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

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)