Efficacy of Dietary Sodium Restriction of Improving Vascular Endothelial Function in Middle Aged and Older Adults

NCT ID: NCT01566084

Last Updated: 2016-01-07

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 17 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2009-02-28
• Study Completion Date: 2012-01-31

Brief Summary

The investigators hypothesize that reducing salt in the diet will improve the function of blood vessels in middle aged and older adults with moderately elevated systolic blood pressure, by increasing the amount of BH4 and nitric oxide in your blood vessels and reducing the amount of oxidative stress.

Detailed Description

The improvement in blood vessel function will be determined over a 10 week period. Subjects will be randomly assigned to either a 'low salt' condition (placebo pills + 1200 mg dietary sodium) or a 'normal salt' condition (2300 mg sodium chloride pills + 1200 mg dietary sodium) and monitored for 5 weeks. After the initial set of 5 weeks, the subjects are switched into the opposite condition, completing the cross-over study design. During weeks 1-4 and 6-9, subjects are monitored weekly with 24 hour urine collections and diet logs. The assessment of the primary outcome (blood vessel function) is completed during weeks 5 and 10. BH4 and ascorbic acid are also administered during weeks 5 and 10 to measure the effects of sodium intake on endogenous BH4 levels and vascular oxidative stress.

Conditions

Hypertension

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Normal sodium

Subjects on a 1200 mg sodium diet are given 2300 mg sodium in the form of slow sodium tablets to bring them back up to a normal salt intake. Subjects then cross-over to the low sodium condition in the second half of the study.

Group Type: OTHER

Slow sodium tablets

Intervention Type: DRUG

The normal salt condition is maintained with 2300 mg / day in the form of slowly released salt (NaCl) tablets.

Low sodium

Subjects on a 1200 mg salt diet are given placebo pills in order to maintain them on a low salt diet. Subjects then cross-over to the normal sodium condition in the second half of the study.

Group Type: OTHER

placebo

Intervention Type: OTHER

Placebo tablets are administered to maintain the low sodium condition.

Interventions

Slow sodium tablets

The normal salt condition is maintained with 2300 mg / day in the form of slowly released salt (NaCl) tablets.

Intervention Type: DRUG

placebo

Placebo tablets are administered to maintain the low sodium condition.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• 50-79 years of age
• SBP 130-159 mmHg

Exclusion Criteria

• Have been sick with an infection in the past two weeks
• Are currently sick or have ongoing health problems such as kidney or CVD
• Have lost more than 11 lbs. in the last 3 months
• Are taking any type of antioxidants
• Smoke or have alcohol problems
• Have blood glucose levels higher than 126 mg/dL
• Have resting SBP below or less than 100 mmHg or greater than 159 mmHg
• Have a resting diastolic blood pressure greater than 99 mmHg
• Have a BMI greater than 40 kg/m^2
• Are presently consuming less than 9 or greater than 18 grams of salt / day
• Have a baseline FMD of greater than 6%
• Are taking any of the following types of drugs: blood thinners, anti-seizure medications, ant-inflammatory drugs
• Participate in any high endurance athletic training
• Taking Hormone Replacement Therapy
• Have not been post-menopausal for at least 1 year

• Minimum Eligible Age: 50 Years
• Maximum Eligible Age: 79 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute on Aging (NIA)

NIH

Sponsor Role: collaborator

University of Colorado, Boulder

OTHER

Sponsor Role: lead

Responsible Party

Douglas Seals

College Professor of Distinction

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Kristen L Jablonski, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Colorado, Boulder

Locations

Clinical Translational Research Center

Boulder, Colorado, United States

Countries

United States

Related Links

http://www.colorado.edu/intphys/research/cardiovascular.html

Integrative Physiology of Aging Laboratory Website

Other Identifiers

F31AG033994

Identifier Type: NIH

Identifier Source: secondary_id

View Link

B5114

Identifier Type: -

Identifier Source: org_study_id