Doctor’s Tip: How to really prevent colon cancer |

Doctor’s Tip: How to really prevent colon cancer

Dr. Greg Feinsinger

Dr. Greg Feinsinger
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March was colon cancer awareness month, and several Valley View Hospital ads about screening appeared in the P.I. As I noted in a health tip column a few months ago, regular screening involving a colonoscopy starting at age 50 (earlier in people at high risk such as family history of colon cancer or polyps) can clearly save lives. However, what’s been missing, I feel, is the message that colon cancer is due to what we eat or don’t eat, and is therefore preventable in most cases.

Colon cancer is the second leading cause of cancer death in the U.S., claiming the lives of some 50,000 people every year. The average American has about a 1-in-20 chance of developing it, indicating that due to screening many cases are caught at an early stage and treated successfully. The first stage in the development of colon cancer are “aberrant crypt foci” — abnormal clusters of cells in the lining of the colon. These slowly develop into polyps, over years become cancerous and eventually metastasize.

It has long been known that in people in Africa and other parts of the world where the traditional diet was plant-based, colon cancer was extremely rare. For a long time, it was thought that the reason was the high fiber intake associated with plant-based diets. Now, however, it is thought that this phenomenon is due to particular nutrients present in plant-based diets, and harmful components in the animal-based Western diet.

1In India, colon cancer rates are very low. Most of the people are Hindus and for religious reasons are vegetarians if not vegans. So they eat lots of green leafy vegetables, lentils, beans, fruit and unprocessed grains. But Indians also eat a lot of the spice, turmeric, which is active against cancer cells in vitro (in a lab).

Dr. Michael Greger (, “How Not to Die” book) points out that in your body, turmeric comes in direct contact with the lining of the colon, and it has been shown to reverse the first stage of colon cancer, the aberrant crypt foci. Turmeric along with another plant nutrient called quercetin (found in red onions and grapes) given for six months decreased the number and size of colon polyps. And even in patients with advanced colon cancer, who had failed chemo and radiation, turmeric extract stalled the disease in five out of 15 patients, and without the side effects of chemo.

2Phytates occur in the seeds of plants, including whole grains, beans and nuts. According to Dr. Greger, they target cancer cells through antioxidant, anti-inflammatory and immune-enhancing activities. They boost the activity of the first line of defense, white blood cells. They are among the many nutrients in plants that help block the formation of new blood vessels that feed tumors. And in the lab they cause cancer cells to revert back to normal.

3Berries have been shown in vitro to suppress colon cancer cells. And after nine months of daily black raspberries via enema (don’t try this at home), the polyp burden of 14 patients with familial polyps was cut in half.

4Both processed and unprocessed meat intake is associated with an increased rate of several cancers, including colon. This is thought to be due at least in part to the type of iron found in meat, called heme iron, which is particularly associated with colon cancer. If you eat nonheme iron, found in plant food, your intestines boost absorption if you need more and decrease absorption if you have too much. But this mechanism doesn’t work with animal heme iron. This is a problem, because excess iron in the body leads to a particularly harmful type of free radical, called hydroxyl, and free radicals can lead to cancer.

Don’t think you can get out of your colonoscopy by suddenly becoming plant-based (the procedure is really not that bad anyway). If you have been plant-based since early childhood, your risk of colon cancer is extremely low unless you have a positive family history, and even then it’s much lower than if you had been on an animal-based diet. If you become plant-based later in life, you will certainly decrease your risk of many cancers including colon, but remember colon cancer develops over several years so you still need screening in case you have a pre-existing early stage of colon cancer.

Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at

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