An interventional study of Low Sodium Meal (140 mg sodium chloride) and High Sodium Meal (2500 mg sodium chloride) in Sodium Excess, Racial Disparities and Blood Pressure, sponsored by Indiana University. Completed at 2 sites in United States. Open to participants aged 19 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-19.
Sponsored by Indiana University · Not applicable, Interventional, and Prevention
This IRB will cover a current clinical trial (NCT04244604) that was started at Auburn University (AU IRB#19-390), the Principal Investigator's prior institution, and is supported by his NIH Career Development Award (NHLBI K01HL147998).
About nine out of ten Americans overconsume dietary salt. Compared to other racial groups, Black individuals are more prone to salt-sensitive hypertension and negative cardiovascular conditions associated with high salt intake. However, there is a critical need to determine the reasons behind and mechanisms that contribute to these racial disparities. Both acute (single meal) and chronic high-dietary sodium cause small but important increases in blood sodium concentration that are associated with altered blood pressure regulation and blood vessel dysfunction. However, racial differences in these measures have not been examined. This is important because Black individuals generally exhibit lower circulating concentrations of hormones (e.g., renin, aldosterone, angiotensin 2) that buffer changes in body sodium to regulate blood pressure, and this could make them more vulnerable to the negative effects of a high-sodium meal.
Therefore, the purpose of this study is to determine whether there are racial differences in blood pressure regulation and blood flow after a high-sodium meal. The investigators will assess blood pressure regulation, blood vessel stiffness, and the blood vessel's ability to dilate before and after a high-salt meal and a low-salt control meal (both meals are low-salt tomato soup with varied added salt). The investigators will also collect blood and urine to measure sodium and determine biochemical changes that may be contributing to racial differences in cardiovascular function.
The investigators have previously used a high-sodium saline infusion to increase blood sodium and consequently increase blood pressure in Black and White individuals. The investigators' prior data suggest that increased blood sodium concentrations result in larger blood pressure elevations for a given elevation in blood sodium levels in Black compared to White adults. In this proposal, the investigators are seeking to translate these previous findings using a single high-salt meal (up to 2500 mg of sodium; similar to a few slices of pizza or a sandwich/burger and side dish). Our primary aims are to determine if the high-sodium meal causes greater 1) blood pressure dysregulation 2) decreases in blood vessel function and 3) larger changes in blood sodium in Black compared to White individuals. Other potential questions that could be determined include aging differences or an influence of fitness. The investigators will not exclude other races/ethnicities as the project will also determine the response of other minority groups (e.g. Asian or Latine/Hispanic adults) to a high-salt meal.
Participants will report to the laboratory for four visits. At the first visit, consent for study participation will be obtained and participants will be screened for eligibility. Baseline assessments will be completed which may include fitness testing and body composition assessments. If necessary, these assessments may be completed at a second in-person visit. Participants will then report to the laboratory for two experimental visits. At each visit, participants will consume a randomly assigned meal (i.e., a soup containing either low- or high-salt) and undergo assessments prior to and 30- and 60-minutes after consumption. During the study, all participants will consume both meals, however, the order of exposure will be randomly assigned.
49 studies on the registry are indexed under Hypernatremia; 8 are open to participants now.
This study's enrollment of 71 is above the median of 64 across 32 interventional studies indexed under Hypernatremia.
Browse Hypernatremia studies →Indiana University is the lead sponsor of 986 studies on the registry; 198 are open to participants now.
Of its 148 completed or terminated interventional studies of FDA-regulated products, 118 (80%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
On experimental visit days, participants will consume each of the experimental meals, in this order. Prior to, and at several timepoints after consumption, they will have sympathetic nerve activity, vascular function, blood pressure and blood samples (from intravenous catheters) assessed.
Other: Low Sodium Meal (140 mg sodium chloride) · Other: High Sodium Meal (2500 mg sodium chloride)
On experimental visit days, participants will consume each of the experimental meals, in this order. Prior to, and at several timepoints after consumption, they will have sympathetic nerve activity, vascular function, blood pressure and blood samples (from intravenous catheters) assessed.
Other: Low Sodium Meal (140 mg sodium chloride) · Other: High Sodium Meal (2500 mg sodium chloride)
Varied amounts of salt (sodium chloride) will be added to a very low sodium soup to determine the effects of a single high sodium meal on measures of vascular function and autonomic regulation of blood pressure. The Low Sodium soup will serve as the control condition.
Varied amounts of salt (sodium chloride) will be added to a very low sodium soup to determine the effects of a single high sodium meal on measures of vascular function and autonomic regulation of blood pressure. The Low Sodium soup will serve as the control condition.
Changes in blood pressure reactivity
The investigators will measure systolic and diastolic pressure using photoplethysmography at the finger. Systolic and diastolic blood pressure will be assessed at rest and during handgrip exercise. Blood pressure reactivity will be expressed as a change in pressure (mmHg) from baseline to a predetermined time during the stressor (e.g., minute one average and minute two average).
Time frame: Before and one hour after soup, both conditions (high- and low- salt)
Changes in flow-mediated dilation (FMD)
Flow-mediated vasodilation will be assessed using continuous measures of brachial artery diameter and velocity via duplex Doppler ultrasound (Hitachi Arietta 70). The brachial artery will be imaged in the longitudinal plane proximal to the medial epicondyle using a high-frequency (6-12 MHz) linear-array probe. The ultrasound probe will be stabilized using a custom-built clamp. Shear rate (sec-1) will be calculated as \[(blood flow velocity (cm\*s-1) \*4)/blood vessel diameter (mm)\] The image will be recorded throughout a 60-s baseline, a 300-s ischemic stimulus (250 mmHg), and 180 seconds post deflation. FMD will be expressed as % dilation (final diameter-baseline diameter/baseline diameter x 100) and also normalized to the shear stimulus. Allometric scaling will be used if appropriate, including if there are baseline differences in artery diameter by race or condition.
Time frame: Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt)
Changes in indices of arterial stiffness
The investigators will use the SphygmoCor XCEL system to assess pulse wave analysis (PWA) and pulse wave velocity (PWV). A high-fidelity strain-gauge transducer is used to obtain the pressure waveform at the carotid and radial pulse. Distances from the carotid artery sampling site to the femoral artery (upper leg instrumented with a thigh cuff for oscillometric sphygmomanometry), and from the carotid artery to the suprasternal notch will be recorded. The investigators will also assess forward and reflective wave magnitudes. PWV will be expressed as cm/s and PWA will be expressed as % (calculated as augmentation pressure divided by the pulse pressure).
Time frame: Before 30 minutes, and one hour after soup, both conditions (high- and low- salt)
Changes in blood biomarkers of nitric oxide bioavailability
The investigators will measure nitric oxide metabolites (nitrate and nitrite nanomolar concentration).
Time frame: Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt)
Changes in circulating reactive oxygen species
The investigators will use electron paramagnetic resonance to measure reactive oxygen species (spectra units) in whole blood samples treated with a spin probe.
Time frame: Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt)
Changes in plasma sodium
The investigators will measure plasma sodium levels.
Time frame: Before, 30 minutes, and one hour after soup, both conditions (high- and low- salt)
Plan to share: Yes — Data with all HIPAA identifiers removed may be shared in future collaborative efforts pending appropriate DMDA approvals
Supporting information: Statistical analysis plan, Informed consent form, Analytic code
Time frame: One year after completion of trial, indefinitely
Access criteria: A formal plan identifying the intended use fo the data and proper completion of a DMDA and MTA (if needed) with Auburn University and the study PI.
Ran from May 2021 to primary completion in Dec 2025, 55 months.
Of 12 interventional studies with no phase under Hypernatremia, half reached primary completion within 10 months of starting (the median), counting those still running; a quarter within 3 and three quarters within 15. This study's 55 months is above that.
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This study is completed, as verified in Dec 2025. You cannot join it, but the record below documents what was studied.
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