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New Scientific Consensus Statement Issued on Preventing Colon Cancer; Focuses on Wheat Bran Fiber and Regular Screenings of People Aged 50 and Over

NEW YORK, April 23 — To enlist the public in the fight against the second leading cause of cancer deaths in this country, the American Health Foundation today issued the first global scientific consensus statement on the prevention of colon cancer, a disease that claims the lives of nearly 55,000 men and women annually.

The new consensus statement was authored by 11 global diet and cancer experts. After evaluating more than 100 scientific studies conducted during the past 25 years, these experts agreed that colon cancer could be largely prevented if people would add more fiber to their diet and if men and women over age 50 would get regular screenings.

"The recommendations of this new consensus statement should serve as a wake-up call for the public," said Moshe Shike, M.D., director of the Memorial Sloan-Kettering Cancer Prevention and Wellness Program and one of the authors of the consensus statement. "Preventing colon cancer is not an issue requiring additional fact-finding before action should be taken. With what we know now, we can take some very significant steps towards preventing one of the most common and deadly cancers today."

Adds Sidney J. Winawer, M.D., chief of Memorial Sloan-Kettering Cancer Center's Gastroenterology and Nutrition Service, "There has never been a better time to educate the public about the prevention of colon cancer. The long natural history of colorectal cancer provides an opportunity for effective primary and secondary prevention."

Concerning primary prevention, the consensus statement specifically focused on one major recommendation: people of all ages need to get more fiber in their diet, and especially wheat bran fiber. As an insoluble fiber, wheat bran has been shown to increase fecal bulk and weight as well as the frequency of elimination, thus reducing the colon's exposure to a carcinogen. At the same time, consuming wheat bran decreases transit time in the G.I. tract, which also reduces exposure to a carcinogen.

Wheat bran is also unique among fiber sources in its inhibiting effects on colon cancer development, the scientists concluded. "Experimental studies using wheat bran show that of all the fibers tested, wheat bran is the most protective against colon tumor development," said Joanne R. Lupton, Ph.D., professor of nutrition at Texas A&M University. In fact, according to Findlay Macrae, M.D., a gastroenterologist at the Royal Melbourne Hospital in Australia, "data from large human intervention trials indicate an inhibition of the growth of colonic polyps (precursors to cancer) with wheat bran diets, verifying the wheat bran/colon cancer connection."

But there are other reasons why Americans should be getting more wheat bran in their diets. At a time when the National Cancer Institute reports that Americans are only getting about 15 grams of fiber a day — or half of what they need — the scientists point to wheat bran as the way to fill this gap. Because it is a concentrated source of dietary fiber containing almost 40 percent dietary fiber, most wheat bran foods, such as ready-to-eat cereal, provide an average 3 or more grams of fiber per serving. In comparison, reports Joanne L. Slavin, Ph.D., R.D., professor at the University of Minnesota's Department of Food Science and Nutrition, most popular American foods are not high in dietary fiber and even common serving sizes of grains, fruits and vegetables only contain 1 to 3 grams of dietary fiber.

"A lot of foods people believe to be high in fiber just aren't" explained Dr. Slavin. Citing a 1997 review of 228 commonly consumed American foods reported in the Journal of the American Dietetic Association (97:1139), Dr. Slavin noted that only 10 percent contained more than 3 grams of dietary fiber while three-quarters contained 2 grams or less. As a result, said Dr. Slavin, there is a 10 gram gap in dietary fiber intake which most Americans don't know how to address. Accordingly, the consensus statement recommends that in addition to fruits and vegetables, Americans should get 2 servings of foods high in wheat bran fiber a day, especially cereal products that contain 5 or more grams of dietary fiber per serving.

Besides recommending more wheat bran in the diet, the consensus statement promotes regular screenings of men and women aged 50 and over as the secondary prevention strategy. According to one of the statement's authors, John H. Bond, M.D., chief of the Gastroenterology Section at the Minneapolis Veterans Administration Medical Center, "colorectal cancer has a long preclinical phase, safe and accurate diagnostic tests are available, and early detection improves survival."

A recent consensus conference which served as the platform for developing the U.S. consensus statement — "Primary Prevention of Colorectal Cancer and Polyps: The Role of Fiber" — was convened by the American Health Foundation and supported by an educational grant from the Kellogg Company. Chaired by Moshe Shike, M.D., and Sidney Winawer, M.D. of Memorial Sloan-Kettering Cancer Center, the conference was also attended by the following top scientists who served as the authors of the consensus statement: John H. Bond, M.D., VA Medical Center in Minneapolis; Robert J. Cousins, Ph.D., University of Florida; David L. Earnest, M.D., University of Arizona; David Kritchevsky, Ph.D., The Wister Institute; Joanne R. Lupton, Ph.D., Texas A&M University; Findlay Macrae, M.D., Royal Melbourne Hospital, Australia; Bandaru S. Reddy, Ph.D., D.V.M., American Health Foundation; Joanne L. Slavin, Ph.D., R.D., University of Minnesota; and Gary Williams, M.D., American Health Foundation. Colon cancer is second only to lung cancer in terms of cancer deaths in the U.S., claiming the lives of nearly 50,000 men and women annually. According to the National Cancer Institute, 7 percent of Americans will develop the disease within their lifetimes and unlike many other types of cancer, both men and women contract the disease in equal numbers and die at the same high rates. The risk for colon cancer begins to increase after age 40 and rises sharply at the ages of 50 to 55. At this point, the risk doubles with each succeeding decade, reaching a peak at age 75.

Primary Prevention of Polyps and Colorectal Cancer: The Role of Fiber

Consensus Statement

Cancer of the colon and rectum is a major public health problem that has received inadequate public attention. More than 130,000 men and women in the United States will be diagnosed with colorectal cancer this year, and many more will have colorectal polyps from which cancer may develop. Nearly 55,000 people die of colorectal cancer annually, and the disease ranks second only to lung cancer as a cause of cancer death in this country.

Appropriate screening can often detect early colorectal cancer when it is still curable, even before signs and symptoms occur. Colorectal polyps can also be detected and removed during screening, before cancer develops. In addition, dietary and other lifestyle changes may reduce the risk of developing colorectal polyps and cancer. Therefore, Americans should be provided the most up-to-date information available about this cancer and its prevention and should be encouraged to take appropriate actions to reduce their risk.

During the past 25 years, many population studies have strongly suggested that foods low in fat and rich in fiber help protect against colorectal cancer. In a recent well-conducted clinical trial, a low-fat diet supplemented by wheat bran prevented the development of large polyps (greater than/or equal to 10 mm). Animal experiments have shown a strong protective effect of wheat bran against tumors induced by cancer-causing agents.

A diet that is low in fat and high in whole grains, fruits, vegetables, and legumes (beans, peas) may reduce the occurrence of some types of cancer, particularly colorectal cancer. Eating foods that contain an adequate amount of fiber — at least 25 grams total fiber per day for most adults — particularly from wheat bran or whole wheat, is an important component of a healthy-lifestyle program to help prevent colorectal cancer. Other recommended lifestyle practices include regular exercise, appropriate limitation of total calorie intake, and avoidance of smoking and excessive consumption of alcohol. This program of primary prevention should be combined with adherence to evidence-based screening and surveillance guidelines for polyps and colorectal cancer to reduce the high rates of illness and death from this cancer. These dietary and lifestyle recommendations may also have a beneficial effect against other cancers and noncancerous diseases such as heart disease, diabetes, and obesity.

Moshe Shike, MD
Memorial Sloan-Kettering
Cancer Center
New York, NY

Sidney J. Winawer, MD
Memorial Sloan-Kettering
Cancer Center
New York, NY

John H. Bond, MD
VA Medical Center
Minneapolis, MN

Finlay Macrae, MD
Royal Melbourne Hospital
Melbourne, Australia

Robert J. Cousins, PhD
University of Florida
Gainesville, FL

Bandaru S. Reddy, PhD, DVM
American Health Foundation
Valhalla, NY

David L. Earnest, MD
University of Arizona Health
Sciences Center
Tucson, AZ

Joanne L. Slavin, PhD, RD
University of Minnesota
St. Paul, MN

David Kritchevsky, PhD
The Wistar Institute
Philadelphia, PA

Gary Williams, MD
American Health Foundation
Valhalla, NY

Joanne R. Lupton, PhD
Texas A & M University
College Station, TX

SOURCE Kellogg/American Health Foundation

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