Vascular Effects of Dietary Potassium

Cardiovascular disease remains a major Public Health problem in the U.S. and is the result of
diseases such as atherosclerosis and high blood pressure (BP). Several dietary factors have
been implicated as risk factors including high sodium and low potassium diets. Indeed, it is
well known that excess sodium can increase BP while potassium rich diets have BP lowering
properties. While the role of these two nutrients on BP is widely accepted, their impact on
the vasculature has received less attention. Endothelial dysfunction, characterized by
impaired dilation is an important non-traditional risk factor for atherosclerosis. Data in
animal models suggest that salt loading, independent of changes in BP, results in endothelial
dysfunction while evidence is mounting that potassium may be beneficial to vascular health.
Further, potassium may be more effective in the presence of high sodium however the role of
potassium in protecting the vasculature from a high sodium diet in salt-resistant adults has
not been explored. A potential mechanism responsible for sodium induced vascular dysfunction
is overproduction of reactive oxygen species resulting in reduced nitric oxide (NO)
production/ bioavailability. It has been suggested that potassium can counteract sodium's
effect by reducing ROS. The central hypothesis is that potassium can protect against the
deleterious effects of high sodium on the vasculature by reducing oxidative stress and
preserving NO. In this grant, the investigators propose to use a 21-day controlled feeding
study to compare the effects of a high sodium diet (300 mmol) combined with either a high
(120 mmol) or moderate (65 mmol) amount of potassium and low sodium (50 mmol) combined with
moderate potassium (crossover design, diet order sequence randomized) on 2 levels of the
vasculature, conduit artery and microvasculature. These experiments will be performed in
salt-resistant participants to study the vascular effects alone, independent of changes in
BP.

Inclusion Criteria:

- healthy

- normal blood pressure

Exclusion Criteria:

- hypertension

- history of heart disease

- diabetes

- kidney disease

- obese (BMI ≥30)

- significant weight changes in the last 6 months

- use of tobacco products

- pregnant

- on a special diet (gluten free; vegan)

- take any medications for the above conditions

- endurance trained athletes