• heart failure

There is much evidence that higher sodium intake is associated with elevated blood pressure and there is a strong likelihood that the relationship between excess dietary sodium intake and hypertension is causal.1–3 Corresponding evidence from clinical trials shows that significant reductions in blood pressure can be achieved by lowering dietary sodium consumption in groups with hypertension as well as among normotensive individuals.4 With high blood pressure identified as the leading cause of cardiovascular disease in the world, responsible for more than 60% of stroke events and almost 50% of coronary heart disease,5 efforts to control blood pressure levels have been a global priority for decades. In addition to very well established clinical hypertension control programmes, many of the world's leading scientific and health organisations recommend the widespread reduction of sodium intake for blood pressure lowering. In the USA, the US dietary guidelines recommend reducing the daily intake of sodium to less than 2300 mg/day for the general population, which equates to about one teaspoon or 6 g of salt.6 The US dietary guidelines also advise that higher risk individuals, such as African Americans or people with hypertension, diabetes, or chronic kidney disease, should aim for a daily intake of 1500 mg/day or less.6

A key challenge for these guidelines has been the absence of definitive evidence that reduced dietary sodium translates into lower risks of ‘hard’ clinical outcomes such as stroke and heart attack. This has been the focus of much recent debate. On the one hand, investigators have projected that population-wide reductions in dietary sodium intake will deliver very large benefits because the blood pressure reductions that would ensue would produce substantial reductions in cardiovascular disease.7 It is estimated …