Featured Research

from universities, journals, and other organizations

Dietary Changes Don't Prevent Recurrent Polyps, Eight-Center Study Shows

Date:
April 24, 2000
Source:
Wake Forest University Baptist Medical Center
Summary:
The Polyp Prevention Trial, one of the largest studies aimed at preventing colon cancer by dietary change, came to an unexpected conclusion: "The Polyp Prevention Trial provided no evidence that adopting a low-fat, high-fiber fruit- and vegetable-enriched eating plan reduces the incidence of colorectal cancer," according to a report in today's (April 20) issue of the New England Journal of Medicine.

The Polyp Prevention Trial, one of the largest studies aimed at preventing colon cancer by dietary change, came to an unexpected conclusion:

"The Polyp Prevention Trial provided no evidence that adopting a low-fat, high-fiber fruit- and vegetable-enriched eating plan reduces the incidence of colorectal cancer," according to a report in today's (April 20) issue of the New England Journal of Medicine.

The study, which involved Wake Forest University Baptist Medical Center and seven other centers, tested the effect of diet on recurrence of intestinal polyps. Polyps are considered a precursor of cancer of the colon. The research team had hoped that the study would establish the importance of diet in preventing this cancer.

Instead, for people who already have had polyps, the research team is now recommending regular screening and colonoscopies, according to Elaine Lanza, Ph.D., of the National Cancer Institute, national co-principal investigator.

"This has led us in other directions in preventing colon cancer," said M. Robert Cooper, M.D., principal investigator at Wake Forest and professor of internal medicine (hematology/oncology).

Besides Medical Center patients, Cooper's team recruited participants from private practicing gastroenterologists in Forsyth County, Charlotte, Greensboro, Burlington and Statesville. Half the patients were assigned to the dietary group, half to a control group.

The diet included five to eight servings of fruits and vegetables a day, at least 18 grams of dietary fiber a day for every 1000 calories, and no more than 20 percent of daily calories from fat. The participants on the diet also were assigned a nutritionist for counseling and attended more than 50 hours of individual and group dietary counseling sessions.

The control group got general dietary guidelines from the National Dairy Council -- but no additional nutritional or behavioral help. The trial lasted for four years. Doctors repeated colonoscopies to look for recurring polyps at the end of the first and fourth years.

The participants seem to have followed the diet. The investigators report that the dietary group consumed 9.7 percent fewer calories from fat than the control group and increased their fiber intake by nearly 75 percent. Servings of fruits and vegetables increased by about two-thirds in the intervention group, while control group participants only had a slight increase. Consumption of red meat dropped by about 20 percent in the diet group but only 2.5 percent in the control group. Use of whole grains increased 38 percent in the diet group, but declined in the control group.

Nonetheless, polyps recurred in 39.7 percent of the diet group and 39.5 percent of the control group, a statistical tie.

"We also found no effect of the dietary intervention on either large or advanced lesions," the group reported.

The researchers analyzed a long list of possible explanations, including such considerations that "dietary adherence was less than it appeared," or "the reported changes in intake of fat, fiber and fruits and vegetables were real - but not big enough" or "we intervened too late in life."

They concluded, "The plausibility of several alternative explanations for the…findings argues against concluding definitively that dietary change is ineffective."

Other centers included Memorial Sloan-Kettering Cancer Center in New York, the State University of New York at Buffalo, the University of Pittsburgh, the University of Utah in Salt Lake City, Walter Reed Army Medical Center in Washington, the VA Medical Center in Hines, Ill., and the Kaiser Foundation Research Institute in Oakland, Calif.


Story Source:

The above story is based on materials provided by Wake Forest University Baptist Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

Wake Forest University Baptist Medical Center. "Dietary Changes Don't Prevent Recurrent Polyps, Eight-Center Study Shows." ScienceDaily. ScienceDaily, 24 April 2000. <www.sciencedaily.com/releases/2000/04/000421083707.htm>.
Wake Forest University Baptist Medical Center. (2000, April 24). Dietary Changes Don't Prevent Recurrent Polyps, Eight-Center Study Shows. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2000/04/000421083707.htm
Wake Forest University Baptist Medical Center. "Dietary Changes Don't Prevent Recurrent Polyps, Eight-Center Study Shows." ScienceDaily. www.sciencedaily.com/releases/2000/04/000421083707.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins