Pathways by Which Dietary Salt Affects Blood Pressure and the Nervous System

Abstract

In their article in this edition of Hypertension , O’Donaughy and Brooks1 address a double controversy, that is, salt-sensitive hypertension and the role of the nervous system in long-term blood pressure control. Although both of these areas of research have avid opponents and proponents, there is an emerging understanding of the multifaceted mechanisms that underlie hypertension in humans and the importance of both dietary NaCl and the nervous system in hypertension. The role of dietary salt intake in hypertension has been widely debated in both the lay and scientific literature for over a half century, and the view of its role has shifted during that period. Much of the evidence against the pathogenic role of salt in hypertension is based on epidemiological and dietary interventional studies that did not discriminate between putative salt-sensitive and salt-resistant individuals. More selective studies have established that salt-sensitive changes in arterial pressure exist in many individuals and that these changes can result in significant health risks. Furthermore, recent studies have demonstrated that salt sensitivity is present more frequently in hypertensive than in normotensive humans and that “normotensive” salt-sensitive individuals have a greater risk of developing hypertension with increasing age. Also, given the latest downward adjustment of the threshold for hypertension by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7), even modest dietary salt-related increases in arterial pressure will thrust into the hypertension category many more individuals than anticipated previously. Thus, salt sensitivity in blood pressure control is real and important. The mechanisms underlying hypertensive responses to chronic high-salt …