※上記の広告は60日以上更新のないWIKIに表示されています。更新することで広告が下部へ移動します。

アルカディア翻訳会 2008年4月課題  

日時:4月20日(日)14:00—17:00

会場:渋谷区立大向区民会館 和室2号
4月はフォーブスの記事を扱います。①から③までできる範囲内で訳してください。
The Cancer Diet?
 
 
Lots of foods and minerals stop tumors in rats. Proving the effect in humans is another matter.
①Ohio State University cancer researcher Gary Stoner may have found a breakthrough cancer preventive: freeze-dried black raspberries. Over the last decade he has fed large amounts of the berries to rats and injected them with potent carcinogens. Rats that eat the berries develop up to 80% fewer colon tumors than those who don't.
Small human trials to see if berries slow precancerous lesions are under way. If these succeed, much larger trials would be needed to confirm an effect. It could take five years--or more.
So it goes in the murky world of studying cancer and diet. Each year brings a drumbeat of lab studies suggesting links between various dietary chemicals and cancer prevention: broccoli, soy, ketchup, bran, selenium. And then the studies come a cropper. "Green tea is the cure-all one week, and the next the data isn't good," says nutritionist Linda Chio, who works at the New York University Clinical Cancer Center. "People say, 'Tell me all I have to do is eat this and stop this and I will be able to avoid cancer.' We are not there yet." She tells people to eat lots of fruits and vegetables, go light on red meat, stay slim and not sweat the details.
②Cancer takes years or decades to develop, so reliable trials are tough to perform. Gastroenterologist Moshe Shike, who heads nutrition for the Memorial Sloan-Kettering Cancer Center, says what people don't want to hear: "We don't know of any nutritional regimen we can positively say prevents cancer." Adds Harvard School of Public Health epidemiologist Walter Willett: "It is hard to put a finger on a specific food that prevents cancer in general."
③One reason to think diet has an impact on cancer is that countries with differing diets have very different cancer rates. The Japanese have lower rates of prostate and breast cancer than the U.S., a fact attributed to their greater intake of soy and low-fat foods. And rates of stomach cancer are much higher in many Asian countries, where the food is heavily salted. By some estimates, 30% of cancer risk is attributable to diet.
But Willett says it's becoming clear that most of the dietary risk is due not to specific foods but to Americans' obesity and bulging waistlines, which, he says, are second only to smoking as preventable causes of cancer. One 900,000-person study in 2003 found that obesity raised the cancer risk by 52% in men and 62% in women. Alcohol is also a clear risk factor for many cancers. After these, specific foods make up a fairly modest 6% to 7% of cancer risk, Willett estimates. H. Gilbert Welch, a researcher with the Department of Veterans Affairs, calls the huge effort to find a dietary solution "tinkering" and argues that it would be better to invest in new treatments.』
Here is a rundown of the most debated cancer causers and preventers among foods and supplements:
Fruits and vegetables
Fruits and vegetables are thought to be beneficial, but the evidence "is much weaker than it was ten years ago," says Harvard's Willett. Two giant studies reported in the Journal of the American Medical Association, for example, found no relation between breast cancer risk and fruit and vegetable intake. Hope springs eternal: A recent panel convened by the not-for-profit American Institute for Cancer Research concluded fruit and vegetable intake probably reduces the risk of stomach, esophagus and mouth tumors.
Red meat
Many epidemiological studies show that a high intake of red meat bolsters colon cancer risk. The reasons are unclear but could include carcinogens produced during grilling. A 2005 American Cancer Society study of 149,000 adults found that those who ate the most red meat had a 40% higher risk of colon cancer. The AICR panel calls the red meat/colon cancer link "convincing."
Vitamins A, C, E and beta-carotene
Millions take these vitamins and antioxidant supplements in the hope of preventing cancer and other ills. Some antioxidant studies showed decreased cancer risk, including one trial in China. But several big studies have found no effect. A study of 20,000 British heart patients compared vitamins with placebo pills for five years and found no difference in cancer rates or heart risk, even though blood levels of the vitamins skyrocketed. A 2004 Danish analysis of 14 previous trials found antioxidant vitamins and beta-carotene were duds in preventing gastrointestinal tumors.
This year the Danes published a bigger analysis in JAMA that showed a 5% higher risk of death among those who took significant amounts of vitamin A, E or beta-carotene. (Vitamin C was neutral.) Senior author Christian Gluud of Copenhagen University Hospital advises against using supplements.
The industry group Council for Responsible Nutrition says the cancer studies were done on sick people and don't shed light on antioxidant effects in healthy people. It (and some doctors) argues the JAMA study is skewed because it excluded positive results.
Soy
Japanese men are less likely to get prostate cancer than Americans. Is their higher soy intake responsible? Soy contains estrogenlike compounds that inhibit the hormones that fuel tumor growth. One recent study surveyed the diets of 43,509 Japanese men and found that those who ate a lot of soy had half the risk of localized prostate cancer. But they didn't have lower rates of advanced prostate cancer. A toss-up.
Selenium
Interest in this element (found in nuts, meat and fish) exploded in 1996 after University of Arizona researchers studying selenium supplements to prevent skin cancer unexpectedly found they reduced the incidence of prostate cancer by 60% in a 1,312-patient trial. But those results aren't definitive, and the study found higher rates of certain skin cancers and diabetes in the folks who got the selenium. A U.S.-government-sponsored study comparing selenium and/or vitamin E with placebo pills in 35,000 healthy men should settle the matter. Results may not come for five years. Excessive selenium is toxic.
Tomatoes
In 1995 Harvard researchers studying 48,000 male health workers found that the more tomato products they ate, the less likely they were to be diagnosed with prostate cancer over the next six years. They attributed this to the antioxidant chemical lycopene in the fruit. But the Food & Drug Administration recently analyzed all the data on cancer, lycopene and tomatoes in response to companies seeking to make health claims. Its conclusion: There is "no credible evidence" that lycopene prevents any tumor and only "very limited evidence" that tomatoes stave off prostate cancer.
Low-fat diet
Researchers have long wondered whether the high breast cancer rate in the U.S. is due to a high-fat diet. But big human trials have shown little relationship. In 2006 a government study of 49,000 postmenopausal women found that those assigned a low-fat diet eased their risk of breast cancer by 9% over eight years; the difference was not statistically meaningful. (It did help with ovarian cancer.) Meanwhile, two trials have examined whether a lower-fat diet prevents breast cancer from recurring. One found a modest effect, the other none.
Fiber
Another theory is that fiber in food may block colon cancer by removing carcinogens from the bowel. In 2003 a survey that tracked 520,000 Europeans (not a controlled trial) found that those who ate the most fiber had a 40% lower risk of colon cancer. But that was followed in 2005 by a 725,000-person
Harvard survey finding that fibrous diets had little impact on colon cancer rates. Meanwhile, several controlled trials examined whether high-fiber diets or bran supplements could prevent precancerous colon polyps in high-risk patients. They didn't help.