by Elyse M. Rogers
U.S. Japan & Types of Cancer
In the last two columns I discussed cancer-prevention facts with a special emphasis on lung cancer. One of the interesting international facts about cancer is the differences between types of cancer and their incidence around the world.
For instance, as I mentioned, Japan has a very high incidence of stomach cancer and a low incidence of colon cancer, while the U.S. has just the opposite. Japan has the dubious honor of having the world’s highest incidence of stomach cancer.
Colon cancer rates have risen in modern times, as countries become more affluent and switch to a diet high in red meats and fats. You can see the diet influence in the risk factors for colon cancer listed below:
- Being over 40.
- Having ulcerative colitis or other bowel disease.
- Eating a high fat (particularly red meat) diet.
- Eating a low fiber diet.
- Having a family history of colon cancer.
Diet is important in colon cancer for some interesting physiological reasons. Studies have shown that the time it takes for food to pass through large intestine or colon varies considerably with the type of food eaten. Ponder these findings:
- In a vegetarian/high fiber diet, the colon-passage time is 30 hours.
- In a high meat/low fiber diet, the colon-passage time is about 70 hours.
When passage-time in the large intestine is increased, more toxins are produced and there is more time for the body to absorb those toxins. Also, in heavy meat eaters, the body secrets more bile acids which can be carcinogens (cancer-producing substances). A test for bile acids showed that the U.S. citizen has a bile-acid level of 260, while a Seventh Day Adventist and a Japanese citizen have bile-acid levels of only 50.
A high fat/low fiber diet is implicated not only in colon cancer, but in a growing number of other types of cancer. One of the suprising cancers that seems related to the high fat diet is breast cancer in women. Unfortunately, with the increasing inclusion of red meat in the Japanese diet, breast cancer rates are rising in Japan which traditionally has had a very low rate of breast cancer.
Stomach cancer—the most prevalent type of cancer in Japan—is also diet related. If you are familiar with the Japanese diet, you might already have guessed that it is the high level of salt and dried fish in the diet that are suspected of promoting stomach cancer. The recommended level of daily salt intake was set by the World Health Organization at five grams per day.
In America the intake is about 8-10 grams a day, but in Japan it is from 12 to 20 grams per day! Dried and pickled fishes are especially popular in Japan, but in addition to salt they often contain high amounts of carcinogen factors. The popular katsuo-bushi (dried bonita) and iwashi (sardines) are particularly high in carcinogen materials. (Carcinogens do not necessarily cause cancer, but are suspected of possibly promoting conditions that encourage cancer.)
It is interesting to note that in addition to the highest stomach cancer rate in the world, Japan also leads the world in strokes. Strokes are often caused by hypertension or high blood pressure and this condition is more prevalent in societies that include high amounts of salt in the diet.
To prevent both stomach and colon cancer, good dietary habits are a must. Some suggestions:
- Reduce calories in the diet (keep thin).
- Reduce fat intake by at least 20%.
- Increase the intake of fresh fruits and vegetables. Try including one or two raw vegetables as well.
- Get plenty of fiber. (Found in whole wheat products, unpolished rice, fresh vegetables, etc.)
- Make sure the amount of vitamin A and C in the diet is adequate. (Citrus fruits and juices are high in vitamin C, and green leafy vegetables are rich in vitamin A.)
In addition to dietary measures, for all types of cancer prevention, doctors suggest that you refrain from smoking, get regular exercise and be moderate with the use of alcohol.
The cost of cancer to Americans is an estimated ¥800 million per year, so there’s a financial as well as health reason for preventing cancer. Prevention, of course, is the ideal, but it not always possible; however, early detection can often mean a complete cure. Since pain is usually a late symptom of cancer, chronic indigestion, difficulty in swallowing or a change in bowel habits should signal immediate medical evaluation.
Some scientists claim that 80% of all cancers are preventable. Let’s do our part to eat sensibly, exercise regularly and watch our vices. Who knows? Someday scientists might find that “foreigners in Japan” are the people on the globe most cancer-free. Honto ni!