The Effect of Plant-based Diets (Vegetarian and Vegan) on Endothelial Function and Atherogenic Parameters

Study Overview
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Brief Summary
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The investigators' hypothesis is that a plant-based diet may be beneficial if nutritional deficiencies will be corrected. The aims of the present proposal are to 1) study endothelial functions of subjects on well-defined vegetarian/vegan diets compared to age and sex matched omnivores (controls), and 2) study the differences in energy expenditure, body composition, overnight substrate utilization, blood work results, and levels of intracellular reactive oxygen species (ROS) and of adhesion molecules on the different diets.

Detailed Description
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The serious doubts about the nutritional adequacy of vegetarian diets in the past were essentially put to rest by recent studies that suggested that plant-based diets are healthy and associated with lower risk of several chronic diseases. Nevertheless, various nutritional deficiencies have been identified, and it has been shown that individuals who follow different types of vegetarian/vegan diets may not experience the same effects on their health. Working Hypothesis Vegetarian/vegan diets will promote protection against cardiovascular risk factors if supplemented with possibly deficient nutrients. There will a further protective effect and a greater number of differences between subjects following a vegetarian diet compared to those following a vegan diet. Higher energy expenditure and lower and different caloric intake will promote a favorable difference in body composition (lower body fat) via a different substrate utilization expressed in the measured respiratory quotient (RQ). Extra- and intracellular free radicals will be higher in subjects who adhere to vegetarian/vegan diets compared to omnivores. Aims of the study To study the effect of vegetarian/vegan diets on endothelial functions after correcting for modifying factors. To study the effect of the above-mentioned plant-based diets on carotid intima-media thickness. To study the differences in body composition, resting energy expenditure and over-night substrate utilization between the different diets. To study the intracellular ROS of subjects following different diets.

Conditions
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Other Endothelial Dystrophy

Intervention / Treatment
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* Device: Endo-pat 2000
* Device: carotid intima media thickness Ultrasound
* Device: Dexa- Bone densitometer & Bone ultrasonometer System


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: over 5 years' adherence to any type of diet age range 35-50 years BMI ≤32 Exclusion Criteria: smoking type I and II diabetes liver and kidney impairments cardiovascular diseases patients with tumors patients on medications which may affect cardiovascular parameters (including 5 phosphodiesterase inhibitors, beta blockers, ACE inhibitors and others) BMI >32 kg/m2.

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Endo-pat 2000|The endo peripheral arterial tonometry (PAT) provides an index of endothelial function in two forms: The reactive hyperemia index (RHI) is the post-to-preocclusion PAT signal ratio in the occluded side, normalized to the control side and further corrected for baseline vascular tone. The logarithm RHI (LnRHI) is s similar index as RHI after natural log transformation with a matched cutoff. LnRHI provides better double-sided distribution than RHI and one that is closer to normal distribution|
|Device: carotid intima media thickness Ultrasound|cIMT is the distance between the intimal-luminal interface and the medial-adventitial interface. It will be studied by B-mode ultrasonography of the extracranial carotid arteries. A duplex system with a 7-10 megahertz (MHz) linear array multi-frequency transducer will be used.|
|Device: Dexa- Bone densitometer & Bone ultrasonometer System|A means of measuring bone mineral density and body composition by a dual energy X-ray absorptiometry (DEXA) machine|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| carotid intima-media thickness (cIMT) | measure the differences in the thickness of the carotid between the different diet group | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| body composition | Measure the differences in body composition ( fat %, lean body mass) between the different diet groups | 1-year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vegetarian diet, vegan, cardiovascular diseases, endothelial function, carotid intima-media thickness