This Study Will Look at How Elevated Na+ Alters the Gut Microbiota, Particularly in Salt-sensitive Individuals, and is Associated With Inflammation, Metabolic Changes, and SSBP. The Study Will Examine 50 Individuals Using Randomized Crossover Trial Design.

NCT07790900 | Not Yet Recruiting

• 2 other identifiers: 2517511R01HL182899-01
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this interventional study is to learn if elevated Na+ alters the gut microbiota and is associated with altered metabolism, inflammation and salt sensitivity of blood pressure (SSBP). The main questions it aims to answer are:

• SSBP correlates with Na+-induced changes in gut microbiome composition
• Na+-induced changes in the gut microbiome and SSBP are associated with altered metabolism and with immune cell activation
• Microbiota from humans with SSBP induce inflammation and hypertension in germ-free mice. Researchers will quantify SSBP from 24-hour ambulatory BP monitoring in a randomized crossover design, using standardized one week low- and high-salt diets. Participants will:
• Take high- and low-salt diet each for one-week
• Complete three study visits, with each visit being 1 week apart
• Complete a 72-hour dietary log

Conditions

Salt-sensitivity of Blood Pressure

Outcome Measures

Primary Outcomes (1)

• Salt sensitivity of blood pressure

  Mean arterial pressure from 24 hour ambulatory pressure monitoring, calculated as MAP (high-salt) - MAP (low-salt)

  2 weeks

Secondary Outcomes (3)

• Prevotella

  2 weeks

• Firmicutes

  2 weeks

• Tumor necrosis factor alpha (TNF alpha)

  2 weeks

Study Arms (2)

High-salt then low-salt diet

OTHER

Participants will undergo high- then low-salt diet week

Other: Dietary sodium

Low-salt then high-salt diet

OTHER

Participants will undergo a low- then high-salt diet week.

Other: Dietary sodium

Interventions

Dietary sodium OTHER

To quantify salt sensitivity of blood pressure, each participant will consume a high-salt diet and a low-salt diet, with each diet lasting one week.

High-salt then low-salt diet; Low-salt then high-salt diet

Eligibility Criteria

• Age: 50 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 50 years and ≤ 70 years.
• Omnivore.
• Willing to adhere to the study protocol.
• Able to provide written consent.

You may not qualify if:

• Unwilling to make dietary changes or otherwise adhere to the study protocol.
• Contraindications to high- or low-salt diet (e.g. heart, renal, or liver failure, postural orthostatic tachycardia syndrome)
• Use of salt tabs, fludricortisone, or midodrine.
• Contraindications to 24-hour ambulatory blood pressure monitoring, e.g. bilateral upper extremity lymphedema.
• Medical contraindications to foods, e.g. celiac disease, nut allergy, egg allergy, etc.
• Systolic blood pressure \< 90 or \> 160 mm Hg or diastolic blood pressure \< 50 or \> 100 mm Hg at screening
• Current use of anti-hypertensive medications
• Current use of oral steroids, daily NSAIDS, anti-inflammatory or immune modulating medications, probiotics, or antibiotics.
• Rheumatologic condition (e.g. Lupus, Rheumatoid Arthritis, Psoriatic arthritis, Inflammatory Bowel Disease, Multiple Sclerosis).
• Presence of acute or chronic medical conditions not generalizable to the general population (including eating disorders, cancer, severe mental illness, cognitive impairment, pregnancy or lactation).

Sponsors & Collaborators

• Vanderbilt University Medical Center: lead
• National Heart, Lung, and Blood Institute (NHLBI): collaborator

Study Sites (1)

Vanderbilt University Medical Center

Nashville, Tennessee, 37232, United States

Location

MeSH Terms

Interventions

Sodium, Dietary

Intervention Hierarchy (Ancestors)

Sodium Compounds; Inorganic Chemicals

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The study diets and diet orders are known to the participants and investigators. The outcomes assessors (blood pressure, gut microbiome, and inflammatory markers) will be masked to the study diets.
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor of Medicine

Study Record Dates

• First Submitted: August 24, 2026
• First Posted: August 27, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): March 1, 2031
• Study Completion (Estimated): September 1, 2031
• Last Updated: August 27, 2026

Record last verified: 2026-08

Locations

US (1)