Clinical trial NCT01566084: Efficacy of Dietary Sodium Restriction of Improving Vascular Endothelial Function in Middle Aged and Older Adults
Official title: Efficacy of Dietary Sodium Restriction of Improving Vascular Endothelial Function in Middle Aged and Older Adults
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hypertension
Lead sponsor: University of Colorado, Boulder
Sponsor class: OTHER
Collaborators: name: National Institute on Aging (NIA)
First posted: 2012-03-29
Enrollment: 17
Sex: ALL
Minimum age (years): 50
Maximum age (years): 79
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

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.

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

Primary outcomes:
measure: Improved Flow Mediated Dilation
timeFrame: Week 5 (after first condition of low salt or normal salt), Week 10 (after second condition, opposite to first)
Secondary outcomes:
measure: Vascular Oxidative Stress
timeFrame: Immediately following acute infusion of ascorbic acid on Weeks 5 and 10
measure: BH4 Bioavailability
timeFrame: Immediately following acute administration of BH4 on Weeks 5 and 10
Other outcomes:
Locations:
city: Boulder
country: United States
facility: Clinical Translational Research Center
state: Colorado
Study officials:
affiliation: University of Colorado, Boulder
name: Kristen L Jablonski, PhD
role: PRINCIPAL_INVESTIGATOR
References: