Canola-Mediterranean Diet Study in T2DM

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.

Full Title of Study: “Canola Enriched Mediterranean Type Weight Loss Diet in Type 2 Diabetes”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Single (Investigator)
  • Study Primary Completion Date: December 14, 2016

Detailed Description

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.

Interventions

  • Behavioral: A canola oil enriched mediterranean diet
    • 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.
  • Behavioral: A high wheat fiber diet
    • 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

Arms, Groups and Cohorts

  • Experimental: A canola oil enriched mediterranean diet
    • Participants will be advised to consume, a low-carbohydrate diet (26-32% of calories), high in vegetable protein (28-32%) and fat (41-45%) with canola as the major component (10%). Carbohydrate sources will feature viscous fiber-containing foods (including psyllium cereal, oats and barley) and low-starch vegetables (emphasizing okra and eggplant) for the relatively limited amount of carbohydrate.
  • Active Comparator: A high wheat fiber diet
    • Participant will be advised to consume a high carbohydrate diet (58% carbohydrate, 16% protein and 25% fat) emphasizing whole wheat/whole grain cereals and increased high fiber alternatives, with fruits and vegetables.

Clinical Trial Outcome Measures

Primary Measures

  • change in HbA1c
    • Time Frame: Measured at weeks -2, 0, and then at weeks 8, 10 and 12
    • 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

Secondary Measures

  • 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
    • Time Frame: At weeks -1 and 12
    • Measurement will be done using a non-invasive SpaceLabs 90217 Ambulatory BP monitor
  • diet history
    • Time Frame: At weeks 0, 2, 4, 8, 10 and 12
    • 7-day food records brought in at weeks 0, 2, 4, 8, 10 and 12 will be analyzed for macro and micro nutrient intakes.
  • C-reactive protein
    • Time Frame: At weeks 0 and 12
  • Cholesterol absorption
    • Time Frame: At weeks -1 and 12
    • 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.
  • change in LDL particle size
    • Time Frame: Weeks 0 and 12
    • LDL particle size at weeks 0 and 12 will be determined by assessing their electrophoretic characteristics obtained by non-denaturing polyacrylamide gradient (2-16%) gel electrophoresis of serum
  • urinary analyses
    • Time Frame: week 0 and week 12
    • 24 hr urine samples will be analyzed for creatinine, urea, C-peptide, minerals, electrolytes and other dietary biomarkers

Participating in This Clinical Trial

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

Gender Eligibility: All

Minimum Age: 21 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Unity Health Toronto
  • Collaborator
    • University of Toronto
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • David J Jenkins, MD, Principal Investigator, St. Michael’s Hospital / University of Toronto
    • Cyril Kendall, PhD, Study Director, University of Toronto
    • Vladimir Vuksan, PhD, Study Director, Unity Health Toronto
    • Peter Jones, PhD, Study Director, University of Manitoba
    • Benoit Lamarche, PhD, Study Director, Laval University

References

Alhassan S, Kim S, Bersamin A, King AC, Gardner CD. Dietary adherence and weight loss success among overweight women: results from the A TO Z weight loss study. Int J Obes (Lond). 2008 Jun;32(6):985-91. doi: 10.1038/ijo.2008.8. Epub 2008 Feb 12.

Anderson JW, Randles KM, Kendall CW, Jenkins DJ. Carbohydrate and fiber recommendations for individuals with diabetes: a quantitative assessment and meta-analysis of the evidence. J Am Coll Nutr. 2004 Feb;23(1):5-17. doi: 10.1080/07315724.2004.10719338.

Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Marko R, Katorza E, Thiery J, Fiedler GM, Bluher M, Stumvoll M, Stampfer MJ; Dietary Intervention Randomized Controlled Trial (DIRECT) Group. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med. 2008 Jul 17;359(3):229-41. doi: 10.1056/NEJMoa0708681. Erratum In: N Engl J Med. 2009 Dec 31;361(27):2681.

Jenkins DJ, Wong JM, Kendall CW, Esfahani A, Ng VW, Leong TC, Faulkner DA, Vidgen E, Greaves KA, Paul G, Singer W. The effect of a plant-based low-carbohydrate ("Eco-Atkins") diet on body weight and blood lipid concentrations in hyperlipidemic subjects. Arch Intern Med. 2009 Jun 8;169(11):1046-54. doi: 10.1001/archinternmed.2009.115. Erratum In: Arch Intern Med. 2009 Sep 14;169(16):1490.

Guariguata L, Whiting D, Weil C, Unwin N. The International Diabetes Federation diabetes atlas methodology for estimating global and national prevalence of diabetes in adults. Diabetes Res Clin Pract. 2011 Dec;94(3):322-32. doi: 10.1016/j.diabres.2011.10.040. Epub 2011 Nov 17.

Kris-Etherton P, Eckel RH, Howard BV, St Jeor S, Bazzarre TL; Nutrition Committee Population Science Committee and Clinical Science Committee of the American Heart Association. AHA Science Advisory: Lyon Diet Heart Study. Benefits of a Mediterranean-style, National Cholesterol Education Program/American Heart Association Step I Dietary Pattern on Cardiovascular Disease. Circulation. 2001 Apr 3;103(13):1823-5. doi: 10.1161/01.cir.103.13.1823. No abstract available.

Sacks FM, Bray GA, Carey VJ, Smith SR, Ryan DH, Anton SD, McManus K, Champagne CM, Bishop LM, Laranjo N, Leboff MS, Rood JC, de Jonge L, Greenway FL, Loria CM, Obarzanek E, Williamson DA. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. N Engl J Med. 2009 Feb 26;360(9):859-73. doi: 10.1056/NEJMoa0804748.

Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972 Jun;18(6):499-502. No abstract available.

Jenkins DJ, Wong JM, Kendall CW, Esfahani A, Ng VW, Leong TC, Faulkner DA, Vidgen E, Paul G, Mukherjea R, Krul ES, Singer W. Effect of a 6-month vegan low-carbohydrate ('Eco-Atkins') diet on cardiovascular risk factors and body weight in hyperlipidaemic adults: a randomised controlled trial. BMJ Open. 2014 Feb 5;4(2):e003505. doi: 10.1136/bmjopen-2013-003505.

Gremaud G, Piguet C, Baumgartner M, Pouteau E, Decarli B, Berger A, Fay LB. Simultaneous assessment of cholesterol absorption and synthesis in humans using on-line gas chromatography/ combustion and gas chromatography/pyrolysis/isotope-ratio mass spectrometry. Rapid Commun Mass Spectrom. 2001;15(14):1207-13. doi: 10.1002/rcm.365.

Clinical trials entries are delivered from the US National Institutes of Health and are not reviewed separately by this site. Please see the identifier information above for retrieving further details from the government database.

At TrialBulletin.com, we keep tabs on over 200,000 clinical trials in the US and abroad, using medical data supplied directly by the US National Institutes of Health. Please see the About and Contact page for details.