Mediterranean Diet and the Metabolic Syndrome (MedDiet)

Laval University

Status: Completed

Conditions: Cardiovascular Disease

Treatments: Other: isocaloric diet; Other: free living conditions

Study type: Interventional

Funder types: Other

Identifiers

NCT00988650

INAF-2006-277

Details and patient eligibility

About

While there is now undisputable evidence relating elevated plasma low-density lipoprotein (LDL) cholesterol levels to an increased risk of coronary heart disease (CHD), it is being increasingly recognized that a significant proportion of CHD events occur in individuals characterized by a cluster of additional metabolic and physiological perturbations now defined as the metabolic syndrome. Epidemiological and clinical evidence have shown us that nutritional factors, often in conjunction with obesity, play a pivotal role in the pathophysiology of the metabolic syndrome. In that regard, accumulating evidence suggest that a Mediterranean-style diet (MedDiet) may beneficially modify several components of the metabolic syndrome including plasma triglycerides (TG) and high-density lipoprotein (HDL) cholesterol levels, insulin resistance, waist circumference and markers of vascular inflammation. However, the physiological mechanisms underlying the cardioprotective effects of the MedDiet on features of the metabolic syndrome and the importance of body weight reduction in maximizing these effects represent key issues that have yet to be investigated.

The general objective of the study is to investigate for the first time in a controlled feeding study the mechanisms and factors underlying the impact of the MedDiet, with and without weight loss on the dyslipidemic features of the metabolic syndrome.

Full description

The study has a duration of 35 weeks for each participant. Subjects will be first assigned to a North American control diet that they will consume for five weeks under isocaloric, weight-maintaining conditions. Participants will then consume the MedDiet for 5 weeks, again under isocaloric, weight-maintaining conditions. All foods will be provided to participants during these consecutive 5-week diets. Participants subsequently will then undergo a 20-week weight loss period in free-living conditions during which they will be given advice on how to create a 500 kcal deficit in their daily energy intake. The last phase of the study consists of a second 5-week MedDiet consumed under feeding, weight stabilizing conditions. Metabolic studies and CHD risk factor assessment will be performed at the end of each experimental diets. Metabolic studies include the measurement of in vivo kinetics of apolipoprotein (apo)B-containing lipoproteins including small dense LDL, apoCIII, HDL (apoAI) and C-reactive protein (CRP) as well as indirect measures of cholesterol absorption and synthesis.

Enrollment: 26 patients

Sex: Male

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Men from the Québec City metropolitan area with the metabolic syndrome based on the NCEP-ATP III definition (3 criteria or more see below):
• Waist circumference ≥ 102 cm
• Triglycerides ≥ 1.7 mmol/L
• HDL-cholesterol <= 1.04 mmol/L
• Systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 85 mmHg
• Fasting blood glucose ≥ 5.6 mmol/L
• Stable body weight (+/- 2 kg) for 6 months before the beginning of the study

Exclusion criteria

• Previous history of cardiovascular disease, type 2 diabetes and monogenic dyslipidemia
• Subjects taking medications for hyperlipidemia or hypertension
• Endocrine disorders
• Food allergies or aversion for specific components of the MedDiet
• Smokers
• Consummation excessive of alcohol (> 2 consummation/day)

Trial design

Primary purpose: Prevention

Allocation: Non-Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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26 participants in 4 patient groups

North American diet

Active Comparator group

Description:

Control North American diet for five weeks in isocaloric conditions

Treatment:

Other: isocaloric diet

Mediterranean diet

Experimental group

Description:

Mediterranean diet for five weeks in isocaloric conditions

Treatment:

Other: isocaloric diet

weight loss period

Experimental group

Description:

Weight loss period of 20-week (minimum 5% reduction in body weight)

Treatment:

Other: free living conditions

Weight stabilizing mediterranean diet

Active Comparator group

Description:

Mediterranean diet for five weeks in isocaloric weight stabilizing conditions

Treatment:

Other: isocaloric diet