Low Glycemic Index Diets vs. High Cereal Fibre Diets in Type 2 Diabetes

This study has been completed.
Information provided by:
University of Toronto
ClinicalTrials.gov Identifier:
First received: February 21, 2007
Last updated: December 1, 2008
Last verified: December 2008
Large observational studies have shown cereal fiber to protect from diabetes and heart disease. Despite the success of acarbose, an α-glucosidase hydrolase inhibitor, which lowers the glycemic index of foods containing starch, sucrose and maltodextrins, the use of diets containing low glycemic index foods still remains to be established. We will therefore provide otherwise healthy individuals with type 2 diabetes intensive counseling on food selection either to improve glucose control using high cereal fiber dietary strategies or low glycemic index foods. Studies will last 6 months with bloods taken for HbA1c, glucose and blood lipids. If the study shows a benefit for either or both diets then use of high fiber and/or low glycemic index foods in the diet may provide another potential way to improve glucose control and lower cholesterol levels in non-insulin dependent diabetes.

Condition Intervention Phase
Type 2 Diabetes
Cardiovascular Disease
Diet Therapy
Procedure: Low Glycemic Index diets
Procedure: High Cereal Fibre Diets
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effect of Low Glycemic Index Diets on Glucose Control in Non-Insulin Dependent Diabetics

Resource links provided by NLM:

Further study details as provided by University of Toronto:

Primary Outcome Measures:
  • Hemoglobin A1c
  • Serum Fructosamine
  • Fasting Glucose
  • Fasting Insulin

Secondary Outcome Measures:
  • serum FFA
  • C-peptide
  • CRP
  • IGF-I
  • IGFBP-3
  • Serum apo AI
  • apo B
  • apo Lp(a)
  • amino acids
  • Plasma lipids and lipoproteins (TG, LDL, HDL)
  • Oxidized LDL
  • Urinary creatinine
  • urea
  • Urinary C-peptide

Enrollment: 210
Study Start Date: September 2004
Study Completion Date: June 2007
Detailed Description:

Recruitment: Subjects will be recruited by placing advertisements in local newspapers and by distributing similar advertisements to the diabetes clinic and diabetes education programs.

Information Sessions: Approximately 1000 volunteers in groups of 10-30 with or without spouses will attend one of a number of evening information sessions run from the Risk Factor Modification Center at St. Michael's Hospital. During the sessions the exact nature of the study will be described and volunteers will have the opportunity to ask specific questions about the study and taste the high fiber and low glycemic index foods.

Screening: Potential subjects will then fill in and return to the investigators a detailed questionnaire concerning their medical history, medications (including vitamin, mineral and nutritional supplements) smoking habits, alcohol intake and exercise pattern and whether they are currently on a specific diet. Details will also be obtained concerning planned vacations. Those subjects deemed potentially eligible will be asked to give a fasting blood sample at the Risk Factor Modification Center. Individuals who meet the study criteria, are invited to return again to the Center. The principles of the diabetic diet which they are already expected to be following will be reinforced, which incorporate the key elements of an NCEP Step 2 diet (total calories from fat <30%, saturated fat <7%, polyunsaturated fat <10%, dietary cholesterol <200 mg/day).

All subjects will then be randomized to one 24-week treatment in a two-treatment parallel design.

Treatments: 1) low glycemic index dietary advice (e.g. to eat intact grain cereals, pumpernickel bread, parboiled rice, cracked wheat, pasta, peas, beans and lentils) 2) high cereal fiber diet. Background diets will be the subjects' diabetic diets, modified as above, which will conform to CDA and NCEP Step 2 guidelines. Diet histories will be recorded at weeks 0, 2, 4, 8, 12, 16 and 24. These diets will be assessed for consistency by the dietitian in the subject's presence. Where necessary, modifications in diet will be made to ensure weight maintenance. Compliance will be assessed by 7 day food records.

Duration: the study will consist of four months recruitment and patient selection, during which time estimation of individual caloric requirements will be performed, and 6 months treatment period

Study Details: Fasting blood samples are obtained at day zero and weeks 2, 4, 8, 12, 16 and 24 of each study period. Twenty-four hour urine for urinary C-peptide analyses will be obtained immediately prior to the beginning of the study and at the end of each 24-week treatment phase.

Palatability and satiety: subjects will record their ratings using a 9-point bipolar semantic scale at weekly intervals during each study phase.

Anthropometric measures: height at recruitment, waist and hip circumference, and body composition will be taken immediately prior to and at the end of each study phase. Body weight and blood pressure will be measured at clinic visits.

This study will help to indicate whether dietary advice can make a significant difference to glycemic control as has been the case with drug therapy to reduce postprandial glycemia.


Ages Eligible for Study:   21 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Men and postmenopausal women with type 2 diabetes treated with diet plus oral hypoglycemic agents (Sulfonylureas, Biguanides, Thiazolidinediones , and new secretagogues (Repaglinide)) at a stable dose for at least 3 months prior to starting the study
  • HbA1c between 6.5 and 8.0% at recruitment
  • living within a 40 km radius of St. Michael's Hospital
  • Diabetes diagnosed > 6 months prior to randomization

Exclusion Criteria:

  • diabetic complications: clinically significant gastroparesis, retinopathy, nephropathy, neuropathy, hepatic disease, or CHD (current clinically significant CHD e.g. unstable angina)
  • taking insulin or acarbose
  • smoking or significant alcohol intake (> 1 drink/day)
  • serum triglycerides > 4.0 mmol/L
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00438698

Canada, Ontario
St. Michael's Hospital
Toronto, Ontario, Canada, M5C 2T2
Sponsors and Collaborators
University of Toronto
Principal Investigator: David J.A. Jenkins, MD, PhD University of Toronto, St. Michael's Hospital
Study Director: Cyril W.C. Kendall, PhD University of Toronto, St. Michael's Hospital
  More Information

No publications provided by University of Toronto

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
ClinicalTrials.gov Identifier: NCT00438698     History of Changes
Other Study ID Numbers: REB 04-021, CIHR RCT#: 67894
Study First Received: February 21, 2007
Last Updated: December 1, 2008
Health Authority: Canada: Canadian Institutes of Health Research

Keywords provided by University of Toronto:
Type 2 Diabetes

Additional relevant MeSH terms:
Cardiovascular Diseases
Diabetes Mellitus, Type 2
Diabetes Mellitus
Endocrine System Diseases
Glucose Metabolism Disorders
Metabolic Diseases

ClinicalTrials.gov processed this record on December 01, 2015