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Low Glycemic Index Diet for Type 2 Diabetics

This study has been completed.
Canadian Institutes of Health Research (CIHR)
Information provided by (Responsible Party):
David Jenkins, University of Toronto Identifier:
First received: February 3, 2010
Last updated: September 12, 2016
Last verified: September 2016
A low glycemic index diet may improve glycemic control and reduce plaque buildup in arteries of those with type 2 diabetes. Subjects will be randomly assigned to receive dietary advice on either a low glycemic index diet, or a high cereal fibre diet, for three years.

Condition Intervention Phase
Type 2 Diabetes Dietary Supplement: low glycemic diet instruction Dietary Supplement: high cereal fibre diet instruction Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Low Glycemic Index Diets to Improve Glycemic Control and Cardiovascular Disease in Type 2 Diabetics

Further study details as provided by David Jenkins, University of Toronto:

Primary Outcome Measures:
  • plaque volume [ Time Frame: 1, 3 years ]

Secondary Outcome Measures:
  • intima media thickness [ Time Frame: 0, 1, and 3 years ]
  • plaque morphology [ Time Frame: 0, 1, 3 years ]
  • HbA1c [ Time Frame: every 3 months for 3 years ]
  • serum lipids [ Time Frame: every 3 months for 3 years ]
  • blood pressure [ Time Frame: every 3 months for 3 years ]
  • serum fasting glucose [ Time Frame: creatinine, urea, and C-peptides in 24 hour urine collection ]
  • anthropometric measures (weight, waist and hip circumference) [ Time Frame: every 3 months for 3 years ]
  • retinal photography [ Time Frame: 1, 3 years ]
    ophthalmological assessment using fundoscopy

Enrollment: 169
Study Start Date: March 2010
Study Completion Date: August 2016
Primary Completion Date: July 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: low glycemic index, diabetic diet
low glycemic index, diabetic diet
Dietary Supplement: low glycemic diet instruction
Active Comparator: high cereal fibre, diabetic diet
high cereal fibre, diabetic diet
Dietary Supplement: high cereal fibre diet instruction

Detailed Description:

All subjects will be randomized to one 3-year treatment in a two-treatment parallel design.


  1. low glycemic index dietary advice (e.g. to eat intact grain cereals, parboiled rice, cracked wheat, pasta, peas, beans, lentils, and baked goods made from legume flour); or
  2. a high cereal fiber diet emphasizing whole grains. Duration: The study will consist of approximately two months of recruitment and patient selection, during which time estimation of individual caloric requirements will be assessed, and a 3 year treatment period assigned.

Study Details: Fasting blood samples are obtained at screening, week -2, and months 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33 and 36 each study period. HbA1c will be assessed on all visits. A carotid ultrasound (CUS) (screening, months 0, 12 and 36) and magnetic resonance imaging (MRI) (months 0, 12 and 36) technologies will be used to assess arterial wall thickening and changes in the nature of carotid plaques. 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 3 year treatment phase. At the end of the 3 year treatment period, subjects who wish to undertake the alternate treatment will be given appropriate instruction.


Ages Eligible for Study:   21 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

Men and women with type 2 diabetes who

  • are treated with oral hypoglycemic agents at a stable dose for at least 8 weeks
  • have a HbA1c in the range of 6.5 to 8.0% at screening and at the prestudy visit
  • have diabetes diagnosed >6 months
  • have maintained stable weight for 2 months (within 3%)
  • have a valid OHIP card and a family physician
  • if prescribed lipid medication, have taken a stable dose for at least 2 weeks
  • if prescribed blood pressure medication, have taken a stable dose for at least 1 week
  • can keep written food records, with the use of a digital scale

Exclusion Criteria: Individuals who

  • take insulin
  • take steroids
  • have GI disease (gastroparesis, celiac disease, ulcerative colitis, Crohn's Disease, IBS)
  • have had a major cardiovascular event (stroke or myocardial infarction) in the past 6 months
  • take warfarin (Coumadin)
  • have had major surgery in the past 6 months
  • have a major debilitating disorder
  • have clinically significant liver disease (AST or ALT > 130 U/L), excluding NAFL or NASH
  • have hepatitis B or C
  • have renal failure (high creatinine > 150 mmol/L)
  • have serum triglycerides ≥ 6.0 mmol/L
  • have a history of cancer, except non-melanoma skin cancer (basal cell, squamous cell)
  • have food allergies to study food components
  • have elevated blood pressure (> 145/90) unless approved by GP
  • have acute or chronic infections (bacterial or viral)
  • have chronic inflammatory diseases (e.g. rheumatoid arthritis, lupus; ulcerative colitis)
  • have other conditions which in the opinion of any of the investigators would make them unsuitable for the study
  • If HbA1c rises above 8.5% over two consecutive routine measurements, subjects will be referred back to their family doctors for an increase in anti hyperglycemic medications according to a predetermined protocol.
  • Any condition or circumstance which would prevent an individual from having an MRI (e.g. individuals with prostheses or metal implants, or those who are excessively claustrophobic)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01063374

Canada, Ontario
Sunnybrook Health Sciences Centre
Toronto, Ontario, Canada, M4N 3M5
Clinical Nutrition & Risk Factor Modification Centre, St. Michael's Hospital Health Centre
Toronto, Ontario, Canada, M5C 2T2
Sponsors and Collaborators
University of Toronto
Canadian Institutes of Health Research (CIHR)
Study Chair: David Mazer St. Michael's Hospital Research Ethics Board
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: David Jenkins, Principle Investigator, University of Toronto Identifier: NCT01063374     History of Changes
Other Study ID Numbers: 09-193
Study First Received: February 3, 2010
Last Updated: September 12, 2016
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No processed this record on September 19, 2017