The University of Haifa, Israel
Micah Leshem has completed his PhD from Leeds University, and since 1977 he has been at the University of Haifa. His interests include transgenerational and developmental aspects affective behavior. Sodium appetite over the lifespan in laboratory rats and humans is another of my abiding interests, reflected in over 30 of his publications.
Salt intake is deranged because humans ingest vast quantities of it with no clear utility - and despite much evidence of its deleterious effects. We review the paucity of ideas as to why this occurs, and make some novel suggestions. The consensus that dietary sodium is toxic, and the contention that it is not, fuel an important debate that, astonishingly, ignores its root cause - why humans eat salt in the first place. What high salt intake causes is well researched, what causes high salt intake is not known at all. There have been very many and extensive studies on tens of thousands of people over at least 4 decades elucidating and refining the connection between sodium intake and pathology, and there has been considerable public investment in health promotion and legislation to reduce sodium dietary content and intake. Despite this tremendous investment, in the same period only 3 review articles have addressed the causes of human sodium appetite, and consensually concluded that ‘‘we know of no reason for intake of salt in humans’’. Hence, essentially, the efforts to manage sodium consumption, by the individual, the physician, and government, are not evidence-based. The study of the causes and determinants of salt appetite will assist in addressing its behavioral regulation, largely sodium over-consumption, but also the increasingly recognized probleMS of hyponatremia and fluid regulation, neonatally, in exertion, in disease, in mental anguish, and in senescence. We will touch upon these aspects of sodium intake as an alternative conceptualization of the causes of our deranged intake of salt.