Canola-Mediterranean Diet Study in T2DM

Unity Health Toronto164 enrolled

Overview

The purpose of the study is to assess whether a Mediterranean-type weight-loss diet, enriched with canola oil, high in plant protein, and low in carbohydrates will produce blood sugar control, reduce coronary heart disease (CHD) risk factors and maximize weight loss, better than conventional higher carbohydrate diets in overweight diabetic patients.

The investigators plan to assess the effects of increasing both canola oil and plant protein foods while reducing carbohydrate intake in the context of a Mediterranean type diet on weight loss, glycemic control and cardiovascular risk factors in type 2 diabetes. Obesity rates in Western nations have shown a dramatic rise in the last 20 years and diabetes rates have doubled, a trend which is predicted to be repeated over the next 20 years. In Canada the predicted cost to the healthcare system in only 7 years will rise to $17 billion. Weight loss diets (such as Atkins, Eddies, South Beach and Zone) emphasizing carbohydrate restriction have become increasingly popular for the prevention and treatment of diabetes. As a result, lower carbohydrate diets are being selected by health conscious members of the general population including those with diabetes. Because such diets in effect promote a high intake of protein from animal sources, even in the presence of weight loss, serum cholesterol levels rise due to increased cholesterol and saturated fat intake; and a further rise in serum lipids is likely to occur in the long term when weight loss has ceased. On the other hand, lower carbohydrate dietary patterns that are higher in plant rather than animal fat and proteins have been associated with improved blood lipids and reduced risk of heart disease and type 2 diabetes. The investigators have therefore planned a study in which a weight reducing low carbohydrate, Mediterranean type diet that is high in plant proteins and canola oil will be compared to a weight reducing high cereal fibre diet in a 3 month study. 150 overweight and obese participants with type 2 diabetes will be randomized to one of 2 treatments. Study visits will be as follows: weeks -2, 0 (for randomization), 2, 4, 8, 10 and 12. Body measurements, blood pressure and blood samples will be taken at each visit except week 2. The week 2 visit will be mainly for reinforcement of dietary advice; also body weight will be measured and blood drawn for fast glucose and HbA1c. Diet records will be reviewed at all visits. 24 hour urine samples will be collected at week 0 and week 12. On completion of the 12 week study, participants will be given the option of continuing on the same diet or trying the opposite diet for a further 12 weeks. Visits will be every 4 weeks for a total of 3 visit. Body measurements, blood pressure and blood samples will be taken during these visits as in the initial 12 week study.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

164

Conditions

Type 2 Diabetes Obesity Overweight Cardiovascular Diseases

Interventions

A canola oil enriched mediterranean dietBEHAVIORAL

The diet will be provided at 60% of calories estimated for stable body weight to encourage weight loss. A high protein canola oil-enriched test bread will be provided as a supplement.

A high wheat fiber dietBEHAVIORAL

The diet will be provided at 60% of calories estimated for stable body weight to encourage weight loss. A whole wheat control bread will be provided as a supplement to participants

Eligibility

Sex: ALLMin age: 21 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Men and women with type 2 diabetes diagnosed for more than 6 months * BMI \>27 (non-Asians); BMI \>25 (Asians) * HbA1c between 6.5% and 8.5% at screening, and at the preparation visit before starting diet * on a stable prescribed dose of oral diabetes medication for at least 2 months * on a stable dose of lipid medication for at least 2 weeks, if prescribed * on a stable dose of blood pressure medication for at least 1 week, if prescribed * have a family physician * can keep written food records, with the use of a digital scale Exclusion Criteria: Individuals with the following characteristics/conditions will be excluded * on insulin * on steroids * on warfarin (Coumadin) * GI disease (gastroparesis, celiac, colitis, Crohn's disease, Inflammatory Bowel Syndrome) * history of cancer, except non-melanoma skin cancer (basal cell, squamous cell) * major cardiovascular event (stroke, myocardial infarction) in past 6 months * major surgery in past 6 months * major debilitating disorder * liver disease (AST or ALT\> 3x the upper limit of normal) except non-alcoholic fatty liver (NAFL) disease or non-alcoholic steatohepatitis (NASH). * hepatitis B or C * renal failure (creatinine \> 150 mmol/L) * serum triglycerides \>4.5mmol/L * acute or chronic infections (bacterial or viral) * chronic inflammatory diseases (e.g. lupus, ulcerative colitis) * blood pressure \>145/90, unless approved by their family physician * alcohol consumption \>2 drinks/d * food allergies to wheat, canola, or other study food components * any condition determined by the investigators to make the subject unsuitable for the study

Locations (3)

Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba

Winnipeg, Manitoba, Canada

Risk Factor Modification Centre, St. Michael's Hospital

Toronto, Ontario, Canada

Institute of Nutraceuticals and Functional Foods, Laval University

Québec, Quebec, Canada

Outcomes

Primary Outcomes

change in HbA1c

The baseline HbA1c will be the average HbA1c of weeks -2 and week 0. The end HbA1c will be the average HbA1c of weeks 8, 10 and 12. Change will be the difference between the end and baseline values

Time frame: Measured at weeks -2, 0, and then at weeks 8, 10 and 12

Secondary Outcomes

Change in body weight

Time frame: baseline (week 0) and end (week 12)

blood glucose

Time frame: At weeks 0, 2, 4, 8, 10 and 12

Serum lipids: total cholesterol, LDL-chol, HDL-chol and Triglycerides

Time frame: At weeks 0, 4, 8, 10 and 12

Blood pressure

Time frame: At weeks 0, 4, 8, 10 and 12

24-hour Ambulatory blood pressure profile

Measurement will be done using a non-invasive SpaceLabs 90217 Ambulatory BP monitor

Time frame: At weeks -1 and 12

diet history

7-day food records brought in at weeks 0, 2, 4, 8, 10 and 12 will be analyzed for macro and micro nutrient intakes.

Time frame: At weeks 0, 2, 4, 8, 10 and 12

C-reactive protein

Time frame: At weeks 0 and 12

Cholesterol absorption

This is an optional sub-study that will be carried out prior to the first and last weeks of the 12 week study. On day 1 (a Monday) of the week -1 and last weeks of the study after an overnight 12hr fast, blood will be drawn and participants will be asked to ingest 75mg of the stable carbon isotope \[3, 4-13C\] cholesterol dissolved in 5g of margarine and spread on half of an English muffin. Subsequent blood draws will be taken after an overnight 12hr fast, at 48 h (a Wednesday) and 72 h (a Thursday) after ingestion of the labeled cholesterol.

Data from ClinicalTrials.gov

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