Salt and hypertension at the close of the millenium.
"Can that which is unsavory be eaten without salt?" This question was directed at none other than God by Job, who also had other important problems to ponder. The question posed in this review is the notion that essential hypertension is induced and/or sustained by an unnecessarily high salt intake. If this is indeed the case, then a reduction of salt intake might prevent or effectively treat essential hypertension. A cross-sectional epidemiological study of salt intake in populations showed a positive association of sodium excretion with median blood pressure and the prevalence of hypertension; however, when four disparate populations were deleted, the associations disappeared. A Scottish report on a similarly large population minimized the importance of dietary sodium. A recently analysis of the National Health and Nutrition Examination Survey (NHANES) data base does not support the idea that lower salt intake improves all-cause or cardiovascular mortality; however, the analysis is not without weaknesses. Salt-sensitivity is based on the idea that some persons might be more susceptible to salt-induced effects on blood pressure than others. Indeed, several monogenic syndromes exhibit marked salt-sensitivity and their clarification has facilitated our understanding of basic mechanisms. Allelic variants of several genes may be important in salt-sensitive patients with essential hypertension. Meta-analyses of intervention trials in patients with essential hypertension show about a 5 mm Hg decrease in blood pressure with salt restriction. Among the normotensive, this decrease is less than 2 mm Hg. In terms of efficacy, salt restriction has not been shown superior to weight loss or a "vegetable" diet. Nonpharmacological approaches in hypertensive patients should be based on a comprehensive approach.
Luft
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Franz Volhard Clinic, Max Delbrück Center for Molecular Medicine, Medizinsche Fakultät der Charité, Humboldt University of Berlin, Federal Republic of Germany. luft@fvk-berlin.de
D004039:Diet, Sodium-Restricted; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000517:prevention & control; D012306:Risk; D017673:Sodium Chloride, Dietary / Q000009:adverse effects*
D017673:Sodium Chloride, Dietary