Prostate cancer is almost unknown in parts of the world where men regularly consume small amounts of just two foods. One of these foods is curry, which is a natural source of the antioxidant curcumin. The other prostate-protective food is soy, which is a natural source of soy isoflavones.

The conclusion from over 200 scientific studies is that curcumin and soy isoflavones can prevent prostate cancer, without need for drastic changes in diet. Taken together, curcumin and soy isoflavones help beat prostate cancer at every stage of its development. Here is an overview of how this cancer-fighting duo helps keep men free of prostate cancer.

Curcumin and Soy Isoflavones Prevent Hormonal Stimulation of Prostate Cancer

Prostate problems in general are caused by excessive growth of prostate tissue. The prostate is only about the size of a walnut, a rounded gland about 2-3 cm across, but the entire production of urine by a man’s body has to pass through it. If the lining of the prostate begins to thicken, flow is impeded. The same hormones, testosterone and the hormones broken down from it, fuel the growth of the prostate in both benign prostatic hypertrophy (enlarged prostate) and prostate cancer.

Both curcumin and soy isoflavones counteract the effects of testosterone in the prostate. Curcumin “turns off” the genes that operate androgen receptors in the prostate. This makes them less sensitive to male hormones.

This effect also counteracts the production of prostate-specific antigen (PSA). Every man at risk for prostate cancer is assessed for PSA. Men know that high PSA is bad, but they usually don’t know why.

PSA which is more than just something doctors measure to detect prostate cancer. PSA “peels off” sperm from the sticky proteins in semen so they can swim to the egg after ejaculation. PSA is highly irritating to other tissues, and it helps prostate cancer cells spread through healthy tissue.

Curcumin and Soy Isoflavones Activate the Process of Apoptosis in Prostate Cancer

In prostate cancer, curcumin activates a process known as apoptosis, or programmed cellular suicide. Prostate cells have a genetic fail-safe mechanism that instructs the cell to end its life cycle when DNA is damaged in ways that cause the cell to become a cancer cell. Curcumin accelerates the process of apoptosis when the prostate is exposed to carcinogenic chemicals, when it is exposed to high hormone levels, and when DNA is damaged.

Curcumin also counteracts proteins that cancer cells can generate to escape this process of cell suicide. Curcumin and soy isoflavones have a greater effect than either alone.

Curcumin and Soy Isoflavones Counteract Tumorigenesis

Tumorigenesis is the process through which individual cancer cells aggregate to form tumors. Both curcumin and soy isoflavones counteract this process in different ways.

Curcumin counteracts an enzyme called phosphatidylinositol 3-kinase. This enzyme helps prostate cancer cells become motile, helping them to dislodge from their place in healthy tissue and coalesce with other cancer cells into a tumor.

Curcumin also counteracts the effects of insulin on cancer cell motility, partially helping offset the effects of a high-sugar diet. Soy isoflavones work with curcumin prevent the activation of two cell motility proteins called p38 MAPK and p38 FAK, also keeping cancer cells isolated and relatively harmless.

Curcumin and Soy Isoflavones Interrupt the Cancer Cell Life Cycle

Cancer cells go through a series of steps to replicate their DNA and divide into two new cells. One of those steps is known as the G2/M checkpoint. The original cancer cell stops to “inspect” its DNA, not dividing into two new cells until it generates signals that the DNA was copied correctly. One of the most important soy isoflavones, genistein, keeps cancer cells from “verifying” their DNA so they do not divide. Curcumin amplifies this effect.

Genistein also activates a gene called p21, which instructs the nearly-divided cell to complete its life cycle without creating a replacement cell, in another form of “cell suicide. ”

Curcumin and Soy Isoflavones Stop Inflammation

Men who have a history of prostate inflammation (prostatitis) are at increased risk for prostate cancer. Prostate cancer tumors use inflammation to destroy surrounding healthy tissue so they can build their own blood supplies and then send individual prostate cancer cells into the bloodstream.

Prostate cancer cells can generate hydrogen peroxide and hypochloric acid to eat away at surrounding tissue.

Both curcumin and soy isoflavones block the production of a complex of inflammatory chemicals known as NF-kappaB. Stopping NF-kappaB doesn’t kill cancer cells, but it does prevent them from moving into healthy tissue by the release of inflammation.

Curcumin and Soy Isoflavones Are Potent Antioxidants

Both curcumin and soy isoflavones are potent antioxidants, or, more accurately, they enable the prostate to make its own potent antioxidants and use them to protect healthy DNA. Soy isoflavones induce the production of an antioxidant known as glutathione peroxidase. Curcumin activates an enzyme called glutathione-S-transferase that helps glutathione peroxidase do its work.

How Do We Know Curcumin and Soy Isoflavones Work?

Both curcumin and soy isoflavones have been clinically tested in the treatment of men who have PSA levels suggestive of the early stages of prostate cancer. In a study conducted at the Tokyo University School of Medicine, taking just 40 mg of soy isoflavones and 100 mg of curcumin per day lowered PSA levels in men whose initial PSA levels were over 10 ng/ml. Taking 60 mg of soy isoflavones per day also lowered PSA levels in men whose initial lab values were as low as 2. 5 ng/ml. When curcumin is used by itself, significant results require about 1,500 mg a per day.

That is why for prostate cancer prevention, and for extending remission from prostate cancer, it is best to use curcumin and soy isoflavones together. It is essential that your soy isoflavone product contain at least genistein, and it is better if it lists daidzein and glycetein. (Almost all soy isoflavone products do. )

It is also possible to get some isoflavones from soy foods, but a man’s body can only process the soy isoflavones from a maximum of 15 grams (half an ounce) of tofu, miso, or edamame daily. Eating more than amount won’t help. There is about 80 mg of curcumin in a serving of curry, but since the recommended dosage is greater than 80 mg, it is best to take a curcumin supplement for health and to eat curry, if you like it, for taste.

Some Men Especially Benefit from Curcumin and Soy Isoflavones

Some men especially benefit from taking curcumin and soy isoflavones for prostate health. Men who have type 2 diabetes especially benefit from the combination, since it counteracts growth factors for prostate cancer that are activated by insulin.

Curcumin and isoflavones also are helpful for men who take supplemental testosterone. It used to be thought that testosterone was always detrimental in prostate cancer. Recent research has shown that avoiding low testosterone is actually a must in fighting prostate cancer.

Prostate cancer is more likely in men who have too much testosterone, but it is also more likely in men who have too little. The reason testosterone deficiency increases the risk of prostate cancer is that testosterone itself activates a process called DNA Damage Repair, or DDR. When a man does not have enough testosterone, the proliferation of prostate cancer cells becomes more likely because of the absence of DDR.

Curcumin and soy isoflavones likewise activate DDR, but they can’t do the things that testosterone can do, such as stimulating libido and enhancing erections. When a man wants hormonal help for these problems, testosterone replacement is a must, and curcumin and soy make it safe.

Isn’t Soy a Source of Estrogen?

A common question about soy isoflavones is, aren’t they a form of estrogen? Soy isoflavones are in fact chemically similar to estrogen, but it is almost impossible for a man’s body to absorb enough soy isoflavones that any kind of feminizing effect could occur. Soy isoflavones actually do cause feminine characteristics in male lab rats, but their bodies can absorb relatively more of the substance than male humans. It is not possible for men to overdose on soy isoflavones, but it doesn’t do any good to take more than 60 mg per day, either.

What If I’m Already Getting Advanced Medical Care for Prostate Cancer?

Curcumin and soy isoflavones are completely compatible with conventional medical treatment of prostate cancer. Some research even shows that curcumin increases the susceptibility of this kind of cancer cell to treatment with chemotherapy or radiation. Taking curcumin or soy isoflavones, however, does not mean it is absolutely safe to stop medically directed therapy, since a small minority of men cannot metabolize the two natural plant chemicals.

References:

Gorgoulis VG, Vassiliou LV, Karakaidos P, Zacharatos P, Kotsinas A, Liloglou T, et al. Activation of the DNA damage checkpoint and genomic instability in human precancerous lesions. Nature. 2005; 434: 907–913.

Hour TC, Chen J, Huang CY, Guan JY, Lu SH, Pu YS. Curcumin enhances cytotoxicity of chemotherapeutic agents in prostate cancer cells by inducing p21(WAF1/CIP1) and C/EBPbeta expressions and suppressing NF-kappaB activation. Prostate. 2002; 51: 211–218.

Ide H, Tokiwa S, Sakamaki K, Nishio K, Isotani S, Muto S, et al. Combined inhibitory effects of soy isoflavones and curcumin on the production of prostate-specific antigen. Prostate. 2010; 70: 1127–1133.

Khan N, Adhami VM, Mukhtar H. Apoptosis by dietary agents for prevention and treatment of prostate cancer. Endocr Relat Cancer. 2010; 17: R39–R52.

Messina M. Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence. Fertil Steril. 2010 May 1; 93(7): 2095-104. doi: 10. 1016/j. fertnstert. 2010. 03. 002. Epub 2010 Apr 8.

Nagata Y, Sonoda T, Mori M, Miyanaga N, Okumura K, Goto K, et al. Dietary isoflavones may protect against prostate cancer in Japanese men. J Nutr. 2007; 137: 1974–1979.

Sandur SK, Pandey MK, Sung B, Ahn KS, Murakami A, Sethi G, et al. Curcumin, demethoxycurcumin, bisdemethoxycurcumin, tetrahydrocurcumin and turmerones differentially regulate anti-inflammatory and anti-proliferative responses through a ROS-independent mechanism. Carcinogenesis. 2007; 28: 1765–1773.