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Life Extension Magazine December 2013

Impact of Diet on Prostate Cancer Risk and Mortality

By William Faloon

5-LOX Is Over-Expressed in Prostate Cancer

Based on studies showing that consumption of foods rich in omega 6 fatty acids is associated with higher incidences of prostate cancer, scientists sought to determine how much of the 5-LOX enzyme is present in malignant versus benign prostate tissues.25

Using biopsy samples taken from living human patients, the researchers found that 5-LOX mRNA levels were an astounding six-fold greater in malignant prostate tissues compared with benign tissues. This study also found that levels of 5-HETE were 2.2-fold greater in malignant versus benign prostate tissues.26 The scientists concluded this study by stating that selective inhibitors of 5-LOX may be useful in the prevention or treatment of patients with prostate cancer.26

5-LOX Promotes Tumor Growth Factors

As the evidence mounts that ingesting “bad fats” increases prostate cancer risk, scientists are evaluating the effects of 5-LOX on various growth factors involved in the progression, angiogenesis, and metastasis of cancer cells.

One study found that 5-LOX activity is required to stimulate prostate cancer cell growth by epidermal growth factor (EGF) and other tumor cell proliferating factors produced in the body.19 When 5-LOX levels were reduced, the cancer cell stimulatory effect of EGF and other growth factors was diminished.19

In a mouse study, an increase in 5-LOX resulted in a corresponding increase in vascular endothelial growth factor (VEGF), a key growth factor that tumor cells use to stimulate new blood vessel formation (angiogenesis) into the tumor. 5-LOX inhibitors have been shown to reduce tumor angiogenesis along with a host of other growth factors.27

In both androgen-dependent and androgen-independent human prostate cancer cell lines, the inhibition of 5-LOX has consistently been shown to halt the growth stimulatory action of 5-LOX and prompt rapid and massive apoptosis (cancer cell destruction).20,22,28,29

Arachidonic Acid’s Destructive Cascade

Omega-3 Fatty Acids: A First Line of Defense

One reason that fish oil supplements have become so popular is that their beneficial EPA/DHA fatty acids can help reduce the production of arachidonic acid-derived tumor promoting byproducts in the body.30-33 As shown on the flow chart above (Figure 2), if arachidonic acid levels are reduced, there would be a corresponding suppression of 5-LOX and its metabolic byproducts 5-HETE and leukotriene B4.

Once one understands the lethal 5-LOX cascades, it is easy to see why people who excessively consume foods rich in arachidonic acid, and those who fail to reduce the production of arachidonic acid metabolites (such as 5-HETE) by ensuring adequate intake of omega-3 fatty acids, are setting themselves up for prostate cancer and a host of inflammatory disorders (including atherosclerosis).

Nutrients That Suppress 5-LOX

Health-conscious people already take nutrients like curcumin and fish oil that help to lower 5-LOX activity in the body.34,35 Studies show that lycopene and saw palmetto extract also help to suppress 5-LOX.36,37 The suppression of 5-LOX by these nutrients may partially account for their favorable effects on the prostate gland.

As humans age, however, chronic inflammatory processes can cause the over-expression of 5-LOX in the body.38 For maturing males, the result of excess 5-LOX may be the epidemic of prostate cancer observed as men age.2

Based on the cumulative knowledge that 5-LOX itself and its metabolic products can promote the progression and metastasis of prostate cancer cells, it would appear advantageous to take aggressive steps to suppress this lethal enzyme.36

This can be done by avoiding foods that promote 5-LOX formation in the body and taking supplements that inhibit 5-LOX via differing pathways.

Multiple Dangers of Excess Arachidonic Acid
Multiple Dangers of Excess Arachidonic Acid

In response to arachidonic acid overload, the body increases its production of enzymes like 5-lipoxygenase (5-LOX) to degrade arachidonic acid.48 Not only do 5-LOX products directly stimulate cancer cells propagation, but the breakdown products that 5-LOX produces from arachidonic acid (such as leukotriene B4, 5-HETE, and hydroxylated fatty acids) cause tissue destruction, chronic inflammation, and increased resistance of tumor cells to apoptosis (programmed cell destruction).19-21,48-58

It is important to understand that 5-LOX is not the only dangerous enzyme the body produces to break down arachidonic acid. As can be seen in the chart on the previous page, both cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) also participate in the degradation of arachidonic acid.

COX-1 causes production of thromboxane A2, which can promote abnormal arterial blood clotting (thrombosis), resulting in heart attack and stroke.59-63 Thromboxane A2 is also involved in tumor metastasis.64,65 COX-2 is directly involved in cancer cell propagation, while its breakdown product (prostaglandin E2) promotes chronic inflammation.56,66-68 Most health-conscious people already inhibit the COX-1 and COX-2 enzymes by taking low-dose aspirin, curcumin, green tea, and various plant flavonoids such as pomegranate.61,69-82

A more integrative approach to this problem, however, would be to also reduce dietary levels of arachidonic acid, which is the precursor of 5-HETE and leukotriene B4.83

Research Substantiating Boswellia

Specific extracts from the boswellia plant selectively inhibit 5-lipoxygenase (5-LOX), a potent inducer of inflammation and carcinogenic byproducts.39,40

Boswellia extracts have been used for centuries, particularly in India as anti-inflammatory agents.41 In several well-controlled human studies, boswellia has been shown to be effective in alleviating various chronic inflammatory disorders.42-46

Scientists have discovered that the specific constituent in boswellia responsible for suppressing 5-LOX is AKBA ( 3-O-acetyl-11-keto-B-boswellic acid).41 Boswellia-derived AKBA binds directly to 5-LOX and inhibits its activity.41 Other boswellic acids only partially and incompletely inhibit 5-LOX.41,47

Formulas containing high concentrations of AKBA from boswellia have been developed based on its ability to treat inflammatory disorders. Standardized boswellia extracts have long been included in prostate support nutrient formulas for the purpose of suppressing excess 5-LOX.

Prostate-Protecting Properties of Boswellia

Tumor necrosis factor-alpha (TNF-alpha) is a pro-inflammatory cytokine that often increases in aging people.84

From the standpoint of keeping prostate cancer cells in check, boswellia has been shown to prevent the TNF-alpha-induced expression of a protein-degrading enzyme called matrix metalloproteinase (MMP).85 Cancer cells use the MMP enzyme to tear apart natural barriers in the body that would normally encase them.86 Prostate cancer cells are notorious for inducing the production of this enzyme (TNF-alpha) that causes containment structures within the prostate gland to vanish, thus enabling the cancerous prostate cells to break through healthy prostate tissue and eventually metastasize.87,88

Prostate cancer cells use adhesion molecules (known as VCAM-1 and ICAM-1) to facilitate their spread throughout the body. Boswellia has been shown to prevent the up-regulation of these adhesion molecules, which are directly involved in inflammatory processes.85 Chronic inflammation is tightly linked to the induction of aberrant angiogenesis used by cancer cells to facilitate the growth of new blood vessels (angiogenesis) into tumors.89

The potent 5-LOX-inhibiting properties of boswellia, and its ability to suppress other inflammatory factors such as TNF-alpha, make it an important nutrient for those concerned with prostate cancer.41,85

Tea, Soy, Lignans, and Cruciferous Vegetables
Tea, Soy, Lignans, and Cruciferous Vegetables

Men who regularly consume certain plant foods have sharply lower rates of prostate cancer.90 Studies show that cauliflower, broccoli, flax lignans, and soy isoflavones protect against a host of diseases, including prostate cancer.91-99

A 2013 study reported that soy food consumption, more popular in Asian populations, is associated with a 25 to 30% reduced risk of prostate cancer.100 There is a lot of confusion about soy in the alternative health community. Everyone agrees that limiting intake of soybean oil is important because it is loaded with omega-6 fats.13 Other constituents found in soy, however, such as genistein and daidzein have demonstrated anti-prostate cancer mechanisms.101-107

Polyphenols found in green tea decrease serum levels of PSA, hepatocyte growth factor, and vascular endothelial growth factor (VEGF) in prostate cancer patients.108-113

The FDA says, however, that there is insufficient evidence to claim that green tea consumption protects against prostate cancer.114 Life Extension issued a rebuttal to the FDA position on green tea and prostate cancer in the November 2005 edition of Life Extension magazine®.

Urgent Need to Alter Dietary Patterns

Those consuming Western diets predispose themselves to cancer.3 It is encouraging that we know what food groups increase prostate cancer risk and what foods/nutrients reduce it.

All aging men should shift their diet towards foods that protect against prostate cancer. Those with rising or elevated PSA should be especially diligent in avoiding dietary factors that can fuel the growth of prostate tumors.115

The lethal impact of cancer-promoting foods may be mitigated by taking supplements such as green tea, curcumin, fish oil, pomegranate, and boswellia, along with regular inclusion of cruciferous vegetables and other healthy foods in one’s diet.

If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.