Abstract
The central focus of this review is the fact that the nutritional requirement for sodium in healthy adult mammals outside their reproductive period is unlikely to exceed 0.6 mmol/kg/ day; claims that it is greater in humans imply an unidentified defect in renal sodium conservation. Lack of awareness of nutritional requirement mars the design of many experiments, both on laboratory animals and clinical trials, with arbitrary attribution of groups to ‘low’ or ‘high’ intakes, the latter often absurdly high. Much of the problem arises from misplaced confidence that excess sodium is harmlessly excreted and that a generous excess is therefore salutary. Evidence for the link between dietary salt and hypertension is discussed. The focus of concern should be the fact that the age-related rise in human blood pressure is an accompaniment of excess salt intake rather than a natural phenomenon; even avoidance of this rise would exempt many from the need for treatment, later in life. Many of the putative risks of lower sodium intake relate to minorities or to intakes well below requirement, as opposed to those close to it or prudently above. What needs to be avoided is the continuing acceptance of the tradition that intakes exceeding requirement by ten-fold or more need occasion neither questions nor concern.