogenic activity in both in vitro and in vivo studies(Prostate. 2002 Feb 1;50(2):125-33) BBI derived from soybeans in traditional Japanese diets might underpin low cancer mortality rates in Japan (Manoj H. et al, Journal of Agricultural and Food Chemistry, 2012; 60 (12): 3135).

This information is for education purposes only and does not replace the advice given by your health care professional.