Dietary Sodium and Cardiovascular Disease

Andrew Smyth, Martin O’Donnell, Andrew Mente, Salim Yusuf

Although an essential nutrient, higher sodium intake is associated with increasing blood pressure (BP), forming the basis for current population-wide sodium restriction guidelines. While short-term clinical trials have achieved low intake (<2.0 g/day), this has not been reproduced in long-term trials (>6 months). Guidelines assume that low sodium intake will reduce BP and reduce cardiovascular disease (CVD), compared to moderate intake. However, current observational evidence suggests a J-shaped association between sodium intake and CVD; the lowest risks observed with 3-5 g/day but higher risk with <3 g/day. Importantly, these observational data also confirm the association between higher intake (>5 g/day) and increased risk of CVD. Although lower intake may reduce BP, this may be offset by marked increases in neurohormones and other adverse effects which may paradoxically be adverse. Large randomised clinical trials with sufficient follow-up are required to provide robust data on the long-term effects of sodium reduction on CVD incidence. Until such trials are completed, current evidence suggests that moderate sodium intake for the general population (3-5 g/day) is likely the optimum range for CVD prevention.