Clinical Trials Logo

Clinical Trial Summary

Low and very low carbohydrate diets, such as the Atkins' Diet, have recently gained attention for their potential health benefits from weight loss and have gained some scientific support from a growing number of studies. Benefits have been noted in relation to raised "good" cholesterol, lower "bad" cholesterol and triglycerides. Other studies have shown an advantage in substituting vegetable fat for carbohydrate in insulin resistant individuals and in some instances in type 2 diabetes where improvements were seen in "good" cholesterol and blood sugars. At the same time, our research have been exploring diets containing less processed carbohydrates and other components which in combination (portfolio diet) have a similar cholesterol lowering effect to drug therapy.

Therefore we wish to determine whether our cholesterol-lowering components (portfolio diet) should be incorporated into lower carbohydrate diets especially to preserve "good" cholesterol and lower "bad" cholesterol for decreasing the risk of heart disease.


Clinical Trial Description

All subjects will undergo two parallel 2-phase treatments. On one treatment, subjects will be placed on a low fat diet for one month (control run-in diet) and then for the second month will continue on the low- fat diet (i.e. low-MUFA) with the addition of the portfolio components. The order of these two phases will not be randomized. The other treatment will be similar to the above except that the background diet of the portfolio phase will be high in monounsaturated fat (high-MUFA). Subjects will be allocated randomly to either treatment. Diets will be metabolically controlled and all food will be provided at weekly intervals.

Subjects will come after a 12h overnight fast to the Risk Factor Modification Center at St. Michael's Hospital or the Department of Nutritional Sciences, University of Toronto immediately prior to commencement of each treatment phase and at weekly intervals during the course of each study period. Prior to the start of the study, subjects will be instructed on details of the study diet protocol. They will also be asked to maintain a constant level of physical activity throughout the course of the study. At all visits, body weight (in kg) will be obtained in indoor clothing, without shoes, and blood pressure will be taken twice in the dominant arm after subjects have been seated for at least 20 minutes. Height (in cm) will be recorded at the first visit. Throughout the study period, subjects will maintain the diet prescribed on their initial visit. At every other visit of each treatment phase, subjects will provide a fasting blood sample. The kinetic tests of lipoprotein metabolism will be performed during the 4th and 8th week of the study. At baseline and during the last week of each study phase, 24h urine collection and 12h breath hydrogen collections will be completed.

The measurement of apolipoprotein in vivo kinetics will be carried out using a primed-constant infusion of [D3]L-leucine. This protocol allows for the determination of the kinetics of all apolipoproteins simultaneously. Kinetics studies will be conducted in the constantly fed state where participants receive 1/30th of their daily energy requirements every half-hour for the whole duration of the test (15 hours). These methods are described in detail in previous publications from our group. Briefly, at 7am on the morning of the study, after a 12-hour overnight fast, participants will be admitted to the Toronto General Hospital Clinical Investigation Unit and two intravenous catheters (IV's) will be inserted, one into each forearm vein. One IV will be for infusion of the stable isotope described below and one for withdrawal of blood samples. After achieving a steady state (3hrs after the small half-hourly meals), subjects will first receive a bolus injection of 10 µmol/kg of body weight of [D3]L-leucine ([D3]L-leucine 98%, C/D/N Isotopes) dissolved in physiological saline (0.9% NaCl) and then a constant infusion of 10 µmol/kg/h of [D3]L-leucine for 12 hours via an intravenous line inserted into a left forearm vein. Blood samples will be collected at regular intervals (0, 1/2, 1, 2, 4, 6, 8, 10, 11, 12hrs). All lipoprotein subfractions will be separated by sequential ultracentrifugation and frozen thereafter at -80oC until they are processed for analysis. ;


Study Design

Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Treatment


Related Conditions & MeSH terms


NCT number NCT00430430
Study type Interventional
Source University of Toronto
Contact
Status Completed
Phase Phase 2
Start date April 2007
Completion date April 2009

See also
  Status Clinical Trial Phase
Recruiting NCT05654272 - Development of CIRC Technologies
Recruiting NCT05650307 - CV Imaging of Metabolic Interventions
Recruiting NCT04515303 - Digital Intervention Participation in DASH
Completed NCT04056208 - Pistachios Blood Sugar Control, Heart and Gut Health Phase 2
Recruiting NCT04417387 - The Genetics and Vascular Health Check Study (GENVASC) Aims to Help Determine Whether Gathering Genetic Information Can Improve the Prediction of Risk of Coronary Artery Disease (CAD)
Not yet recruiting NCT06211361 - Cardiac Rehabilitation Program in Patients With Cardiovascular Disease N/A
Not yet recruiting NCT06032572 - Evaluation of the Safety and Effectiveness of the VRS100 System in PCI (ESSENCE) N/A
Recruiting NCT04514445 - The BRAVE Study- The Identification of Genetic Variants Associated With Bicuspid Aortic Valve Using a Combination of Case-control and Family-based Approaches.
Enrolling by invitation NCT04253054 - Chinese Multi-provincial Cohort Study-Beijing Project
Completed NCT03273972 - INvestigating the Lowest Threshold of Vascular bENefits From LDL Lowering With a PCSK9 InhibiTor in healthY Volunteers N/A
Completed NCT03680638 - The Effect of Antioxidants on Skin Blood Flow During Local Heating Phase 1
Recruiting NCT04843891 - Evaluation of PET Probe [64]Cu-Macrin in Cardiovascular Disease, Cancer and Sarcoidosis. Phase 1
Completed NCT04083872 - Clinical Study to Investigate the Pharmacokinetic Profiles and Safety of Highdose CKD-385 in Healthy Volunteers(Fasting) Phase 1
Completed NCT04083846 - Clinical Study to Investigate the Pharmacokinetic Profiles and Safety of High-dose CKD-385 in Healthy Volunteers(Fed) Phase 1
Completed NCT03466333 - Postnatal Enalapril to Improve Cardiovascular fUnction Following Preterm Pre-eclampsia Phase 2
Completed NCT03693365 - Fluid Responsiveness Tested by the Effective Pulmonary Blood Flow During a Positive End-expiratory Trial
Completed NCT03619148 - The Incidence of Respiratory Symptoms Associated With the Use of HFNO N/A
Completed NCT04082585 - Total Health Improvement Program Research Project
Completed NCT05132998 - Impact of a Comprehensive Cardiac Rehabilitation Program Framework Among High Cardiovascular Risk Cancer Survivors N/A
Completed NCT05067114 - Solutions for Atrial Fibrillation Edvocacy (SAFE)