Salt, arterial pressure, and cardiovascular and renal damage

This brief review deals with some novel developments regarding the possible role of salt in the pathogenesis of cardiovascular and renal disorders. Studies in both humans and experimental animals are discussed. Increased salt intake is usually associated with an increase in arterial pressure although some controversies still exist. Salt sensitivity of arterial pressure (defined as an increase in arterial pressure on dietary salt overload) was demonstrated in many animal species as well as in humans. However, findings in rats, the most often used animal model, also demonstrated that this salt sensitivity was not uniform; some strains are salt sensitive, while other strains are salt resistant. Salt sensitivity of arterial pressure in humans is also not uniform; less than one-third of normotensive individuals and less than one-half of hypertensive individuals are salt sensitive. Of great importance are findings that excessive salt intake may damage target organs (cardiovascular system and kidneys) irrespective of arterial pressure. Together with an ever-growing consensus that sodium intake in acculturated societies is high, these findings also emphasize the need for reduction in salt intake. Therefore, the adverse cardiovascular and renal effects of salt continue to be a subject of intense study. Current data indicate that a reduction in salt intake should ameliorate, if not prevent, cardiovascular and renal morbidity and mortality, particularly among individuals with hypertension.