This study will test whether potassium supplementation can reduce the deleterious effect of a high sodium diet on blood vessel function, blood pressure reactivity and autonomic nervous system function in apparently healthy adults.

Excess sodium intake is linked to poor blood pressure (BP) regulation and endothelial dysfunction, both of which are implicated in the pathogenesis of atherosclerosis and high BP. Evidence suggests potassium may offset the damaging effects of sodium; however, studies in healthy adults are lacking. This is important as these pre-clinical risk factors have been observed in this population, suggesting early intervention may be critical for cardiovascular disease prevention. High potassium diets have been effective at attenuating a sodium-induced decline in endothelial function. However, potassium intake was increased using whole foods; thus, the vascular benefits cannot be attributed solely to potassium. Furthermore, whether potassium can reduce sodium-induced oxidative stress is unknown. The central hypothesis of this study is that endothelial function will be greater and BP reactivity and oxidative stress will be lower with a high potassium intake compared to a low potassium intake, in the context of a high sodium diet. The investigators will assess macrovascular function using flow-mediated dilation, BP reactivity using the cold pressor test and isometric handgrip grip test, and oxidative stress using electron paramagnetic resonance.

Inclusion Criteria:

• men and women
• 18-45 years of age
• all races/ethnicities
• BMI < 30 kg/m2
• BP < 130/80 mmHg

Exclusion Criteria:

• presence of hypertension
• known heart disease
• diabetes
• kidney disease
• cancer
• inflammatory conditions
• blood clotting disorders
• pregnancy
• adrenal gland disorder
• history of stomach or intestinal bleeding
• history of kidney stones
• serum potassium outside of the normal range

Participants will be blinded to the diet they are on.