The overall objective of this study is to examine how dietary sodium is used by the body. In a racially diverse sample of adults, the investigators will examine the effects of high and low dietary sodium intake on the storage and excretion of sodium and determine whether sodium distribution affects blood pressure. This has implications for how investigators interpret studies that use urine biomarkers of sodium. Study findings about tissue sodium storage also have implications for managing hypertension and related conditions.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
52
Fourteen day feeding period of high dietary sodium (3400 mg/day)
Fourteen day feeding period of low dietary sodium (2300 mg/day)
University of California, San Diego
San Diego, California, United States
Estimated sodium concentration in skin and muscle
The concentration of sodium in skin and muscle will be measured, and the difference in concentrations resulting from high versus low sodium intakes will be calculated. Skin and muscle sodium stores will be non-invasively quantified using 23sodium-magnetic resonance imaging (23Na-MRI).
Time frame: 60 days
Estimated sodium concentration in bone
The concentration of sodium in bone will be measured, and the difference in concentrations resulting from high versus low sodium intakes will be calculated. Sodium storage in bone will be measured non-invasively using in vivo neutron activation analysis (IVNAA) technology to quantify the concentration of Na in the hand.
Time frame: 60 days
Concentration of sodium, potassium, and hormone regulators in excreted urine
Urinary concentration of sodium, potassium, and hormones (renin, angiotensin, aldosterone, free cortisol, free cortisone, glucocorticoid, and mineralocorticoid) will be measured and variation over time will be calculated.
Time frame: 60 days
Blood pressure
Blood pressure under high versus low dietary sodium conditions will be measured.
Time frame: 60 days
Racial differences in concentrations of sodium in skin, muscle and bone
Blacks/African Americans mean sodium concentrations versus the average of the means of each of the other racial/ethnic groups will be examined.
Time frame: 60 days
Racial differences in concentration of urinary potassium excretion
The concentration of potassium excreted in urine will be compared between Blacks/African Americans versus the pooled sample of other racial/ethnic groups.
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Time frame: 60 days