A Natural Arsenal for Prostate Cancer Prevention
By Michael Downey
A remarkable new study has validated a method to slow prostate cancer progression that was long ago recommended to Life Extension members.
What made this study even more noteworthy is where it was presented.
The annual gathering of the American Society of Clinical Oncology (ASCO) is considered the world’s most prestigious cancer forum. More than 25,000 oncology experts attend this meeting, and the media eagerly reports on meaningful advances in cancer prevention and treatment.
At the 2013 ASCO meeting, findings from a study were released that underscored how effective certain natural compounds can be as a prostate cancer therapy.
In this placebo-controlled, double-blind trial of treatment-refractory prostate cancer patients, a four-nutrient supplement resulted in a 63.8% median reduction in the increase of PSA levels.1 The PSA marker is used by oncologists to determine progression or regression of prostate cancer, and to evaluate whether treatments are working or failing.
In the study presented at ASCO, patients with a PSA relapse after radiotherapy or surgery for localized prostate cancer took two daily capsules containing pomegranate seed, broccoli, green tea, and turmeric. Over a six-month period, median PSA levels increased only 14.7% in the supplement group—compared to 78.5% in the placebo group!1 PSA levels remained stable, or below, baseline values for a compelling 46% of the supplement patients—but for only 14% of the placebo patients.
Prostate cancer is the most common malignancy in US men (excluding non-melanoma skin cancer),2 affecting one male in every six.3 Autopsy findings show a significant percentage of men have underlying prostate cancer without even knowing it.4-6
This article will present evidence about the prostate cancer preventing effects of a wide range of nutrients. What makes this topic so compelling are the recent findings presented at ASCO showing that pomegranate seed, green tea, broccoli, and turmeric (source of curcumin) were so effective in prostate cancer patients.1 The implication is that these nutrients may also afford considerable protection against prostate cancer progression.
A comprehensive defense against prostate cancer involves healthy diet, supplemental nutrients, hormone balance, and annual PSA screening. The foods and nutrients described herein have been documented in published studies to target prostate cancer and help prevent or attenuate its development. As a bonus, they also confer huge protection against other age-related disorders.
Since there are overlapping mechanisms of action amongst many of these foods/nutrients, it may not be necessary to take every one of them. Most impressive, however, is the voluminous amount of scientific evidence that substantiates the anti-cancer properties of these nutrients. Yet mainstream medicine remains largely in the dark.
Nutrients for Prostate Cancer Prevention
Flaxseeds provide a rich supply of lignans and essential fatty acids that promote prostate health. The lignans in flaxseed are believed to offer protection against chronic disease and cancer, including hormone-dependent malignancies.7-9
A large study demonstrated that men with higher enterolactone levels were up to 72% less likely to have prostate cancer than those with the lowest levels.10 Studies have confirmed that flaxseed supplementation lowers PSA levels, and significantly reduces the proliferation of normal prostate cells and prostate cancer cells.9,11 A pilot study on men who were scheduled to have a repeat prostate biopsy found that supplementation with flaxseeds, as part of a low-fat diet, lowered levels of PSA and prostate cell proliferation.9
Research has shown that boron can reduce the risk of prostate cancer.12 In one study, men with the highest boron intake showed a 54% lower risk of prostate cancer compared to those with the least intake.13
In a validated animal model of prostate cancer, researchers found that oral administration of various concentrations of a boron-containing solution led to 25-38% decreases in tumor size, and 86-89% reductions in PSA levels.14 The suggestion that supplemental boron may help to shrink prostate tumors while also decreasing levels of PSA is exciting. That’s because PSA—in addition to being an important prostate cancer marker—may itself be a contributor to prostate cancer promotion.15
Boron compounds inhibit the activity of prostate-specific antigen (PSA).14 Higher boron levels in the blood lower the risk of prostate cancer by reducing intracellular calcium signals and storage.16 At normal concentrations, boron operates selectively—inhibiting prostate cancer cell proliferation while allowing normal prostate cells to grow.17
The typical daily intake range for boron is 1-8 milligrams daily, however individuals living in boron rich environments may consume far greater than this amount.18 If lab studies can be replicated in human patients, higher daily dosages may become an effective and low-cost adjuvant therapy. Life Extension® members already obtain boron (3-6 mg) in their supplements.
3. Cruciferous Vegetables
In recently released studies, three phytochemicals derived from cruciferous vegetables (such as broccoli) have shown promise in inhibiting prostate cancer in experimental models.19,20 Because their chemical names are challenging— indole-3-carbinol, 3,3’-diindolylmethane, and phenethyl isothiocyanate—they are better known as I3C, DIM, and PEITC, respectively.
I3C has several different actions that help prevent and inhibit prostate cancer. It helps activate detoxification pathways, prevents cancer cell growth, induces apoptosis, regulates gene expression, protects DNA from damage, and modulates a variety of cell signaling pathways.20-23
DIM has been shown to protect against prostate cancer by inhibiting the phosphorus-transferring enzyme Akt, inhibiting the master DNA-transcription regulator nuclear factor-kappaB (NF-kB)—and blocking the crosstalk between them.24 This is a novel mechanism through which DIM inhibits cell growth and induces apoptosis in prostate cancer cells, but not in non-tumorigenic prostate epithelial cells.24 The ability of DIM to target aberrant epigenetic changes coupled with its ability to promote the detoxification of carcinogens, make it an effective chemopreventive agent as it is able to target multiple stages of prostate carcinogenesis.18
In a study released in May 2013, PEITC was found to suppress a compound known as PCAF (P300/CBP-associated factor)—which in turn inhibits androgen receptor-regulated transcriptional activity in prostate cancer cells.19 Daily suggested dosages are 14 milligrams for DIM, and 80-160 milligrams for I3C. An I3C dosage of 200-600 milligrams daily is suggested as an adjuvant for prostate cancer therapy. Dosages for PEITC are not well-established.
4. Vitamin D
As the New England Journal of Medicine clarified, “Cancer results from the accumulation of mutations in genes that regulate cellular proliferation.”25 In other words, cancer is essentially caused by the genetic mutations that occur over the lifespan. The fascinating impact of vitamin D is that it protects against cancer by enabling us to regain control over the genes that regulate cell proliferation. Vitamin D affects at least 200 human genes.26 These genes are responsible for regulating crucially important aspects of cells: their proliferation, differentiation, and apoptosis.
In recent years, a multitude of studies have shown cancer risk reductions of 50% and greater based on higher vitamin D status.27-30 People with higher vitamin D levels have lower risks of lethal prostate cancer, as well as reduced risks of other cancers.26,27,31-34 Individual blood testing is needed to determine individual-appropriate dosages, which typically range from 2,000 to 10,000 international units (IU) daily for prevention. Life Extension suggests an optimal vitamin D blood level of 50-80 nanograms per milliliter (ng/mL).
5. Soy Isoflavones
Some studies show that the highest intake of soy-based foods correlates with a 42-75% lower risk of prostate cancer.35-38 Early animal studies found that this difference is most likely attributable to soy isoflavones inhibiting prostate tumor growth by acting directly against tumor cells and indirectly against tumor neovasculature (growth of new blood cells).37 Human studies support this evidence.
Japanese scientists took blood samples from over 14,000 men during 1988-1990. Their analysis clearly established that elevated serum levels of all three isoflavones assessed—genistein, daidzein, and equol—imparted strong protective effects against prostate cancer.39 Men with the highest circulating levels of genistein, daidzein, and equol reduced prostate cancer risk by 62%, 59%, and 66%, respectively. Genistein and daidzein are found in soy, and equol is derived from daidzein by bacterial flora in the intestines.39-41 Also, genistein was shown to have “potent anti-proliferative effects” against human prostate cells42 and inhibit metastatic potential of sex gland cancers such as prostate cancer.43 Genistein also blocks an enzyme that destroys an anticancer vitamin D metabolite in cancer cells.44 A suggested dosage of soy isoflavones is 135-270 milligrams daily with food.
6. Green Tea Extract
Laboratory research with cultures has long suggested that green tea catechins, including epigallocatechin-3 gallate (EGCG), may inhibit the growth of cancer cells. Evidence from human studies now demonstrates that green tea compounds can help prevent prostate cancer. A clinical trial demonstrated that green tea catechins were 90% effective in preventing prostate cancer in men with pre-malignant lesions.45 Researchers recruited 60 men, aged 45-75. Thirty participants received 200 milligrams of green tea catechins (50% EGCG) three times daily, while the other 30 subjects received a placebo. Biopsies were conducted at six and 12 months. Remarkably, only one man in the treatment group was diagnosed with prostate cancer, compared to nine men in the control group who developed the disease. No significant side effects or adverse reactions were reported.45 The lead researcher concluded that “90% of chemoprevention efficacy could be obtained by [green tea catechin] administration in men prone to developing prostate cancer.”45
Green tea polyphenols have also shown efficacy as an adjunctive therapy. Prostate cancer patients were given 1,300 milligrams of green tea polyphenols, mostly EGCG, prior to the time of radical prostatectomy. They showed significant reductions in PSA and other tumor promoters such as vascular endothelial growth factor.46 Suggested dosages of EGCG are 300-350 milligrams daily, and adjuvant cancer therapy dosages of EGCG range up to 3,000 milligrams daily . The FDA, however, does not believe there is sufficient evidence to say that green tea reduces prostate cancer risk. A federal judge ruled against the FDA’s attempt to suppress claims that green tea may reduce prostate cancer risk. 47
7. Omega-3 Fatty Acids
In scientific studies, high blood levels of the omega-3 fatty acids DHA and EPA (docosahexaenoic acid and eicosapentaenoic acid, respectively) have been demonstrated to correspond to a lower risk of developing prostate cancer.48 EPA has been shown to suppress the formation of the omega-6 fatty acid arachidonic acid (AA) by inhibiting the enzyme delta-5-desaturase.49 EPA has also been found to contribute to the inhibition of uPA —a substance known as urokinase-type plasminogen activator believed to play a role in prostate cancer invasion and metastasis.50
Although cold water fish such as tuna, sardines, herring, and salmon provide a rich omega-3 source, commercially available pharmaceutical-grade fish oils also deliver large amounts of EPA and DHA.51 Suggested dosages are 2-4 grams of fish oil concentrate supplying 700-1,400 milligrams of EPA and 500-1,000 milligrams of DHA, daily with food. For adjuvant cancer therapy, recommended dosages are 4-8 grams of fish oil concentrate supplying up to 2,800 milligrams of EPA and up to 2,000 milligrams of DHA, daily with food.