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Sponsored by: |
National Cancer Institute (NCI) |
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Information provided by: | National Institutes of Health Clinical Center (CC) |
ClinicalTrials.gov Identifier: | NCT00339469 |
This study, sponsored by the National Cancer Institute and Penn State University, will examine how a diet high in legumes (dried beans) influences risk factors for colon cancer and polyps. Many scientists believe that colon and rectal cancers develop from polyps (tumors of the lining of the large bowel). This study will test whether a high-legume diet can reduce levels of certain factors (blood insulin, blood glucose, and markers of inflammation such as C-reactive protein) that at elevated levels are known to increase the risk of colorectal polyps and colon cancer.
Healthy men between 35 and 75 years of age may be eligible for this study, conducted at Penn State University in University Park, Pennsylvania. Candidates are screened with blood tests and measurements of height, weight, and blood pressure. All candidates must have had a colonoscopy within 2 years of entering the study. They may or may not have had adenomas and may or may not be insulin-resistant. Candidates must not have cancer, heart disease, kidney disease, diabetes, or other serious medical condition, and they must have no history of colorectal cancer, polyp removal, bowel surgery, polyposis syndrome, or inflammatory bowel disease. Participants undergo the following tests and procedures:
Condition | Intervention | Phase |
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Adenomas Colorectal Adenoma Colon Adenomas |
Behavioral: Legume Diet |
Phase II |
Study Type: | Interventional |
Study Design: | Treatment |
Official Title: | The Effects of a High Legume Low Glycemic Index Diet on Insulin Resistance and Inflammation in Patients at High Risk for Colorectal Adenoma Recurrence. |
Estimated Enrollment: | 68 |
Study Start Date: | August 2005 |
Clinical, epidemiological, and molecular studies provide compelling evidence that most colorectal cancers arise from adenomas. The epidemiology of adenomas closely resembles that of colorectal cancer itself, and prevention of adenomas will most likely prevent colorectal cancer. Insulin resistance and type 2 diabetes are emerging as significant risk factors for colorectal (CRC) cancer and adenomas. Insulin resistance is defined as impaired biological response to the action of insulin. It is characterized by compensatory hyperinsulinemia and is associated with increased risk for Type 2 diabetes. C-peptide, a marker of insulin production, is elevated in IR and is also a risk for CRC. Both insulin resistance and colorectal cancer are increasingly recognized as chronic, low-level, inflammatory states. C-reactive protein (CRP), an acute phase protein and a sensitive marker of sub-clinical inflammation, is a risk factor for both IR and CRC.
The Polyp Prevention Trial (PPT) was a four year large multi-center, randomized trial of 1905 participants who had a colorectal adenoma removed within six months prior to randomization. There was no effect of a comprehensive dietary intervention-counseling of patients and assignment to a diet low in fat and high in fiber, fruits, and vegetables- on the recurrence of colorectal adenomas. In a post trial analysis of the data, legume consumption was significantly associated with both adenoma recurrence and advanced adenoma recurrence. Legumes are a rich source of fermentable dietary fibers which are precursors of luminal butyrate, a compound with anti-inflammatory and anti-neoplastic properties. In addition, legumes have a low glycemic index (GI). GI is defined as the incremental area under the blood glucose curve induced by a specific carbohydrate-containing food. A limited number of epidemiologic studies show a low GI diet is associated with a reduced risk of CRC, and decreased serum CRP.
We propose to evaluate the effects of a legume enriched, low glycemic index, high fermentable fiber diet, on CRP, (a measure of inflammation) and C-peptide (a measure of insulin resistance) in participants with four possible combinations of the risk factors insulin resistance and history of adenomatous polyps. In a randomized crossover design controlled feeding study each participant will consume the above experimental diet and a control diet for four weeks with a two week washout period between diets. We will recruit and randomize a total of 68 male participants in each of the four groups (17 each): 1. previous history of adenomas and IR; 2. previous history of adenomas without IR; 3. IR with no history of adenomas; and 4. non-IR and no history of adenomas. In addition, potential fecal markers of CRC risk will be measured to assess changes in gastrointestinal inflammation, including mRNA from exfoliated fecal colonocytes. To our knowledge this is the first controlled feeding study: 1. to examine the effects of legumes or a low GI diet on markers of inflammation; 2. to compare the effects of a dietary intervention on patients with a history of colon adenomas with or without IR; and 3. to measure the effects of dietary changes in human intestinal gene expression profiles using exfoliated colonocytes.
Ages Eligible for Study: | 35 Years to 75 Years |
Genders Eligible for Study: | Male |
Accepts Healthy Volunteers: | No |
INCLUSION CRITERIA
Subjects have a BMI 25.0-34.9 kg/m(2)
Group 1 (adenoma, IR)
Subjects are insulin resistance as determined by the Homeostasis Assessment Model (HOMA-IR), a mathematical model which allows values for insulin sensitivity and beta-cell function (expressed as percent of normal) to be obtained from simultaneous fasting plasma glucose and fasting insulin. HOMA-IRA is calculated by fasting serum insulin (FI in uU/mL); fasting glucose (FG in mmol/L) / 22.5 or HOMA-IR = FIxFG/22.5 (188). Values greater than or equal to 2.61 are considered insulin resistant
Group 2 (adenomas, non IR)
Subjects are not insulin resistance as determined by HOMA-IR.
Group 3 (no adenoma, IR)
Subjects are insulin resistant as determine by HOMA-IR.
Group 4 (no adenoma, non IR)
EXCLUSION CRITERIA
All Subjects
Potential participants should not be regularly using the following preparations:
Participants will be asked not to use any supplements (including herbal and alternative therapies) other than a regular multi-vitamin/mineral while participating in the study. While we ask subjects to stop use of OTC medications during the study, we recognize that there may be occasional use of OTC analgesics during the course of the study. At least under some circumstances we will permit the use of OTC analgesics, which is otherwise listed as an exclusion criteria. At their scheduled blood draws, we will ask subjects to report any use of OTC medications during the past week. Participants will also be asked to limit their use of alcohol during the study to less than or equal to 2 drinks/week.
Study ID Numbers: | 999905215, 05-C-N215 |
Study First Received: | June 19, 2006 |
Last Updated: | September 19, 2008 |
ClinicalTrials.gov Identifier: | NCT00339469 |
Health Authority: | United States: Federal Government |
Controlled diet C-reactive Protein Colon Satiety Fecal Colonocytes |
Insulin Resistance Adenoma Insulin Recurrence |
Colorectal Neoplasms Neoplasms, Glandular and Epithelial Inflammation |
Neoplasms Neoplasms by Histologic Type |