Impact of Meal Fatty Acids on Postprandial Vascular Reactivity

Study Overview
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Brief Summary
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Cardiovascular disease (CVD) is the leading cause of death in women. Premenopausal women have a lower risk of CVD compared with men of a similar age. However, the incidence of CVD increases greatly after the menopause. The risk of heart disease is strongly associated with the health of an individual's blood vessels. It is thought that changes to the type of fat the investigators eat in their diet may affect the normal functioning and elasticity of the blood vessels, as well as affect cholesterol levels in the blood. Types of fat in the diet include monounsaturated fats (found mainly in olive oil), n-6 polyunsaturated fats (found mainly in sunflower oil) and saturated fats (found mainly in dairy products, such as butter and cheese). Since the investigators are in the fed (or postprandial) state for up to 18 hours of the day, it is important to see how these different fats affect the investigators blood vessels and blood fats over the course of the day after eating a meal. The aim of this study is to determine how consuming meals rich in saturated fats, n-6 polyunsaturated fats or monounsaturated fats influence the normal functioning and elasticity of the blood vessels throughout the day in postmenopausal women. A secondary aim is to determine the effects of these different dietary fats on a range of accepted heart disease risk markers including circulating levels of fats (lipids) and glucose in the blood.

Official Title
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The Acute Effects of Meals Rich in Saturated, Monounsaturated and n-6 Polyunsaturated Fatty Acids on Vascular Function

Conditions
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Cardiovascular Disease

Intervention / Treatment
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* Dietary Supplement: Saturated fat
* Dietary Supplement: Monounsaturated fat
* Dietary Supplement: n-6 polyunsaturated fat


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Postmenopausal (not menstruated for at least 1 year) Plasma triacylglycerol (TAG) between 0.8 and 4.0 mmol/l Body mass index (BMI) between 18-35 kg/m2 Total cholesterol (TC): <8 mmol/l Systolic blood pressure <160 mmHg and diastolic blood pressure <100 mmHg Non-smoker Exclusion Criteria: Having suffered a myocardial infarction/stroke in the past 12 months Diabetic (diagnosed as fasting blood glucose >7 mmol/l) or suffering from other endocrine disorders Suffering from renal or bowel disease or have a history of cholestatic liver or pancreatitis On drug treatment for hyperlipidaemia, hypertension, inflammation or hypercoagulation History of alcohol abuse On hormone replacement therapy (HRT) Planning or on a weight reducing regime Taking nutritional supplements (e.g. fish oil, calcium) Anaemic: haemoglobin <11.5 g/dl

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Female

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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Meal rich in saturated fats<br>Subjects are asked to consume a breakfast (0 min) and lunch (330 min) rich in saturated fats | Dietary Supplement: Saturated fat<br> <br> * Other names: SFA;|
| Experimental: Meal rich in monounsaturated fats<br>Subjects are asked to consume a breakfast (0 min) and lunch (330 min) rich in monounsaturated fats | Dietary Supplement: Monounsaturated fat<br> <br> * Other names: MUFA;|
| Experimental: Meal rich in n-6 polyunsaturated fats<br>Subjects are asked to consume a breakfast (0 min) and lunch (330 min) rich in n-6 polyunsaturated fats | Dietary Supplement: n-6 polyunsaturated fat<br> <br> * Other names: n-6 PUFA;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in vascular reactivity measured by flow-mediated dilatation (FMD) |  | Acute study: measured at 0 (baseline), 180, 300 and 420 min | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in vascular reactivity measured by laser Doppler imaging with iontophoresis of acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) |  | Acute study: measured at 0 (baseline), 240 and 450 min | 
| Change from baseline in plasma lipids (primarily triacylglycerol, apolipoprotein B and non-esterified fatty acids) |  | Acute study: taken at 30 min intervals between 0 min (baseline) and 480 min | 
| Change from baseline in arterial stiffness measured by digital volume pulse (stiffness index and reflection index) |  | Acute study: taken at 0 (baseline), 240 amd 450 min | 
| Change from baseline in blood pressure (systolic blood pressure, diastolic blood pressure and pulse pressure) |  | Acute study: taken at 0 (baseline), 240 and 450 min | 
| Change from baseline in markers of insulin resistance (glucose, insulin, indices of insulin resistance/sensitivity) |  | Acute study: taken at 30 min intervals between 0 min (baseline) and 480 min | 
| Change from baseline in nitric oxide (total plasma nitrates and nitrites) |  | Acute study: 0 (baseline), 180, 300 and 420 min | 
| Change from baseline in plasma markers of endothelial activation (e.g. E-selectin, P-selectin, vascular cell adhesion molecule (VCAM-1)) |  | Acute study: 0 (baseline), 180, 300 and 420 min | 
| Change from baseline in plasma phospholipid fatty acid composition |  | Acute study: 0 (baseline), 180, 300 and 420 min | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fatty acids, Cardiovascular disease, Vascular function, Blood pressure, Plasma lipids, Insulin resistance, Endothelial activation