The Effects of a High Legume Low Glycemic Index Diet on Insulin Resistance and Inflammation in Patients at High Risk for Colorectal Adenoma Recurrence
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 factor 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.
Analysis from the Polyp Prevention Trial (PPT), a multi-center, randomized trial of 1905
participants who had a colorectal adenoma, showed that legume consumption was significantly
associated with reduction of both adenoma recurrence and advanced adenoma recurrence.
Legumes are a rich source of dietary fibers and anti-inflammatory, anti-cancer
We are evaluating 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 consumed the above experimental diet and a control diet for
four weeks with a two week washout period between diets. 65 male participants were recruited
and randomized into four groups. A secondary objective is to assess whether these endpoints
change by IR status or a history of adenomas. In addition, potential fecal markers of CRC
risk are being 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.
Primary Purpose: Treatment
Evaluate the effects of a high legume, low glycemic index diet on serum C-reactive protein (CRP).
Matthew R Young, Ph.D.
National Cancer Institute (NCI)
United States: Federal Government
|Pennsylvania State University||Hershey, Pennsylvania 17033|