Comparative Effects of 2 Diets in Veterans With the Metabolic Syndrome

VA Office of Research and Development46 enrolled

Overview

The purpose of the study is to examine the effects of 2 commonly used diets, a Mediterranean monounsaturated fatty acid enriched (MUFA) or AHA polyunsaturated (PUFA) enriched diet combined with the VA Managing Overweight/Obesity for Veterans Everywhere (MOVE!) program so as to determine which one is superior in reducing cardiometabolic risk factors associated with Metabolic Syndrome. The risk factors considered include lipids and lipoproteins, inflammatory markers such as CRP and adiponectin, endothelium-dependent flow-mediated vasodilatation (FMD) and the postprandial lipid responses to a meal. Cardiometabolic risk factors will be determined by measuring several cardiovascular risk associated parameters including: Biochemical measurements of lipids and inflammatory markers, body composition and VO2max (Specific Objective 1, Descriptive). Postprandial response to a meal challenge and endothelial vasoreactivity (FMD) assessed by BART (Specific Objective 2, Physiological). Determination of the effects on postheparin lipases and transfer protein activity, visceral adipose tissue (VAT) and homeostasis model assessment-estimated insulin resistance (HOMA-IR) (Specific Objective 3, Mechanistic)

The Metabolic Syndrome (MetS) is a common problem among Veterans and is associated with a greater likelihood of cardiovascular disease (CVD). The Mediterranean diet is the only popular diet that has been shown to reduce CVD event rates but the extent to which monounsaturated fatty acid (MUFA) or polyunsaturated fatty acid (PUFA) enrichment results in improvement in parameters of MetS is unresolved. Similarly, while low intensity exercise improves the CVD risk factor profile, there have been no comparative investigations comparing MUFA and PUFA enriched diets and exercise in patients with MetS that have extended beyond 1 year. Recently, the VA established the MOVE! program, a national weight management program designed to help Veterans lose weight. Using the VA promoted program, we will perform a systematic evaluation of the effects of dietary fat composition \[comparison between MUFA-enriched and PUFA enriched diet\] with MOVE!. We hypothesize that a MUFA-enriched diet consisting of antioxidant, lipid reducing and insulin sensitizing properties will be superior to the less palatable PUFA-enriched diet on improving cardiometabolic parameters associated with MetS. Specifically, the MUFA MOVE! program is expected to lead to greater improvements than the PUFA MOVE! program in body composition and aerobic fitness (Specific Aim 1), endothelial dependent flow mediated vasodilatation and the postprandial lipid response to a meal load (Specific Aim 2) and the mechanisms (lipolytic and lipid transfer protein activity, homeostasis model assessment-estimated insulin resistance) responsible for these effects (Specific Aim 3). Collectively, these studies will advance our understanding of mechanisms underlying the differential effects of MUFA and PUFA-enriched dietary regimens on cardiometabolic health and when combined with the MOVE! program, will provide new and useful information to Veterans (and the general public) interested in optimizing their diets for CVD disease prevention and improved vascular health.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: Presence of 3 or more of the following): * Waist circumference \>102 cm in men or \>88 cm women * Treated Hypertension or Untreated Blood pressure \>130/85 and \< 160/100 mm Hg * Treated Hyperglycemia or Untreated Fasting blood glucose (FBG) \>100 mg/dL (based on 2006 guidelines) * Treated Hyperlipidemia or Untreated Triglycerides \> 150 mg/dL * HDL-C \< 40 mg/dL men \< 50 mg/dL women Exclusion Criteria: * Decompensated heart failure (NYHA Class IV); * Severe Pulmonary disease (Unable to walk on a treadmill at 2.5 mph or greater); * Chronic renal insufficiency (Cr \> 2.5 mg/dL) * Treated diabetes mellitus with FBG \> 180 mg/dL or HbA1C \>9g % * Hematologic or malignant disorders * Treated SBP \>160 mmHg and/or DBP \> 95 mmHg ; * Treated TG \> 250 mg/dL * Use of systemic vasodilators (e.g., nitrates) * Morbid Obesity (BMI \> 50 kg/m2) * Endocrine (thyroid) or metabolic disorders (unless treated and under control) * Alcohol consumption greater than (2) 4-ounce glasses of table wine, (2) 12-oz bottles of beer or 2 shots of spirits in men or women * Active IV drug abuse within the past 6 months

Outcomes

Primary Outcomes

Weight Changes in Veterans With MetS.

Time frame: 6 months from Baseline

Secondary Outcomes

Endothelium-dependent FMD Assessed by the Brachial Artery Reactivity Test (BART) at Rest .

Ultrasonographic imaging of the brachial artery (BART) was used to assess endothelium-dependent flow-mediated vasodilation (FMD) in participants at rest. To do this,the blood pressure cuff is inflated to 200 mm Hg and kept inflated for 5 minutes. On immediate release of the cuff, the brachial artery was imaged within 1 minute after cuff release.