Low Glycemic Index Diet for Type 2 Diabetics

Low Glycemic Index Diets to Improve Glycemic Control and Cardiovascular Disease in Type 2 Diabetics

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.

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

Treatments:

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.

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)