A review paper co-authored by two faculty members in the University of Delaware College of Health Sciences and two physicians at Christiana Care Health System provides evidence that even in the absence of an increase in blood pressure, excess dietary sodium can adversely affect target organs, including the blood vessels, heart, kidneys and brain.
Potential effects on the arteries include reduced function of the endothelium, which is the inner lining of blood vessels. Endothelial cells mediate a number of processes, including coagulation, platelet adhesion and immune function. Elevated dietary sodium can also increase arterial stiffness.
High dietary sodium can also lead to left ventricular hypertrophy, or enlargement of the muscle tissue that makes up the wall of the heart's main pumping chamber, added the scientists. Regarding the kidneys, evidence suggests that high sodium is associated with reduced renal function, a decline observed with only a minimal increase in blood pressure.
Finally, sodium may also affect the sympathetic nervous system, which activates what is often termed the fight-or-flight response.
Approximately 70 percent of the sodium in our diets comes from processed foods, including items that we don't typically think of as salty such as breads and cereals. Also, restaurant food typically contains more salt than dishes prepared at home, so eating out less can help reduce salt intake.