Adverse Neurogenic Actions of Dietary Salt

March 22, 2023 updated by: William Farquhar, University of Delaware
Excess dietary salt increases the risk for cardiovascular events, even in people that are not hypertensive. There is some evidence that excess dietary salt exaggerates blood pressure and sympathetic nervous system responses to various perturbations and increases blood pressure variability. This proposal will examine the effects of low, medium, and high salt diets on cardiovascular reactivity and blood pressure variability.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Excess dietary salt causes target organ damage and increases the risk for adverse cardiovascular (CV) events independent of blood pressure (BP). Recent data in salt-resistant, normotensive rodents suggest that high dietary salt enhances the excitability or gain of sympathetic circuits, exaggerates sympathetic and CV responses to various stimuli, and increases BP variability (BPV). There are limited data regarding the impact of dietary salt intake on sympathetic nerve activity (SNA) and CV function in salt-resistant humans as well as the underlying mechanisms contributing to these adverse effects. The long-term goal is to determine how dietary salt adversely affects BP regulation and CV health. The objective of this proposal is to comprehensively evaluate the impact of dietary salt intake on SNA and CV reactivity and BPV in normotensive humans. The investigators have 2 specific aims: 1) Aim 1 will test the hypothesis that high dietary salt increases SNA and CV reactivity in normotensive adults, 2) Aim 2 will test the hypothesis that high dietary salt increases BPV in normotensive adults. The expected outcome is to demonstrate that dietary salt loading increases CV reactivity and BPV through a sympathetic nervous system mechanism that originates in the brain. The proposed research is significant, as these studies will provide empirical evidence that dietary salt intake impacts neurohumoral control of the circulation in salt-resistant humans. The proposed research is innovative because it will identify a novel neurogenic action of dietary salt in human CV regulation.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
77

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: William B Farquhar, PhD
  • Phone Number: 302-831-6178
  • Email: wbf@udel.edu

Study Contact Backup

Study Locations

  • United States
    • Delaware
      • Newark, Delaware, United States, 19716
        • University of Delaware

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

21 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • normal blood pressure
  • men, Women, minorities
  • ECG within normal limits
  • screening blood panel within normal limits

Exclusion Criteria:

  • high blood pressure (>140/90 mmHg)
  • history of cardiovascular disease
  • history of cancer
  • history of diabetes
  • history of kidney disease
  • obesity (BMI > 30 kg/m2)
  • smoking or tobacco use
  • current pregnancy
  • nursing mothers
  • communication barriers

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Blood Pressure Reactivity
Blood Pressure Responses to a cold pressor test and acute exercise will be assessed. This will be performed while subjects are on a low sodium diet (1000 mg/daily), medium sodium diet (2300 mg/daily), and high sodium diet (7000 mg/daily).
Other: Low Sodium Diet
Ten days of low sodium diet
Other: Medium Sodium Diet
Ten days of a medium sodium diet
Other: High Sodium Diet
Ten days of a high sodium diet
Experimental: Blood Pressure Variability
Twenty four hour blood pressure variability will be assessed. This will be performed while subjects are on a low sodium diet (1000 mg/daily), medium sodium diet (2300 mg/daily), and high sodium diet (7000 mg/daily).
Other: Low Sodium Diet
Ten days of low sodium diet
Other: Medium Sodium Diet
Ten days of a medium sodium diet
Other: High Sodium Diet
Ten days of a high sodium diet

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Blood Pressure Variability
Time Frame: Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Standard deviation of systolic blood pressure over 24 hours (mmHg)
Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Blood Pressure Reactivity - Handgrip exercise
Time Frame: Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Change in Blood pressure during handgrip exercise (mmHg)
Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Blood Pressure Reactivity - Cold Pressor test
Time Frame: Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Change in Blood pressure during a cold pressor test (mmHg)
Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Sympathetic Responses - Handgrip exercise
Time Frame: Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Sympathetic outflow (bursts per minute)
Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Sympathetic Responses - Cold Pressor test
Time Frame: Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)
Sympathetic outflow (bursts per minute)
Day 10 of diet (i.e., after 10 days of low, medium, and high sodium diets; crossover design)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Delaware

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: William B Farquhar, PhD, University of Delaware

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 1, 2016

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 22, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 22, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 15, 2016

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 23, 2016

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 29, 2016

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 23, 2023

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 22, 2023

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2023

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 819183

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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