Effect of Beetroot Juice on Blood Pressure Regulation in Post Menopausal Women

Study Overview
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Brief Summary
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In this study the investigators will test the hypothesis that acute consumption of inorganic nitrate (supplied in concentrated beetroot juice) reduces artery stiffness and resting blood pressure, and lessens the rise in blood pressure during handgrip exercise in postmenopausal women. Understanding and improving artery function and blood pressure regulation in women is important because they undergo accelerated arterial stiffening after menopause and have much larger increases in blood pressure when they exercise compared with either premenopausal women or men of similar age.

Detailed Description
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Postmenopausal women have stiff central arteries and exaggerated blood pressure (BP) responses during exercise compared with either premenopausal women or men of similar age. Arterial stiffness and exaggerated BP responses to exercise are prognostic for heart wall thickening, future hypertension, adverse cardiovascular events, and mortality. Previous studies have reported that acute consumption of nitrate-rich beetroot juice can lower resting and exercising BP responses in older adults. However, these studies included both sexes and did not compare the effects of beetroot juice to a nitrate-depleted placebo (a true control). Thus, the potential BP lowering effects of nitrate supplementation per se have not been established in postmenopausal women. The present study examines the acute (single dose) effects of nitrate-rich beetroot juice on resting hemodynamics (peripheral and central BP, arterial wave properties, etc), and physiological responses to handgrip exercise in metabolically healthy post-menopausal women.

Official Title
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Acute Blood Pressure-lowering Effects of Beetroot Juice in Postmenopausal Women With and Without Hypertension

Conditions
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Postmenopausal Women

Intervention / Treatment
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* Drug: Beetroot juice
* Drug: Beetroot juice placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Resting systolic blood pressure less than or equal to 160 mmHg Resting diastolic blood pressure less than or equal to 100 mmHg Exclusion Criteria: Overt cardiovascular, metabolic, hematologic, pulmonary, renal, musculoskeletal, and/or neurological disease(s) Users of any tobacco and/or nicotine products (smokers, chewing tobacco, nicotine-containing patches/gum, smokeless cigarettes) Body mass index greater than 35 Total cholesterol greater than 239 mg/dl LDL cholesterol greater than 159 mg/dl Fasting blood triglycerides greater than 199 mg/dl Fasting blood glucose greater than 109 mg/dl and HbA1c greater than 6.0% Individuals currently taking any of the following medications: blood pressure lowering medication (e.g., beta blockers, ACE inhibitors, angiotensin antagonists, calcium channel blockers, diuretics) lipid-lowering medication (e.g., statins) nitrates (e.g. nitroglycerin) for angina phosphodiesterase inhibitors (e.g., Viagra) anti-inflammatory drugs Individuals currently taking hormone replacement therapy

Ages Eligible for Study
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Minimum Age: 55 Years
Maximum Age: 80 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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Nitrate rich beetroot juice<br>Subjects will consume 140 ml of beetroot juice (Beet-It Organic Shot) approximately 90 min before physiological testing. | Drug: Beetroot juice<br>* This beverage contains 0.3 g of inorganic nitrate per 70 ml container, and is bottled and supplied by James White Drinks (UK).<br>* Other names: Beet-It Organic Shot;|
| Placebo Comparator: Nitrate depleted beetroot juice<br>Subjects will consume 140 ml of beetroot juice (Beet-It Organic Placebo) approximately 90 min before physiological testing. | Drug: Beetroot juice placebo<br>* This beverage is identical in look and taste to the Beet-It organic shot, but has the nitrate removed. It is also bottled and supplied by James White Drinks (UK).<br>* Other names: Beet-It Organic placebo;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Resting Aortic Blood Pressures | Aortic Blood pressures were measured in the arm (cuff) and estimated in the aorta (radial artery tonometry). | Resting systolic blood pressure at 90 minutes after beetroot juice ingestion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood Measures of Nitrate Absorption and Conversion | Venous blood will be withdrawn (venipuncture) for determination of plasma nitrate and nitrite. | Change from baseline measures of plasma nitrate and nitrite at 90 minutes and at approximately 6 hours | 
| Resting Arterial Stiffness/Wave Properties | Carotid to femoral artery pulse wave velocity will be assessed using arterial tonometry. | Change from baseline resting pulse wave velocity at 90 minutes after beet root juice ingestion | 
| Handgrip Exercise Blood Pressure Responses (Relative Change From Baseline) | Beat-to-beat blood pressure (finger cuff) will be assessed at rest and during handgrip exercise to volitional fatigue. | Approximately 180 minutes after ingestion of beetroot juice | 
| Peak Rate of Perceived Exertion Scores During Handgrip Exercise | The Borg Rating of Perceived Exertion Scale (RPE) was used to assess exercise intensity during handgrip exercise. The RPE scale ranges from a minimum of 6 (no exertion at all) to a maximum of 20 (maximal exertion) units on a scale. | Approximately 90 minutes after ingestion of beetroot juice | 
| Handgrip Exercise Tolerance | Time to fatigue (seconds) was assessed during a progressive blood flow restricted handgrip exercise protocol. | Approximately 90 minutes after ingestion of beetroot juice | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dietary nitrate supplementation, Beetroot juice