| Prevention of Colon Polyps/Cancer
The colon is the large intestine. It begins where the small
intestine ends, near the appendix inside the right lower abdomen.
The colon extends in a wide loop, up the right side of the abdomen
to the liver, and across to the left side of the abdomen where it
turns down connecting finally to the rectum.
Polyps and Cancer
Polyps are growths that form on the inside lining
of the colon. They are usually shaped like mushrooms or dome-like
buttons, and vary in size from a tiny pea to larger than a plum.While colon polyps start out as benign tumors, certain types of
polyps (called an adenoma, or adenomatous polyp) may turn into
cancer. The risk is greater as the polyp gets larger. Adenomatous
polyps can be removed before they become cancerous with a procedure
called colonoscopy. Under light sedation, a lighted flexible tube is
inserted into the colon, allowing the physician to see the inside
of. the colon and remove polyps.
Causes and Risks
The complete cause of polyp formation and colon cancer is
unknown, but it is known that heredity plays a key role. Certain
genes seem to prevent colon cancer from developing. Some people may
lose these protective genes. A person whose parents, brothers or
sisters have colon cancer or polyps is at significantly greater risk
of developing it. There is also risk, but to a lesser degree, if
uncles, aunts or grandparents have had the disease. Therefore,
people with a family history of polyps and colon cancer should be
evaluated by their physician and examined regularly.
Prevention - Diet
It only makes sense that a disease that originates
in the gut should somehow be related to diet. While genetic factors
are probably the most important, let's look at the effects of diet.
Vegetables and fruits
The red, yellow, orange and green colored fruits
and vegetables such as peppers, oranges, strawberries, and carrots
are particularly rich in a complex mixture of substances called
antioxidants. The cruciferous vegetables (cabbage, Brussels sprouts,
broccoli) have very high levels of natural cancer fighting
chemicals. Brussels sprouts and broccoli are exceedingly high in
these. There is increasing medical data that people who eat these
foods plus generous amounts of unprocessed grains have less colon
cancer. There is no medical evidence that taking antioxidant
supplements such as vitamin C and E and betacarotene is helpful.
Folic Acid
Data was published in 1999 which studied a large
group of nurses over a 14 year period. Folic acid or folate seemed
to be very protective for these females 'especially those who
received over 400 micrograms a day from food and/or a multivitamin.
It may also be of benefit in colon cancer prevention.
Meats and saturated fats
Meat contains saturated fat as do many prepared
products such as ice cream and especially non-animal foods such as
pastries, sauces, etc. Always read the food labels to see how much J
saturated fat a food contains. These fats are broken down by the
body's digestive juices and bile. Some of these byproducts are known
to cause cancer in laboratory animals. There is some evidence that
meat rich diets may increase the risk of breast cancer but this has
not been shown in colon cancer. Nevertheless, a reduced meat and
saturated fat diet probably contributes to colon health to some extent.
Fiber
Studies in the 1960's and 1970's seemed to relate
a fiber rich diet with reduced Colon cancer in rural Africans.
However, the hope that it could reduce colon cancer risk has been called
into question by a large study of nurses who had little or no change
in developing colon cancer or polyps even when eating up to 5 grams
of fiber a day. This is just one study and the positive health
benefits of high fiber foods are many, so these foods are still
highly recommended.
Calcium
Calcium is one of the most common minerals in the
body. It is necessary for bone strength and for many of the body's
important chemical processes. For example, it is needed in regulating
the growth of cells. Animal studies have found that a lack of
calcium leads to excessive cell growth in the colon. It is not clear
if calcium has a cancer preventive benefit for humans. Still,
since it is important to the body in so many other ways, everyone
should get enough calcium in the diet. All adults should have 1000
mg per day. After menopause, females have a greater risk of
osteoporosis (loss of calcium causing bones to weaken), and they
should have 1500 mg of calcium a day.
A quart of milk a day provides adequate calcium.
Most people do not drink a quart of milk everyday, but there are
other sources of calcium. Dairy products (such as cheeses and
yogurt), shellfish, seafood and many leafy green vegetables contain
calcium. The calcium in leafy vegetables is not as available for use
by the body as calcium in milk. Some people on low calorie or
special diets may not be able to get enough calcium in their diets.
In these cases, the physician can recommend a calcium supplement.
Calcium carbonate is the best and least expensive.
Aspirin
Some, but not all, medical studies show that the
incidence of cancer of the colon may be less in those people who
take aspirin regularly. It is known that prostaglandin (a
hormone-like substance produced by the body) may promote excessive
or abnormal cell growth in the intestine. Aspirin appears to interfere with
prostaglandin, which may account for a possible role in preventing
colon cancer.
Aspirin can cause stomach ulcers, serious bleeding
or hemorrhagic strokes, so it should only be taken with the approval
of a physician.
Other Factors
The large nurse's study, mentioned before, has
shown other factors that appear to be related to colon cancer.
- Cigarette Smoking-Long-term smokers had more colon
cancer than non-smokers
- Leisure Time Activities-Those nurses who were more
active in their daily lives had fewer cancers
- Estrogen-Those nurses who continued to use
estrogen hormones had fewer cancers. However, it is not recommended
that you take estrogen just for this possible reason
Summary
- Genes-if there is colon cancer or polyps in
your family, have a colonoscopy to detect early cancer or removal of
polyps
- Surveillance-yearly stool exam for hidden blood
and sigmoidoscopy (short exam) every 5 years or colonoscopy every 10
years or so, starting at age 50
- Remove polyps when found, a polyp that is
removed cannot become cancer
- Diet-eat a diet high in yellow, red and orange
fruits and vegetables, low in meats and saturated fats and high in
fiber
- Calcium-1,000 to 1,500 mg a day from diet or supplements
- Folic Acid-take a daily supplement or
multivitamin with at least 400 mcg of folic acid
- Aspirin-may be helpful but should be discussed
with physician
- Keep an active lifestyle - walk, exercise 9. Do
not smoke cigarettes 10. Estrogen hormones
See the separate brochure, Colon Polyps and Cancer, for a full
description of these conditions. |