Salt Intake for High Blood Pressure Differences by Race

Recruiting at 1 trial location

Overseen By Austin Robinson, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Indiana University

Disqualifiers: Hypertension, Cardiovascular disease, Diabetes, Obesity, others

Compensation: Varies

Number of Visits: 3

100 Participants Needed

Trial Summary

What is the purpose of this trial?

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.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. However, it does mention that participants should not have any medical issues that prevent them from exercising or giving blood, which might imply some medication restrictions.

What data supports the effectiveness of the treatment Acute Salt (sodium chloride) for high blood pressure differences by race?

Research shows that high salt intake is linked to increased blood pressure and related health issues, suggesting that reducing salt intake can help manage blood pressure. This implies that understanding salt's role in blood pressure differences among races could be important for treatment. ^{1 2 3 4 5}

Is salt intake generally safe for humans?

High salt intake is linked to increased blood pressure and risks for heart and kidney diseases, but moderate reduction in salt intake is generally safe and can improve health. Some studies suggest that reducing salt too much might have negative effects, but moderate reduction is not associated with increased risk. ^{3 5 6 7 8}

How does the treatment of Acute Salt differ from other treatments for high blood pressure?

The treatment of Acute Salt (sodium chloride) is unique because it focuses on the role of salt intake in managing high blood pressure, unlike other treatments that may involve medications or lifestyle changes. This approach highlights the importance of reducing salt consumption to lower blood pressure and improve overall cardiovascular health. ^{1 3 5 9 10}

Research Team

Austin T Robinson, PhD

Principal Investigator

Auburn University

Eligibility Criteria

This trial is for non-smoking individuals aged 19-75 with a BMI below 35 and no history of metabolic, pulmonary, or cardiovascular diseases. Participants must have blood pressure under 150/90 mmHg and be free from conditions that limit exercise or blood donation.

Inclusion Criteria

I don't have health issues that stop me from exercising or giving blood.

My BMI is under 35.

I am between 19 and 75 years old.

Exclusion Criteria

I have had cancer in the past.

I have a history of heart disease.

Your blood pressure is lower than 90/50 mmHg.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline Assessment

Participants undergo baseline assessments including cardiorespiratory fitness, physical activity, habitual dietary intake, and mental health evaluations

1 week

1 visit (in-person)

Intervention

Participants consume a high-sodium meal and a low-sodium control meal, with assessments of blood pressure, vascular function, and blood samples before and after each meal

1 day per meal

2 visits (in-person)

Follow-up

Participants are monitored for changes in blood pressure regulation, blood vessel function, and biochemical markers after the intervention

4 weeks

Treatment Details

Interventions

• Acute Salt (sodium chloride)

Trial Overview The study investigates how dietary salt affects blood vessel function and blood pressure regulation differently in black versus white individuals. It also examines the impact of lifestyle factors like sleep, physical activity, and nutrition on these racial differences.

Participant Groups

Group I: High Sodium Meal (2500 mg sodium) Experimental Treatment 1 Intervention

Participants will have sympathetic nerve activity, vascular function, blood pressure and blood samples (from intravenous catheters) assessed before and after a high sodium meal (2500 mg sodium).

Group II: Low Sodium Meal (140 mg sodium) Placebo Group 1 Intervention

Participants will have sympathetic nerve activity, vascular function, blood pressure and blood samples (from intravenous catheters) assessed before and after a low sodium meal (140 mg sodium) which will serve as the control condition to demonstrate whether or not observed changes are due to high sodium or occur irrespective of sodium in the postprandial state.

Who Is Running the Clinical Trial?

Indiana University

Lead Sponsor

Trials

1,063

Recruited

1,182,000+

Auburn University

Lead Sponsor

Trials

81

Recruited

14,600+

University of Delaware

Collaborator

Trials

167

Recruited

25,700+

Findings from Research

Long-term high dietary salt intake is linked to increased blood pressure (BP) and a higher prevalence of hypertension, with evidence from both observational and randomized controlled studies.

Reducing salt intake in the population could lead to lower average BP levels and decrease the risk of cardiovascular complications associated with hypertension, potentially improving health outcomes as hypertension affects over 30% of adults and increases with age.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Reducing food salt content--a neglected approach to hypertension prevention and treatment in the population]. Horký, K.[2009]

In a study analyzing dietary intake and blood pressure of 1928 black and 9739 white adults, it was found that black individuals had a higher sodium/potassium ratio despite lower absolute sodium and potassium intakes compared to whites.

The research suggests that the higher blood pressure and prevalence of hypertension in black adults may be linked to their relatively low potassium intake rather than higher sodium intake, indicating a potential greater sensitivity to sodium's effects on blood pressure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Blood pressure in blacks and whites and its relationship to dietary sodium and potassium intake. Frisancho, AR., Leonard, WR., Bollettino, LA.[2022]

Global sodium intake levels are alarmingly high, with most adult populations consuming over 100 mmol/day, and many, especially in Asian countries, exceeding 200 mmol/day, which is well above the physiological need of 10-20 mmol/day.

The primary sources of dietary sodium differ by region, with manufactured foods contributing approximately 75% of sodium intake in Europe and North America, while home-added salt and soy sauce are major sources in Japan and China, highlighting the need for targeted public health policies to reduce sodium consumption.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Salt intakes around the world: implications for public health. Brown, IJ., Tzoulaki, I., Candeias, V., et al.[2023]

In a study comparing table salt sales in supermarkets across different racial communities in Houston, it was found that sales in predominantly black and Hispanic areas were 50-100% higher than in predominantly white areas, suggesting higher dietary sodium intake.

The findings raise questions about the potential link between increased table salt consumption and the higher prevalence of hypertension in black populations, but further research is needed to establish a causal relationship.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ethnic patterns of salt purchase in Houston, Texas. Kerr, GR., Amante, P., Decker, M., et al.[2022]

Excessive table salt intake is a significant factor in increasing blood pressure and is linked to various health issues, including arterial hypertension, coronary artery disease, and organ damage, as confirmed by numerous epidemiological and clinical studies.

Reducing salt intake can lead to lower blood pressure and decreased cardiovascular risks, and is beneficial for overall health, suggesting that public health initiatives should focus on promoting lower salt consumption alongside other lifestyle changes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Salt--hidden poison in everyday meal]. Jelaković, B., Premuzić, V., Skupnjak, B., et al.[2009]

Population studies indicate that high salt intake does not consistently correlate with negative health outcomes, despite common beliefs about its risks.

Extreme salt reduction may lower blood pressure in hypertensive individuals, but its effect is significantly less than that of antihypertensive medications, and other lifestyle changes like diet and weight loss are more effective and easier to implement.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Should dietary salt restriction be a basic component of antihypertensive therapy? Graudal, N., Galløe, A.[2019]

The study analyzed 180 canteen meals from 15 worksites and found that the average salt content was 3.8 g per meal for men and 2.8 g per meal for women, indicating a high intake that could contribute to elevated blood pressure.

Fast food samples showed even higher salt levels, averaging 13.8 g per 10 MJ, with some items like sausages containing up to 16.3 g per 10 MJ, highlighting the need for reduced salt content in both canteen and fast food meals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Salt content in canteen and fast food meals in Denmark. Rasmussen, LB., Lassen, AD., Hansen, K., et al.[2021]

High dietary salt intake is linked to increased risks of hypertension, cardiovascular diseases, and possibly obesity and stomach cancer, with current global intakes averaging 9-12 g per day, significantly above the WHO recommendation of less than 5 g per day.

Reducing salt intake to 5-6 g per day can lower blood pressure and morbidity rates, especially in salt-sensitive individuals, and should be accompanied by increased potassium intake from fruits and vegetables to further support blood pressure management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of Salt Intake on the Pathogenesis and Treatment of Hypertension. Rust, P., Ekmekcioglu, C.[2017]

Reducing dietary salt (NaCl) intake to a moderate level of 6 g/day is recommended for patients with hypertension or cardiovascular conditions, as it effectively lowers blood pressure.

However, there is insufficient evidence to suggest that reducing salt intake significantly impacts cardiovascular mortality, and for patients with fewer health issues, consuming up to 10 g/day of salt appears to be safe.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Salt restriction in people with hypertension and patients with cardiovascular disease : meaningfulness and extent]. Hoyer, J.[2018]

Recent research has strengthened the connection between high salt intake and high blood pressure, indicating that reducing salt consumption may help manage hypertension.

Additionally, there is growing evidence that salt can have harmful effects on health that are not related to blood pressure, suggesting that limiting salt intake could provide broader health benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary salt restriction: benefits for cardiovascular disease and beyond. Cappuccio, FP., MacGregor, GA.[2019]

References

1. Czech Republic pubmed.ncbi.nlm.nih.gov

[Reducing food salt content--a neglected approach to hypertension prevention and treatment in the population]. [2009]

2. England pubmed.ncbi.nlm.nih.gov

Blood pressure in blacks and whites and its relationship to dietary sodium and potassium intake. [2022]

3. England pubmed.ncbi.nlm.nih.gov

Salt intakes around the world: implications for public health. [2023]

4. United States pubmed.ncbi.nlm.nih.gov

Ethnic patterns of salt purchase in Houston, Texas. [2022]

5. Croatia pubmed.ncbi.nlm.nih.gov

[Salt--hidden poison in everyday meal]. [2009]

6. United States pubmed.ncbi.nlm.nih.gov

Should dietary salt restriction be a basic component of antihypertensive therapy? [2019]

7. Sweden pubmed.ncbi.nlm.nih.gov

Salt content in canteen and fast food meals in Denmark. [2021]

8. United States pubmed.ncbi.nlm.nih.gov

Impact of Salt Intake on the Pathogenesis and Treatment of Hypertension. [2017]

9. Germany pubmed.ncbi.nlm.nih.gov

[Salt restriction in people with hypertension and patients with cardiovascular disease : meaningfulness and extent]. [2018]

10. England pubmed.ncbi.nlm.nih.gov

Dietary salt restriction: benefits for cardiovascular disease and beyond. [2019]