Melatonin and Salt on Blood Vessel Function

Study Overview
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Brief Summary
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Increased dietary sodium causes increases in oxidative stress and damages blood vessels. Americans eat more than the recommended amount of sodium. Melatonin is a powerful endogenous antioxidant that has reduced oxidative stress levels in clinical and healthy populations. This study will investigate whether melatonin can attenuate the negative effects of sodium on blood vessels.

Detailed Description
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Americans consume on average double the recommended amount of sodium established by organizations such as the American Heart Association and the Dietary Guidelines for Americans. Excess dietary sodium damages the inside of our blood vessels in a process known as endothelial dysfunction. This reduces the ability of blood vessels to dilate as much. This type of dysfunction can lead to the development of cardiovascular disease. Animal and human studies have identified one potential mechanism linking high sodium consumption and endothelial dysfunction; that is oxidative stress. Furthermore, high dietary sodium consumption has been shown to increase blood pressure reactivity in animal studies. Melatonin is a powerful endogenous antioxidant that has reduced oxidative stress levels in clinical and healthy populations. Melatonin has been shown to attenuate sympathetic responses, but research is limited. Whether supplementation of melatonin can offset the deleterious effects of a high sodium diet is unknown. Thus, the purpose of this study is to investigate the effect of melatonin supplementation compared to a placebo on markers of oxidative stress and blood vessel function in healthy young adults that consume a 10-day high sodium diet. Our hypotheses are that: 1) melatonin will reduce oxidative stress levels and restore blood vessel function and 2) melatonin will reduce the sympathetic nerve response to high sodium consumption.

Official Title
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Melatonin and Salt on Blood Vessel Function

Conditions
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Cardiovascular Risk Factor

Intervention / Treatment
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* Dietary Supplement: Melatonin
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy normal blood pressure Exclusion Criteria: hypertension heart disease diabetes kidney disease renal impairment cancer obese (BMI ≥30) sleep disorder use of tobacco products pregnant or breastfeeding take any medications for the above conditions endurance trained athletes night shift worker melatonin or antioxidant consumption for the previous 3 months use of selective serotonin reuptake inhibitors

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: This is a randomized crossover design trial.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High Salt and Melatonin<br>Subjects will consume sodium pills throughout the day achieving a total of 6900 mg sodium/day (4600 mg of sodium from pills and 2300 mg from diet) and will supplement with 10 mg (single dose) of melatonin at night. | Dietary Supplement: Melatonin<br>* Daily consumption of a high sodium diet and melatonin for 10 days<br>|
| Placebo Comparator: High Salt and Placebo<br>Subjects will consume sodium pills throughout the day achieving a total of 6900 mg sodium/day (4600 mg of sodium from pills and 2300 mg from diet) and will supplement with a lactose placebo (single dose) at night. | Other: Placebo<br>* aily consumption of a high sodium diet and placebo for 10 days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Conduit artery endothelial-dependent function | Assessed by brachial artery flow mediated dilation (FMD) | Day 10 | 
| Microvascular function | Assessed by Near Infrared Spectroscopy (NIRS) | Day 10 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood pressure reactivity | Assessed by the change in blood pressure during Handgrip Exercise and Cold Pressor test from baseline | Day 10 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vascular Health, Melatonin, Dietary Sodium, Blood Pressure