To all but the hardest of hard-nosed skeptics, a wide range of nutrient supplements can play an important role in preventing, and even treating, some forms of cancer. So vast is the literature on cancer prevention and nutrient supplementation that a complete run-down of the evidence is well beyond the scope of this medium. What follows, then, is a brief sampler of some recent studies that have examined this relationship.

Curcumin Blocks Breast Cancer Metastasis

No known pharmaceutical drug effectively prevents breast cancer metastasis. However, new research from the M.D. Anderson Cancer Center at the University of Texas in Houston suggests that consuming adequate amounts of the common spice curcumin may halt the spread of breast cancer in its tracks.¹

Curcumin is the primary ingredient in turmeric (Curcuma longa), the spice that gives curry its trademark yellow color and unique flavor. Turmeric has been used for millennia all over South Asia, not just for flavoring foods but also for its medicinal properties. Perhaps not coincidentally, epidemiologic data also suggest a relatively low rate of colon cancer in South Asian countries.²

The new findings on breast cancer metastasis come from a study in mice with breast tumors that were allowed to grow to about 10 mm in diameter (about the size of a pea) before being surgically removed. Most such tumors will have metastasized by the time of the surgery. The mice were then started on a standard diet (control), or one of three experimental diets that included either 1) powdered curcumin; 2) Taxol™ (paclitaxel), a common breast cancer chemotherapy drug; or 3) curcumin + Taxol. Although Taxol (like other chemotherapy agents) normally suppresses breast cancer growth in the short term, extended use is known to paradoxically increase the risk of metastasis.

Breast cancer in mice typically spreads to the lungs. In the mice on the control diet, the researchers later noted metastases visible to the naked eye in 96% of the animals, while Taxol alone produced only a modest reduction in lung metastases. By contrast, in the mice treated with curcumin or curcumin + Taxol, the incidence and number of visible lung metastases was significantly reduced.

While it might be easy to dismiss this admittedly early finding as merely suggestive and not necessarily clinically important (Of course, clinical confirmation would certainly be extremely valuable!), many other studies, both in the laboratory and the clinic, have convincingly demonstrated that curcumin has important and wide-ranging anticancer activity. Curcumin has been shown to suppress the growth of cancer of the colon and rectum,^2-6 prostate,^7-15 breast,^{1, 16-20} lung,^21-24 liver,^{25, 26} stomach,^{27, 28} bladder,²⁹ and ovary.³⁰ Thus, we have every reason to believe that these significant results, though reported only so far in mice, would likely translate to a comparable benefit in humans.

Given curcumin’s lack of toxicity, there would seem to be no reason not to take curcumin supplements (in addition to increasing your curry intake). Although recent studies suggest that doses of 3.6 g to 8 g per day should be effective, these studies were done in people with active cancer or precancerous lesions.

The scientific researchers Durk Pearson & Sandy Shaw suggest that healthy people would do well to take 200 mg per day and to take it in its whole form, as turmeric. They think this is a better idea, because turmeric contains other closely related compounds that are even more effective than curcumin alone. The efficacy of these active compounds ranges from 2-fold to as much as 10- to 15-fold more effective. So while taking curcumin alone as a preventive for cancer (or for Alzheimer’s) may well help, taking the entire turmeric package may work even better, because it contains more powerful antioxidants that have evolved together to work more effectively.

Resveratrol Has Anticancer Effects

Resveratrol, which is the most active of a group of compounds known as grape polyphenols, is found in abundance in the skins of grapes. It is widely thought that resveratrol from grape skins may be at least partly responsible for the “French paradox, whereby Frenchmen, who have a notorious high-fat diet, nevertheless have a low risk of cardiovascular disease.

Growing evidence suggests that resveratrol may protect not only against cardiovascular disease but also against cancer and neurodegenerative disease by acting as an antioxidant, antimutagen, anti-inflammatory, and neuroprotectant. It may also promote longevity by stimulating a gene-silencing mechanism that extends the lifespan of many organisms. Resveratrol’s anticancer effects were first reported in a 1997 study, which showed that it inhibits all three of the major steps in carcinogenesis: 1) initiation, 2) promotion, and 3) progression.³¹ That study spawned a torrent of scientific papers elucidating the cellular and biochemical mechanisms of action of this remarkable compound, which has demonstrated activity against many forms of cancer.³²

Other studies have shown that resveratrol may be a key player in reducing the risk of prostate cancer. First, it inhibits many different stages of the multistage process required for prostate cells to become cancerous. Second, it inhibits the function of androgen receptors (such as testosterone receptors), which are vital to cancer cell growth. And third, it interferes with signaling pathways within cancer cells that are required for them to survive. Together, these features may combine as a powerful force that overpowers cancer cells in the prostate gland.

For those who wish to exploit the potential health benefits of resveratrol in preventing cancer, drinking wine may be an enjoyable way to do so, but it is certainly not the best way. For a consistent, reliable intake of resveratrol in optimal amounts, supplementation is the way to go.

Lycopene: Natural Protection Against Prostate and Breast Cancer

Lycopene is one of those rare nutrients that has earned considerable acceptance from the conventional medical community. You can even find it hyped on ketchup bottles. There is little doubt that lycopene, the carotenoid compound that imparts the red-orange color to foods like tomatoes, carrots, and pumpkins, has important anti-prostate cancer benefits. For example, in a 2001 study,³³ 15 men scheduled to undergo a radical prostatectomy were supplemented with 30 mg of lycopene daily for 3 weeks prior to surgery.

Subsequent analysis of the excised tissue revealed that these men were far less likely to have cancerous cells spread beyond their prostate gland (27% incidence) than men who had received no lycopene supplementation (82% incidence). The lycopene-treated men also had smaller tumors (80% vs. 45% <4 ml), less involvement of surgical margins and/or extraprostatic tissues with cancer (73% vs. 18% organ-confined disease), and less diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia (33% vs. 0% focal involvement). The mean plasma prostate-specific antigen (PSA) levels were also significantly lower in the lycopene-treated group. This finding suggests that lycopene may inhibit the growth and migration of cancerous cells in the prostate.

Less well-documented is lycopene’s role in female breast cancer. Evidence suggests that IGF-1 (insulin-like growth factor 1) may play a role in breast cancer (as well as lung and colorectal cancer in women) by acting as a mitogen (a substance that increases cell proliferation) and by inhibiting apoptosis (programmed cell death). Observational studies show that higher levels of IGF-1 are linked to higher risks of these and possibly other cancers.³⁴ Hence, interfering with IGF-1 signaling, especially if such interference can be localized to high-risk tissues sensitive to its mitogenic effects, would be very desirable in terms of reducing cancer risk.

A recent paper³⁵ reports that, in mammary cancer cells, growth stimulation by IGF-1 was markedly reduced by lycopene treatment. The researchers note that these effects were not associated with changes in the number or affinity of IGF-1 receptors. Rather, they were a result of an increase in membrane-associated IGF-binding proteins, which negatively regulate IGF-1 receptor activation in different cancer cells. Moreover, they report, lycopene inhibited basal and IGF-induced thymidine incorporation into DNA (as a measure of growth) and slowed cell cycle progression without causing cell death. These same authors had previously reported that lycopene inhibited mammary, endometrial, and lung cancer cell growth in a dose-dependent manner.

Lycopene is a relative newcomer on the supplement scene, and its mechanism(s) of action has not been completely elaborated. It is well established that lycopene is an antioxidant (a beneficial compound that scavenges and inactivates potentially dangerous free radicals), but it is not clear that this particular function is what makes it such a potent anticancer compound. Lycopene performs a number of other functions by which it may reduce the risk of prostate cancer. For example, it may:

• Regulate cancer-cell growth by modulating the cell cycle. Lycopene interferes with the progression of the cell cycle in some cancerous cells and thus prevents them from proliferating. In fact, lycopene is a much more effective growth inhibitor of select cancer-cell types than either alpha-carotene or beta-carotene.³⁶
• Increase the level of the tumor-suppressor protein Cx43. Certain proteins, called tumor suppressors, can prevent cells from becoming cancerous. A protein called Cx43 is believed to be one such tumor suppressor. It helps cells communicate with their neighbors, a feature that is linked to minimizing the proliferation of precancerous cells. In cell-culture studies, carotenoids such as lycopene increase the level of Cx43 and may thus prevent cells from becoming cancerous.³⁶
• Regulate the oxidation status of cancer cells. Some transcription factors (molecules that lead to the expression of specific genes and that may cause cells to turn cancerous) are sensitive to the oxidation status of cells.
• Decrease the extent of oxidative damage. Some researchers have noted that in patients with prostate cancer, protein oxidation is higher than normal while lycopene levels are significantly lower than normal. This suggests that higher lycopene levels may prevent protein oxidation, thus reducing the risk of cancer-inducing events in the cells.³⁷
• Increase the activity of carcinogen-metabolizing enzymes. Some carotenoids, such as lycopene, increase the liver’s ability to produce enzymes that inactivate cancer-causing compounds.

DIM May Help Prevent Prostate Cancer

Certain compounds derived from cruciferous vegetables, such as broccoli, cabbage, and cauliflower, are known to be strongly anticarcinogenic. The best known compound is indole-3-carbinol (I3C), which offers other health benefits as well. Closely related to I3C is diindolylmethane (DIM), which consists of two I3C molecules chemically bonded to each other to form a dimer, or “double molecule.”

In one study, researchers in Israel injected 6-week-old male mice subcutaneously in the flank with mouse prostate cancer cells in order to induce the growth of tumors that could be easily observed and measured.³⁸ After 2 weeks, they began to treat the mice with DIM or a control solution. The results showed a dramatic effect of the DIM treatment: the tumors grew much more slowly in the treated mice than in the control mice, ending up about 60% smaller in weight and volume. DIM appeared to be nontoxic and safe at the doses used.

From laboratory examinations of the tumor cells, the researchers deduced that DIM acted by inhibiting cell proliferation through a decrease in DNA synthesis, accompanied by the induction of apoptosis, also known as programmed cell suicide. They concluded, “The results of our study … suggest that cruciferous vegetables and their indolic compounds, I3C and DIM, may constitute an important anticarcinogenic and therapeutic food derivative against this type of cancer, offering natural compounds with minimal toxic effects in the treatment of prostate cancer.”

These results are in accord with similar evidence for the anticancer properties of I3C and DIM found in other studies. Both of these highly beneficial compounds are available as nutritional supplements, which is a more convenient and reliable way to obtain optimal amounts of them than eating cruciferous vegetables every day.

Omega-3 Fatty Acids Reduce Cancer Risk

A number of epidemiologic studies (scientific studies that examine large populations for correlations between disease and some measurable factor, such as diet) suggest that people who consume foods that are rich in omega-3 fatty acids (eg, fish oil), such as the Inuit people who inhabit the Arctic regions, have reduced incidences of certain types of cancer. These compounds (and the fats that are made from them in the body) appear to be particularly protective against breast and colon cancer.

Researchers at the University of Nevada recently published a paper in Cancer Letters demonstrating that omega-3 fatty acids reduce the growth of human colon carcinoma cells.³⁹ They transplanted human tumor cells into mice whose immune systems had been compromised to make them particularly susceptible to cancer. The mice were then divided into different groups: two groups were fed a diet supplemented with omega-3 fatty acids, while the other groups were fed either a low-fat (8% corn oil) or high-fat (24% corn oil) diet that lacked omega-3 fatty acids (corn oil is rich in omega-6 fatty acids).

Mice in the two groups receiving the omega-3 fatty acid-supplemented diet had significantly smaller tumors – up to 90% smaller – than the mice on the omega-6-rich/omega-3-deficient diets. The authors concluded that dietary omega-3 fatty acids possess “significant tumor-suppressing properties” and that the primary tumor-suppressing fatty acid is docosahexaenoic acid [DHA].”

Another important finding was that the low-fat diet (8% corn oil) significantly reduced the growth of tumor cells compared to the high-fat diet (24% corn oil). Together, these results suggest that a good way to inhibit tumor cell growth is to decrease total fat intake while increasing the consumption of omega-3 fatty acids.

Exactly how omega-3 fatty acids suppress tumor growth is still a subject for intense study, but a number of mechanisms have piqued scientists’ interest:

• Promoting apoptosis. Omega-3s help regulate the expression (the “on-or-off” status) of certain genes in cancer cells. As a result, they may tell cancer cells to die – a process called programmed cell death, or apoptosis.
• Inhibiting cell division. Another possibility is that they may instruct cancer cells to stop dividing by inhibiting mitosis – the process by which one cell becomes two cells with all the same genetic material. This is almost as good as telling them to die. Alternatively, omega-3 fatty acids may encourage cancer cells to differentiate into a cell type that is no longer capable of replicating itself without limit and that is thus no longer cancerous.
• Inhibiting angiogenesis. Cancer cells need a steady supply of nutrients to survive and proliferate. Omega-3 fatty acids, which are important nutrients in their own right, may limit the access of other nutrients to cancer cells by inhibiting angiogenesis, the growth of blood vessels to tumors.
• Interrupting hormone production and release. Omega-3 fatty acids may also stall cancer-cell growth in certain cell types by interrupting the normal biochemical processes that govern the production and release of essential hormones.

Not only might they slow cancer growth, but omega-3 fatty acids might also provide a useful adjunct for conventional chemotherapy. For example, animal experiments have shown that concomitant administration of omega-3 fatty acids increases the efficacy of chemotherapy while reducing its side effects. You can think of all these effects of omega-3 fatty acids as a “multiple whammy” against cancer.

Conjugated Linoleic Acid Combats Cancer

Linoleic acid is one of the essential fatty acids, meaning that our bodies require it but can’t synthesize it, so we must obtain it from food sources. We can’t be healthy without a certain amount of linoleic acid in our diet, because we need it for the formation of cell membranes and as a precursor to other compounds, such as prostaglandins.

A tiny change in the molecular structure of linoleic acid results in a compound called conjugated linoleic acid (CLA), which is actually a mixture of closely related molecules all having exactly the same chemical formula as linoleic acid but with different molecular structures due to different arrangements of the atoms in the molecules. These sibling compounds are called isomers, and collectively they constitute CLA.

In our bodies, some of the CLA we ingest winds up being incorporated into molecules called phospholipids, which are the principal structural components of cell membranes. Although CLA may not be essential in the same sense that linoleic acid is, it is nonetheless important because of its varied health benefits. Here are some of the principal ones:

Research on CLA has shown it to be a potent anticancer agent, and scientists are excited by the fact that its therapeutic actions occur at much lower concentrations than most other naturally occurring anticarcinogenic compounds. CLA is the only fatty acid that has been shown unequivocally to inhibit cancer in animals. In mice, for example, it has been found to inhibit the development of cancer of the skin, stomach, liver, lungs, and mammary glands.⁴⁰

There have been very few human clinical trials on the effects of CLA, but experiments on human cancer cells in vitro (in test tubes) have confirmed CLA’s anticancer properties, especially against malignant melanoma and colorectal, prostate, breast, and lung cancers.⁴¹ It was once believed that CLA’s anticancer and other therapeutic properties were due largely to an antioxidant effect. More recent research, however, has failed to demonstrate any such effect. There are many theories and speculations about how CLA works, but no clear answers.

Vitamin E – A Powerful Agent Against Prostate Cancer

Vitamin E, which exists in eight chemically similar forms (four tocopherols and four tocotrienols), is a potent antioxidant that has long been known in the alternative medicine world as an integral part of cancer prevention. Only recently, however, has mainstream medicine begun to embrace the idea, albeit slowly, that vitamin E supplementation may play a pivotal role in preventing prostate cancer.

One of the first large-scale studies (more than 29,000 men) to show the significant impact that vitamin E can have on the development of prostate cancer was the Finnish a-Tocopherol, ß-Carotene Cancer Prevention Study, called the ATBC study for short.⁴² a-tocopherol is the most potent form of vitamin E, and ß-carotene is a precursor of vitamin A. The researchers found that daily supplementation with 50 mg of a-tocopherol – not a very high dose – decreased the incidence of prostate cancer by 32% and reduced mortality from prostate cancer by 41%.

Because of the ATBC study’s unexpected but impressive results, further research has been done to evaluate how a-tocopherol might work against prostate cancer. In 2000, scientists at the University of Utah examined the effects of this vitamin on human prostate cancer cells.⁴³ They showed that adding it to these cells in the laboratory caused them to fragment and die.

While a-tocopherol has been the most widely studied form of vitamin E, other forms are also showing promise in the fight against prostate cancer. A report published recently in the American Journal of Clinical Nutrition examined the importance of gamma (?)-tocopherol in our diet.⁴⁴ The authors concluded, “Results from recent epidemiologic studies suggest a potential protective effect of ?-tocopherol against cardiovascular disease and prostate cancer … . We propose that, although a-tocopherol is certainly a very important, if not the most important, component of vitamin E, ?-tocopherol may contribute significantly to human health in ways that have not yet been recognized.”

Another recent study, from The Johns Hopkins University School of Hygiene and Public Health, examined the association between different forms of vitamin E, including a-tocopherol and the closely related ?-tocopherol, and the development of prostate cancer.⁴⁵ The study also included the mineral selenium, a potent antioxidant in its own right. A total of 10,456 men were followed over an 8-year period, during which 145 of them developed prostate cancer. Of these 145 men, 117 were then compared to 233 very similar men in the study who had not developed the disease. Blood levels of both a- and ?-tocopherols were found to be lower in men who developed prostate cancer then in men who did not. Interestingly, the strongest association was found with ?-tocopherol.

About 200,000 men will be diagnosed with prostate cancer this year. Many thousands of them will have prostate surgery or take medications that could leave them incontinent, impotent, and depressed. However, by not smoking, eating less of the wrong kinds of fat, and taking supplements that contain both a- and ?-tocopherols, along with selenomethionine and lycopene, men can optimize their chances of leading a long and happy life, free of the spectre of prostate cancer, and with their private parts functioning as nature intended.

Mastic Kills Colon Cancer Cells

Mastic is a gummy resin that exudes from mastic trees (Pistacia lentiscus). Since ancient times, mastic has been used in Mediterranean cultures as an antiseptic, a food antioxidant, a chewing gum and breath sweetener, a flavoring additive in a variety of traditional foods and drinks, and a remedy for stomachache, indigestion, and ulcers.⁴⁶ The medicinal value of mastic lies mainly in its lethal action against a number of species of harmful bacteria, most notably Helicobacter pylori.^47-49 This nasty little bug, which infects roughly half the people on earth, is the primary causative agent for nonerosive gastritis (a chronic inflammation of the stomach) and most gastric and duodenal ulcers, collectively known as peptic ulcers.

Although H. pylori is not believed to cause stomach cancer, it is strongly associated with this terrible disease: infected individuals are three to six times more likely to get stomach cancer than those who are free of infection.⁵⁰ Thus, eradicating H. pylori from the GI tract may indirectly help prevent stomach cancer.

A recent study of cancerous human colon cells by scientists in Florida and Greece found that mastic killed the cells in a dose-dependent and time-dependent manner.⁵¹ The higher the mastic concentration and the longer the incubation period, the greater the killing effect.

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