Vascular Effects of Dietary Potassium

Vascular Effects of Dietary Potassium in Humans

The purpose of this study is to determine if dietary potassium can attenuate the deleterious effects of high sodium on blood vessel function in healthy, salt-resistant participants.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Risk Factor
• Intervention / Treatment: Other: Moderate Potassium/Low Sodium Diet; Other: Moderate Potassium/High Sodium Diet; Other: High Potassium/High Sodium Diet

Detailed Description

Cardiovascular disease remains a major Public Health problem in the U.S. and is the result of diseases such as atherosclerosis and high blood pressure (BP). Several dietary factors have been implicated as risk factors including high sodium and low potassium diets. Indeed, it is well known that excess sodium can increase BP while potassium rich diets have BP lowering properties. While the role of these two nutrients on BP is widely accepted, their impact on the vasculature has received less attention. Endothelial dysfunction, characterized by impaired dilation is an important non-traditional risk factor for atherosclerosis. Data in animal models suggest that salt loading, independent of changes in BP, results in endothelial dysfunction while evidence is mounting that potassium may be beneficial to vascular health. Further, potassium may be more effective in the presence of high sodium however the role of potassium in protecting the vasculature from a high sodium diet in salt-resistant adults has not been explored. A potential mechanism responsible for sodium induced vascular dysfunction is overproduction of reactive oxygen species resulting in reduced nitric oxide (NO) production/ bioavailability. It has been suggested that potassium can counteract sodium's effect by reducing ROS. The central hypothesis is that potassium can protect against the deleterious effects of high sodium on the vasculature by reducing oxidative stress and preserving NO. In this grant, the investigators propose to use a 21-day controlled feeding study to compare the effects of a high sodium diet (300 mmol) combined with either a high (120 mmol) or moderate (65 mmol) amount of potassium and low sodium (50 mmol) combined with moderate potassium (crossover design, diet order sequence randomized) on 2 levels of the vasculature, conduit artery and microvasculature. These experiments will be performed in salt-resistant participants to study the vascular effects alone, independent of changes in BP.

• Study Type: Interventional
• Enrollment (Actual): 47
• Phase: Not Applicable

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 22 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• healthy
• normal blood pressure

Exclusion Criteria:

• hypertension
• history of heart disease
• diabetes
• kidney disease
• obese (BMI ≥30)
• significant weight changes in the last 6 months
• use of tobacco products
• pregnant
• on a special diet (gluten free; vegan)
• take any medications for the above conditions
• endurance trained athletes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Moderate Potassium/Low Sodium Diet; Vascular function will be assessed at both the conduit artery and microvascular level after 7 days of the moderate potassium/low sodium diet.	Other: Moderate Potassium/Low Sodium Diet; 7 days of the prescribed diet
Other: Moderate Potassium/High Sodium Diet; Vascular function will be assessed at both the conduit artery and microvascular level after 7 days of the moderate potassium/high sodium diet.	Other: Moderate Potassium/High Sodium Diet; 7 days of the prescribed diet
Other: High Potassium/High Sodium Diet; Vascular function will be assessed at both the conduit artery and microvascular level after 7 days of the high potassium/high sodium diet.	Other: High Potassium/High Sodium Diet; 7 days of the prescribed diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Conduit artery endothelial-dependent dilation	The change in flow-mediated dilation (FMD) between the 3 diets as assessed by brachial artery FMD	on the 7th day of each diet

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Arterial Stiffness	Assessed by carotid to femoral artery pulse wave velocity	on 7th day of each diet
Wave reflection	Assessed by augmentation index	on 7th day of each diet
Endothelial cell expression of oxidative stress marker	Assessed in venous endothelial cells from participants.	on the 7th day of each diet
Ambulatory blood pressure	Assessed by 24 hr ambulatory blood pressure monitoring.	7 days

Collaborators and Investigators

• Sponsor: University of Delaware

Study record dates

Study Major Dates

• Study Start (Actual): July 25, 2013
• Primary Completion (Actual): September 22, 2019
• Study Completion (Actual): September 22, 2019

Study Registration Dates

• First Submitted: August 25, 2017
• First Submitted That Met QC Criteria: August 25, 2017
• First Posted (Actual): August 29, 2017

Study Record Updates

• Last Update Posted (Actual): November 5, 2020
• Last Update Submitted That Met QC Criteria: November 4, 2020
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Keywords: Sodium; Potassium; Vascular function
• Other Study ID Numbers: 487998-8

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No