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Beyond Colonoscopy to Real Protection

September 2009

By Julius Goepp, MD

Foods That Fuel Colon Health

Not surprisingly, a wide range of nutrients beyond polyphenols have outstanding cancer-preventive track records. Here are brief summaries of a few of them. Their active ingredients (as high-potency standardized extract) are readily available in supplement form.


Both epidemiological and animal studies have conclusively illustrated the cancer-preventive effects of many of the compounds found in garlic.47-49 Aged garlic extract in particular acts not only as a potent antioxidant, but also:

  • prevents cancer-causing DNA changes
  • induces apoptosis (cell destruction)
  • increases activity of toxin-neutralizing enzymes
  • decreases activity of toxin-activating enzymes.50-52

Aged garlic extract also boosts immunity against cancer cells.53,54 These combined activities prevent the formation of pre-cancerous aberrant crypt foci (ACF).55

A Japanese research group recently provided dramatic new data on aged garlic extract’s power to prevent colorectal cancer in humans in a study of 37 patients diagnosed with colorectal adenomas—the precursors to cancer.56 Active group patients took aged garlic extract 2.4 mL per day (equivalent to about 720 mg powered extract57); control patients received a miniscule 0.16 mL per day; all patients had endoscopy done at the beginning of the study, and at 6 and 12 months.56 Control patients displayed the expected steady increase in number and size of adenomas—but in the supplemented group both adenoma number and size had been significantly reduced by the end of the 12-month period. The researchers concluded, “Aged garlic extract has multiple pathways to reduce cancer incidence and suppress its growth and proliferation.”

As much as 7,200 mg/day of aged garlic powder has been consumed for up to six months without noted side effects.58


Like garlic, ginger has been a mainstay of traditional medicine for more than 2,500 years. And, like garlic, ginger is now coming into its own in the eyes of Western medical scientists. Ginger’s multiple chemopreventive benefits have been reported in a wide range of experimental models.59 Key compounds in ginger and its extracts limit the oxidative damage to cells caused by free radicals. They also lower levels of signaling molecules called cytokines, specifically those that provoke an inflammatory response. This dual mode of action results in increased cancer-destroying cell destruction.60,61 Some ginger components also increase the activity of vital enzymes that detoxify carcinogens present in the body.62,63

Indian researchers provided direct evidence of ginger’s chemopreventive power in rats with chemically induced colon cancers in two recent studies.64,65 After injection with a potent carcinogen, animals were either supplemented with ginger or given normal diets. In both studies the incidence of cancers and the number of individual tumors was significantly reduced in the supplemented groups. The first study also detected lower levels of oxidative agents and higher levels of natural antioxidants in supplemented animals, while the second study further showed a decrease in the activity of bacterial enzymes that release intestinal toxins and damage the colon’s natural protective mucous layer.

Cruciferous Vegetables and Sprouts

People who eat a diet rich in so-called cruciferous vegetables (the cabbage/broccoli/Brussels sprout family) are known to have lower rates of colon and other cancers.66,67 These vegetables and their sprouts contain key compounds and breakdown byproducts—including sulforaphane and indole-3-carbinol (I3C)—that exert potent antioxidant and anti-inflammatory effects in the body. They also specifically target and neutralize enzymes that would normally activate dietary carcinogens. In other words, they simultaneously keep cancer from developing and destroy emerging tumors in the early stages of the disease through cancer cell death.68-73

A number of animal studies demonstrate that supplementation with cruciferous vegetable extracts blocks cancerous changes in rat colons after the animals have already been exposed to dangerous, powerful carcinogens.67,73,74

Research on humans is just as promising. Several years ago, a group of researchers in Britain conducted a breakthrough study with enormous implications for human colon cancer chemo-prevention using cruciferous vegetables. They tested 20 healthy volunteers for carcinogens that can result from a diet high in red meat. The testing took place at the end of three distinct 12-day phases.

In the first phase, the study subjects ate no cruciferous vegetables at all. In the second phase, they ate 250 grams of broccoli and Brussels sprouts a day. In the third and final phase, they once again ate no cruciferous vegetables, in order to “wash out” any potential anticarcinogenic effect.75

Testing revealed that at the end of the second phase—during which they’d eaten broccoli and Brussels sprouts every day—the subjects’ levels of detoxifying enzymes had risen dramatically, while urine tests showed a proportionate boost in detoxified carcinogenic molecules. In other words, broccoli and Brussels sprouts effectively neutralized dietary carcinogens in the body, rendering them harmless.

A remarkable 2008 study from England revealed that the cruciferous vegetable compound I3C intensifies the effect of the colon cancer chemotherapy drug oxaliplatin.76 Adding I3C helped researchers to kill off cancer cells at a six-fold higher rate compared to the chemotherapy drug alone.

This is more encouraging news. Like resveratrol, I3C may one day help physicians limit doses of toxic chemotherapy drugs like oxaliplatin and 5-fluorouracil—and offset the painful, debilitating side effects they inflict on cancer patients.

Eight Common Cancer-Fighting Nutrients

Vitamins and trace minerals act as powerful antioxidants, making them useful candidates for colon cancer chemoprevention. Numerous large-scale epidemiological studies point to the vitamins E and D, plus calcium, as potent colon cancer fighters.77-79 The data on vitamin D, for example, is excellent. Vitamin D reduces cancer cell proliferation in the colon—a necessary first step in cancer development.80

Interestingly, a recent study showed that vitamin E can make colon cancer cells more vulnerable to the lethal action of exisulind—a compound known to initiate programmed cancer cell death.81 Folate and vitamins B6 and B12 are also by expert consensus excellent chemoprevention candidates, owing to the critical role each plays in protecting healthy DNA.82

Selenium is an essential trace mineral with remarkable antioxidant properties. It’s also one of nature’s primary cancer-preventive nutrients.

Selenium activates a number of key enzymes in the body that keep cancer from developing.83 Preliminary studies have shown that people with higher selenium levels are at decreased risk of cancer.84 A study from the National Institutes of Health showed that high selenium reduced the risk of advanced colorectal adenomas, a cancer precursor, by nearly 25%! It afforded even greater protection in high-risk groups, including smokers.85

Conversely, people with colon cancer have significantly lower blood selenium levels.86 Fortunately selenium supplementation not only boosts serum selenium levels, but also ramps up the activity of vital cellular antioxidant systems that help prevent cancer from forming.87 There’s also compelling evidence that selenium maximizes the anticancer effect of sulforaphane, the compound found in cruciferous vegetables, making the two a potent combination for bowel health.83

A growing body of epidemiological, clinical, and experimental evidence suggests that the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—abundant in cold-water fish and fish oil—may also reduce the risk of colorectal cancer.88

Important findings from the Physicians’ Health Study suggest that consuming fish and fish oils may protect against colorectal cancer. In this long-term prospective study of male physicians, greater intake of fish and omega-3 fatty acids was associated with a reduced risk of colon and rectal cancers.89

Experimental studies suggest that these omega-3 fatty acids may exert numerous anti-cancer effects, including regulating cell proliferation and apoptosis as well as fighting angiogenesis and metastasis. Additionally, some scientists have suggested that omega-3 acids may sensitize colon tumors to drugs that suppress the growth of abnormal tissue.90 Together, these findings point to an important role of omega-3 fatty acids from fish oil in averting colon cancer.


Colon cancer remains a serious threat to millions of men and women each year, and standard medical and surgical therapies to treat the disease are far from adequate. Because cancers develop in the colon as a direct result of its constant exposure to toxic chemicals and byproducts of digestion, a natural, nutrient-based approach to prevention makes good sense. Medical science is just beginning to gain a full appreciation of how nutrients can help avert this deadly disease. As renowned Italian surgeon and nutrition expert Dr. Duilio Divisi has written: “It has been estimated that 30-40% of all kinds of cancer can be prevented with a healthy lifestyle and dietary measures.”91 Dr. Divisi remarked that in addition to the role of polyphenols described above, “Protective elements in a cancer-preventive diet include selenium, folic acid, vitamin B12, vitamin D, chlorophyll [abundant in leafy vegetables] and antioxidants… A diet drawn up according to the proposed guidelines could decrease the incidence of breast, colon-rectal, prostate and bronchogenic cancer.”91

If you have any questions on the scientific content of this article, please call a Life Extension Health Advisor at 1-800-226-2370.


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