Life Extension Magazine February 2007
Eating Your Way to Prostate Cancer
By William Faloon
Cancer cells lurk in the prostate glands of most aging men, yet only one in six men is ever diagnosed with prostate cancer.1 If one looks at what is required for a single cancer cell to develop into a detectable tumor, it becomes obvious that natural barriers exist to protect people against full-blown cancer.
Unfortunately, the dietary choices of most men living in the modern Western world circumvent the body’s natural protective barriers. The end result is that we unwittingly provide biological fuel for existing prostate cancer cells to propagate and metastasize.
Good news: If you understand the biological roles of diet and specific nutrients, you’ll be able to achieve a considerable amount of control over whether isolated cancer cells in your prostate gland will ever show up as a clinically diagnosed disease.
So keep reading, because what you learn here can make a difference between bad news and good news in your future.
The impact of the food we ingest on cell growth and death is so pronounced that it can be identical to the effects displayed by anti-cancer drugs. Unlike synthetic drugs, however, the proper dietary constituents produce no side effects and confer additional health benefits.
All cancers begin when genes that regulate cellular proliferation become so damaged that they can no longer control normal cell division. For example, scientists are actively engaged in clinical research using selenium because it helps protect specific genes that enable cells to divide normally.2-5 The limitation of a nutrient like selenium, however, is that it may not be able to reverse accumulated damage (mutations) to such cell-regulating genes.
Prostate cell genes are especially prone to mutations early in the course of human life. This has been demonstrated by autopsy findings of prostate cancer cells in younger men who never knew they had the disease.6
Doctors continue to wonder why so many men with active cancer cells in their prostate glands do not progress to overt disease. One answer may relate to the discovery of a particular enzyme that prostate cancer cells use to propagate, infiltrate, and metastasize. A large volume of published research indicates that this enzyme functions via multiple pathological pathways to facilitate prostate cancer at various stages.7-21 The encouraging news is that this enzyme can be suppressed via dietary modification and the use of dietary supplements, many of which are already being utilized by health-conscious men today.
Omega 3 Fatty Acids: The First Line of Defense
Diets high in omega-6 fats and saturated fats are associated with greater prostate cancer risk, whereas increased intake of omega-3 fats from fish has been shown to reduce risk.22-29 Based on consistent epidemiological findings across a wide range of human populations, scientists have sought to understand why eating the wrong kinds of fat (saturated and omega-6 fats) provokes a stimulatory effect on prostate cancer.
To ascertain what happens after we eat bad fats, all one has to do is look at the metabolic breakdown pathways that these fats follow in the body, as shown in the chart on the right (Figure 1). For example, let us assume that for dinner, you eat a steak (a source of saturated fat) and a salad, along with a typical salad dressing of soybean and/or safflower oils (sources of omega-6 fats).
As can be seen in Figure 1, both saturated and omega-6 fats convert to arachidonic acid in the body, whereas the meat itself contains arachidonic acid. One way that the body rids itself of excess arachidonic acid is by producing a dangerous enzyme called 5-lipoxygenase (5-LOX). New studies show conclusively that 5-LOX directly stimulates prostate cancer cell proliferation via several well-defined mechanisms.2,26,30-36 In addition, arachidonic acid is metabolized by 5-LOX to 5-HETE, a potent survival factor that prostate cancer cells utilize to escape destruction.31,37-40
Figure 1 clearly demonstrates how consuming a diet of foods rich in arachidonic acid directly provokes the production of the dangerous 5-LOX enzyme, which can promote the progression of prostate cancer. In addition to 5-HETE, 5-LOX also metabolizes arachidonic acid to leukotriene B4, a potent pro-inflammatory agent that causes destructive reactions throughout the body and inflicts severe damage to the arterial wall.41-47
One reason that fish oil supplements have become so popular is that their beneficial EPA/DHA fatty acids can help reduce production of arachidonic acid in the body. As shown in Figure 1, if arachidonic acid levels are reduced, there would be a corresponding suppression of 5-LOX, 5-HETE, and leukotriene B4.
Once one understands the lethal 5-lipoxygenase (5-LOX) cascades, it is easy to see why people who excessively consume foods rich in arachidonic acid, and those who do not reduce the production of excessive arachidonic acid metabolites, are setting themselves up for prostate cancer and a host of inflammatory diseases (including atherosclerosis).2,30,35,48,49
5-LOX Is Over-expressed in Prostate Cancer
Based on studies showing that consumption of foods rich in arachidonic acid is greatest in regions with high incidences of prostate cancer,26,30,35,49 scientists sought to determine how much of the 5-LOX enzyme is present in malignant versus benign prostate tissues.
Using biopsy samples taken from living human patients, the researchers found that 5-LOX levels were an astounding six-fold greater in malignant prostate tissues compared to benign tissues. This study also found that levels of 5-HETE (a 5-LOX metabolite that prevents prostate cancer destruction) were 2.2-fold greater in malignant versus benign prostate tissues.33
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.
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 cancer cell proliferating factors produced in the body. When 5-LOX levels were reduced, the cancer cell stimulatory effect of EGF and other growth factors was diminished.30
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 were shown to reduce tumor angiogenesis along with a host of other growth factors.50 In both androgen-dependent and androgen-independent human prostate cancer cell lines, the inhibition of 5-lipoxygenase (5-LOX) has consistently been shown to induce rapid and massive apoptosis (cancer cell destruction).26,49,51-54
Nutrients That Suppress 5-LOX
Health-conscious people already take nutrients like fish oil that help to lower 5-LOX activity in the body.20,21 Studies show that lycopene and saw palmetto extract also help to suppress 5-LOX.51,55-68 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. For maturing males, the result of excess 5-LOX may be the epidemic of prostate cancer observed after the age of 60.
Based on the cumulative knowledge that 5-LOX can promote the invasion and metastasis of prostate cancer cells, it would appear advantageous to take aggressive steps to suppress this lethal enzyme. The good news is that a natural 5-lipoxygenase (5-LOX) inhibitor is now available and has been added to a popular formula used to maintain healthy prostate function.
In addition to potentially suppressing prostate cancer, the successful inhibition of 5-LOX should also slow the progression of atherosclerosis.