ReviewDietary Sodium Restriction: Take It with a Grain of Salt
Section snippets
Salt and Blood Pressure
Much of the support for the idea that a low sodium diet leads to a lower blood pressure comes from the Dietary Approaches to Stop Hypertension (DASH) study.6 This study enrolled 412 participants and randomly assigned them to receive the control diet or the DASH diet. In both groups, the participants were assigned randomly to a high sodium diet (150 mmol/d), normal sodium diet (100 mmol/d), or low sodium diet (50 mmol/d) for 30 consecutive days and were then crossed over within their assigned
Patient-oriented Outcomes: Morbidity and Mortality
Congestive heart failure is characterized by various processes that lead to reduced renal perfusion and activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system.8 This leads to preferential retention of water compared with sodium and can cause hyponatremia. Restricted dietary sodium intake may further exacerbate these processes, therefore precipitating hyponatremia.
A study9 enrolled 410 patients with congestive heart failure and followed them for 6 months to
Other Unintended Consequences Relevant to Cardiovascular Health
A Cochrane review based on 167 studies showed that a low sodium diet in normotensive whites leads to a small reduction in systolic blood pressure (−1.27 mm Hg; CI, −1.88 to −0.66; P = .0001), without significantly reducing diastolic blood pressure (−0.05 mm Hg; CI, −0.51 to 0.42; P = .85).22 However, a low sodium diet caused an increase in renin (P < .00001), aldosterone (P < .00001), noradrenaline (P < .00001), adrenaline (P < .0002), cholesterol (P < .001), and triglycerides (P < .0008). This
Conclusions
There is no conclusive evidence that a low sodium diet reduces cardiovascular events in normotensive and pre-hypertensive or hypertensive individuals. On the contrary, there is sound evidence that a low sodium diet leads to a worse cardiovascular prognosis in patients with systolic congestive heart failure or type 2 diabetes mellitus. Worldwide sodium restriction, through its adverse effects on insulin resistance, may lead to an increase in the rates of type 2 diabetes mellitus. By potentially
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Authorship: All authors had access to the data and played a role in writing this manuscript.