Interactive Effects of Sodium and Potassium on Vascular Health in Older Adults

Exploring the Interactive Effects of Sodium and Potassium Intake on Vascular Health in Older Adults

The goal of this clinical trial is to determine if a high potassium intake can counteract the harmful effects of excess sodium on endothelial function in older adults with no history of cardiometabolic disease. The main questions it aims to answer are:

1. Can a high potassium intake attenuate dietary sodium-induced endothelial dysfunction in older adults.
2. Do changes in endothelial function in response to alterations in sodium and potassium intake differ by sex.

Participants will participants will consume three controlled diets for 10 days each with a minimum 14-day washout between interventions. The order in which participants consume the diets will be randomized. The study diets will vary in sodium and potassium content. Measures of cardiovascular health (blood pressure, arterial stiffness, endothelial function) will be assessed at the end of each diet.

Study Overview

• Status: Recruiting
• Conditions: Healthy Older Adults
• Intervention / Treatment: Other: low sodium/low potassium diet; Other: high sodium/low potassium diet; Other: high sodium/high potassium diet

Detailed Description

Cardiovascular health declines with age, especially in postmenopausal females. High sodium diets are a major contributor to cardiovascular disease. Unfortunately, reducing sodium intake can be challenging. It is known that increasing potassium intake can improve cardiovascular disease risk factors in young adults, even if sodium intake remains high. The investigators are hoping to show that potassium can improve cardiovascular health in the context of a high sodium diets in older adults. In this study, participants will consume three 10-day controlled diets in a randomized order. The study diets will include: 1) a low sodium (2,000 mg/day)/low potassium (2,000 mg/day) diet; 2) a high sodium (4,700 mg/day)/usual potassium diet; and 3) a high sodium/high potassium (4,700 mg/day). All food will be provided to participants during these periods, and participants will be instructed not to consume any outside food or beverages. Dietary interventions will be separated by a minimum two-week washout period. Measurements of cardiovascular health will be collected at the end of each diet.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: FSU Ann's College; Phone Number: 850-644-6685
• Study Contact Backup: Name: Andrea Lobene; Phone Number: 850-644-1829; Email: alobene@fsu.edu

Study Locations

• United States
  • Florida
    • Tallahassee, Florida, United States, 32306
      • Recruiting
      • Florida State University
      • Contact: Andrea Lobene; Phone Number: 850-644-1829; Email: alobene@fsu.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults ages 55-75 years
• At least one-year post-menopause (females)
• Willing and able to attend laboratory visits

Exclusion Criteria:

• BMI ≥35 kg/m2
• Seated blood pressure >135/85 mmHg
• Current diagnosis or history of cardiovascular disease, diabetes, renal disease, cancer, or major cardiovascular event (e.g. heart attack or stroke)
• Taking exogenous hormones or hormone replacement therapy
• Following a vegan or gluten free diet
• Significant weight loss (>10% of body weight) in the last 6 months, or actively trying to lose weight
• Current or recent use of a diuretic (within the past 6 months) (e.g. spironolactone, eplerenone)
• Current or recent use of a potassium binding medication (within the past 6 months)
• Current use of blood pressure lowering medications (e.g. ACE inhibitors, calcium channel blockers, diuretics, vasodilators, beta blockers, AngII receptor blockers)
• Current or recent use of the medication trimethoprim
• Elevated blood lipids (LDL cholesterol ≥190 mg/dL)
• Elevated serum potassium level (>5.1 mmol/L)
• Elevated BUN (>22 mg/dL)
• Elevated creatinine (>1.2 mg/dL)
• Low eGFR (<90 mL/min/1.73 m²)
• Current or recent use of tobacco, nicotine, or illicit drugs
• Radical hysterectomy or oophorectomy (females)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: low Na/low K, high Na/low K, high Na/high K; Three 10-day controlled diets in randomized order, each varying in sodium and potassium content. There is a minimum 2-week washout between diets.	Other: low sodium/low potassium diet; On this intervention, participants will be given a diet that provides 2,000 mg Na/day and 2,000 mg K/day; Other: high sodium/low potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 2,000 mg K/day; Other: high sodium/high potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 4,700 mg K/day
Experimental: low Na/low K, high Na/high K, high Na/low K; Three 10-day controlled diets in randomized order, each varying in sodium and potassium content. There is a minimum 2-week washout between diets.	Other: low sodium/low potassium diet; On this intervention, participants will be given a diet that provides 2,000 mg Na/day and 2,000 mg K/day; Other: high sodium/low potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 2,000 mg K/day; Other: high sodium/high potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 4,700 mg K/day
Experimental: high Na/high K, low Na/low K, high Na/low K; Three 10-day controlled diets in randomized order, each varying in sodium and potassium content. There is a minimum 2-week washout between diets.	Other: low sodium/low potassium diet; On this intervention, participants will be given a diet that provides 2,000 mg Na/day and 2,000 mg K/day; Other: high sodium/low potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 2,000 mg K/day; Other: high sodium/high potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 4,700 mg K/day
Experimental: high Na/high K, high Na/low K, low Na/low K; Three 10-day controlled diets in randomized order, each varying in sodium and potassium content. There is a minimum 2-week washout between diets.	Other: low sodium/low potassium diet; On this intervention, participants will be given a diet that provides 2,000 mg Na/day and 2,000 mg K/day; Other: high sodium/low potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 2,000 mg K/day; Other: high sodium/high potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 4,700 mg K/day
Experimental: high Na/low K, low Na/low K, high Na/high K; Three 10-day controlled diets in randomized order, each varying in sodium and potassium content. There is a minimum 2-week washout between diets.	Other: low sodium/low potassium diet; On this intervention, participants will be given a diet that provides 2,000 mg Na/day and 2,000 mg K/day; Other: high sodium/low potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 2,000 mg K/day; Other: high sodium/high potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 4,700 mg K/day
Experimental: high Na/low K, high Na/high K, low Na/low K; Three 10-day controlled diets in randomized order, each varying in sodium and potassium content. There is a minimum 2-week washout between diets.	Other: low sodium/low potassium diet; On this intervention, participants will be given a diet that provides 2,000 mg Na/day and 2,000 mg K/day; Other: high sodium/low potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 2,000 mg K/day; Other: high sodium/high potassium diet; On this intervention, participants will be given a diet that provides 4,700 mg Na/day and 4,700 mg K/day

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Endothelial function	Brachial artery flow-mediated dilation as measured in % dilation	"Day 11" after each of the three 10-day dietary interventions
Blood pressure	24-hour ambulatory blood pressure	"Day 11" after each of the three 10-day dietary interventions
Arterial stiffness	Carotid-femoral pulse wave velocity	"Day 11" after each of the three 10-day dietary interventions

Collaborators and Investigators

• Sponsor: Florida State University
• Collaborators: University of Florida
• Investigators: Principal Investigator: Andrea Lobene, Florida State University

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: June 9, 2026
• First Submitted That Met QC Criteria: June 11, 2026
• First Posted (Actual): June 15, 2026

Study Record Updates

• Last Update Posted (Actual): June 15, 2026
• Last Update Submitted That Met QC Criteria: June 11, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: potassium; endothelial function; sodium; cardiovascular disease risk factors
• Other Study ID Numbers: STUDY00006676; UF-FSU CTSA Career Development (Other Grant/Funding Number: UF-FSU Clinical and Translational Science Award)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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