Exploring the Effect of Inorganic Nitrates on the Human Microvascular Physiology - a Pilot Study.

NCT04276766 | Completed

• 1 other identifier: HWB-S&E-23
• Study Type: interventional
• Target: 25
• Locations: 0 countries
• Sites: N/A

Brief Summary

We conducted a randomised, placebo-controlled, double blind, cross-over, trial to examine the short-term effect of concentrated beetroot juice on vascular outcomes in a young (18-35 years) and older group (55-75 years). The study included a run-in period of one day preceding the test day. A wash-out period of at least 7 days was implemented to ensure to avoid a carry-over effect of the interventions.

Conditions

Aging

Keywords

nitrates; beetroot; nutrition; microcirculation; nitrites

Outcome Measures

Primary Outcomes (1)

• Change of micro-circulatory function from baseline

  Non-invasive laser Doppler flowmetry (LDF) measurements (Periflux 5000 System, Perimed, Sweden) will be used as an index of cutaneous (microcirculatory) function and red blood cell flux. To obtain a measure of microcirculatory, NO-dependent, endothelial-function (26) measurements will be taken once at Visit 1 and twice (prior to and 3 hrs. after beverage ingestion) on Visits 2 and 3, using thermal hyperaemia. For this, four 7-point integrating probes (Model 413, Perimed) housed within local heating units (Model 455, Perimed) will be placed on the ventral aspect of the left forearm. The heating units will be initially set at 33 °C. After a 10-min baseline recording, the temperature of the heating unit will then be increased to 42 °C at a rate of 1 °C every 10 seconds to obtain maximum skin blood flow; this (i.e., a stable plateau in skin blood flow) is usually observed after approx. 25 minutes of localised heating.

  3 hours

Secondary Outcomes (4)

• Blood pressure measurements

  Up to 24 hours

• Oral nitrate reductase capacity

  Up to 24 hours

• Whole-body NO production

  Up to 24 hours

• Urine / saliva sampling

  Up to 24 hours

Study Arms (2)

Beetroot

EXPERIMENTAL

Following baseline microcirculatory and blood pressure measurements, as well as the collection of urine and saliva samples, participants on the "beetroot" group were asked to consume 140ml beetroot juice (James White Drinks Company, Suffolk, UK). The 140 ml of beetroot juice equate to approximately 8.4 mmol of NO3- .

Other: Crossover intervention

Placebo

PLACEBO COMPARATOR

Following baseline microcirculatory and blood pressure measurements, as well as the collection of urine and saliva samples, participants on the "placebo" group were asked to consume 140 ml nitrate-depleted beetroot juice (James White Drinks Company, Suffolk, UK).

Other: Crossover intervention

Interventions

Crossover intervention OTHER

Drink consumption was followed by regular BP measurements and collection of saliva samples every 30 minutes for four hours. Microcirculatory measurements were then repeated and saliva and urine samples were collected again. After the last measurement subjects were provided with a standardized meal with a very low nitrate intake to eat within 30minutes. Participant then left the research centre and they were asked to collect a saliva sample after two hours from the completion of the meal. This was immediately followed a dose of labelled nitrate (4mg in 100ml of distilled water) to drink within one minute. Subjects were then asked to collect six additional saliva samples until the next morning (four before going to bed and two in the morning), accompanied by measurements of resting BP. Cross-over assessments were then repeated in the same order at Visit 3, followed a wash-out period of at least one week before entering the second arm of the study.

Beetroot; Placebo

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• non-smoking,
• healthy (defined by the absence of overt chronic diseases that could affect their micro- and macro- vascular function - e.g. chronic venous insufficiency, systemic sclerosis, hypercholesterolemia, diabetes, cardiovascular disease - as determined by a medical history questionnaire),
• male or female adults aged between 18 and 35 years (Group A) and 55 and 75 years (Group B).
• normotensive (systolic blood pressure (SBP) between 115 and 140 mmHg and diastolic blood pressure (DBP) between 75 and 90 mmHg) with body mass index (BMI) 18-30 kg/m2.

You may not qualify if:

• taking medications interfering with the study outcomes,
• have lost more than 3kg in the month before the study,
• wearing complete dentures and diagnosis of inflammatory oral diseases.

Sponsors & Collaborators

• Sheffield Hallam University: lead
• University of Sheffield: collaborator
• University of Nottingham: collaborator

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 13, 2020
• First Posted: February 19, 2020
• Study Start: June 1, 2015
• Primary Completion: December 1, 2016
• Study Completion: January 1, 2018
• Last Updated: February 19, 2020

Record last verified: 2020-02

Data Sharing

• IPD Sharing: Will not share