Salt intake, plasma sodium, and worldwide salt reduction.

There is overwhelming evidence that a reduction in salt intake from the current level of approximately 9-12 g/d in most countries of the world to the recommended level of 5-6 g/d lowers blood pressure (BP) in both hypertensive and normotensive individuals. A further reduction to 3-4 g/d has a greater effect. Prospective studies and outcome trials have demonstrated that a lower salt intake is related to a reduced risk of cardiovascular disease. Cost-effectiveness analyses have documented that salt reduction is more or at the very least just as cost-effective as tobacco control in reducing cardiovascular disease, the leading cause of death and disability worldwide. The mechanisms whereby salt raises blood pressure and increases cardiovascular risk are not fully understood. The existing concepts focus on the tendency for an increase in extracellular fluid volume. Increasing evidence suggests that small increases in plasma sodium may have a direct effect on BP and the cardiovascular system, independent of extracellular volume. All countries should adopt a coherent and workable strategy to reduce salt intake in the whole population. Even a modest reduction in population salt intake will have major beneficial effects on health, along with major cost savings.