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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00438698
Recruitment Status : Completed
First Posted : February 22, 2007
Last Update Posted : December 16, 2015
Information provided by (Responsible Party):
David Jenkins, University of Toronto

Brief Summary:
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 or disease Intervention/treatment Phase
Type 2 Diabetes Cardiovascular Disease Other: Low Glycemic Index diet Other: High Cereal Fibre Diets Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 210 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effect of Low Glycemic Index Diets on Glucose Control in Non-Insulin Dependent Diabetics
Study Start Date : September 2004
Actual Primary Completion Date : June 2007
Actual Study Completion Date : June 2007

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Dietary Fiber

Arm Intervention/treatment
Experimental: Low Glycemic Index Diet
Diet with low glycemic index carbohydrates
Other: Low Glycemic Index diet
Diet to emphasize carbohydrate foods low in glycemic index

Active Comparator: High Fiber Diet
Diet with high cereal fibre choices
Other: High Cereal Fibre Diets
Diet to emphasize whole wheat carbohydrate cgoices

Primary Outcome Measures :
  1. Change in Hemoglobin A1c [ Time Frame: 6 months ]
  2. Change in Fasting Glucose [ Time Frame: 6 months ]

Secondary Outcome Measures :
  1. serum FFA [ Time Frame: 6 months ]
  2. C-peptide [ Time Frame: 6 months ]
  3. CRP [ Time Frame: 6 months ]
  4. IGF-I [ Time Frame: 6 months ]
  5. IGFBP-3 [ Time Frame: 6 months ]
  6. Serum apo AI [ Time Frame: 6 months ]
  7. apo B [ Time Frame: 6 months ]
  8. apo Lp(a) [ Time Frame: 6 months ]
  9. amino acids [ Time Frame: 6 months ]
  10. Plasma lipids and lipoproteins (TG, LDL, HDL) [ Time Frame: 6 months ]
  11. Oxidized LDL [ Time Frame: 6 months ]
  12. Change in Urinary creatinine [ Time Frame: 6 months ]
  13. urea [ Time Frame: 6 months ]
  14. Urinary C-peptide [ Time Frame: 6 months ]

Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years to 100 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00438698

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Canada, Ontario
St. Michael's Hospital
Toronto, Ontario, Canada, M5C 2T2
Sponsors and Collaborators
University of Toronto
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Principal Investigator: David JA Jenkins, MD, PhD University of Toronto, St. Michael's Hospital
Study Director: Cyril WC Kendall, PhD University of Toronto, St. Michael's Hospital
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: David Jenkins, Professor, University of Toronto Identifier: NCT00438698    
Other Study ID Numbers: REB 04-021
CIHR RCT#: 67894 ( Other Grant/Funding Number: CIHR )
First Posted: February 22, 2007    Key Record Dates
Last Update Posted: December 16, 2015
Last Verified: December 2015
Keywords provided by David Jenkins, University of Toronto:
Type 2 Diabetes
Additional relevant MeSH terms:
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Cardiovascular Diseases
Diabetes Mellitus, Type 2
Diabetes Mellitus
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases