Effects of Nitrate in Vegetables on Blood Pressure in Subjects With Prehypertension

Not Applicable

Completed

• Conditions: Cardiovascular Disease; Hypertension
• Interventions: Other: High nitrate vegetables; Dietary Supplement: Low nitrate vegetables + nitrate; Other: Low nitrate vegetables

• Registration Number: NCT02916615
• Lead Sponsor: Karolinska Institutet

Brief Summary

The purpose of this study is to examine the effect of different vegetables on cardiovascular function in subjects with moderately increased blood pressure. Specifically we are comparing the effects of vegetables with a high natural content of inorganic nitrate with those of vegetables with a low nitrate content.

Detailed Description

Recent studies indicate that dietary-derived inorganic nitrate can affect blood pressure in humans by converting into nitric oxide bioactivity. Here we will study if vegetables that naturally contain high amounts of nitrate (green leafy vegetables) can lower blood pressure and whether any effect is attributed to the nitrate anion. High nitrate vegetables are compared with vegetables low in nitrate (e.g. tomatoes, sweet pepper). After a 2 week run in period where all subjects receive vegetables low in nitrate, the participants are randomized to one of three interventions. One third of the patients receive high-nitrate vegetables + a placebo pill (KCl), one third receives low-nitrate vegetables + placebo and the third group receives low-nitrate vegetables + a nitrate pill (KNO3). The nitrate content in the pill is precisely matched to the nitrate content in the high-nitrate vegetable group.

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study Start: 2016-01
• Study First Submitted: 2016-09-26
• Study First Submitted QC: 2016-09-26
• Study First Posted: 2016-09-27
• Primary Completion: 2019-01-30
• Study Completion: 2019-01-30
• Status Verified: 2019-03
• Last Update Submitted: 2019-03-21
• Last Update Posted: 2019-03-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 225

Inclusion Criteria

Age 50-70 years Systolic blood pressure >130 at screening visit 2

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Exclusion Criteria

Systolic blood pressure <120 or >159 mm Hg at screening 2 Systolic blood pressure > 169 mm Hg at screening 1 Chronic kidney disease Chronic rheumatic disease Insulin treated diabetes mellitus Atrial fibrillation Major cardiovascular event within 6 months Inflammatory bowel disease Malignancy, actively treated within 6 months Hepatitis Polycytemia Vera

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
High nitrate vegetables	High nitrate vegetables	During 5 weeks subjects receive 100-150 g of a leafy green vegetable (High nitrate vegetables) per day and placebo pills containing 300 mg KCl (2 x 150 mg).
Low nitrate vegetables + nitrate	Low nitrate vegetables + nitrate	During 5 weeks subjects receive 100-150 g of tomatoes/sweet pepper (Low nitrate vegetables) per day and nitrate pills containing 300 mg KNO3 (2 x 150 mg).
Low nitrate vegetables	Low nitrate vegetables	During 5 weeks subjects receive 100-150 g of tomatoes/sweet pepper (Low nitrate vegetables) per day and placebo pills containing 300 mg KCl (2 x 150 mg).

Primary Outcome Measures

Name	Time	Method
Difference in Change in ambulatory Systolic Blood Pressure From Baseline	5 weeks intervention	Measure how 24h ambulatory SBP changes over 5 weeks with the different interventions

Secondary Outcome Measures

Name	Time	Method
Difference in Change in ambulatory diastolic Blood Pressure From Baseline	5 weeks intervention	Measure how 24h ambulatory DBP changes over 5 weeks with the different interventions
Difference in Change in office diastolic blood pressure (DBP)	Once every week for 5 weeks	BP is measured during a hospital visit every week during intervention
Difference in Change in flow mediated dilatation (FMD)	5 weeks intervention	FMD is measured before and after the interventions
Difference in Change in office Systolic Blood Pressure From Baseline	5 weeks intervention	Measure how clinic SBP changes weekly over 5 weeks with the different interventions
Difference in Change in Daytime Ambulatory systolic Blood Pressure From Baseline	5 weeks intervention	Measure how 24h ambulatory daytime SBP changes over 5 weeks with the different interventions

Trial Locations

Locations (1)

Karolinska Institutet; 🇸🇪 Stockholm, Sweden