Excess intake of salt (sodium chloride) has an important and probably predominant role in the pathogenesis of raised blood pressure. The evidence is indisputable—on average, as salt intake increases, blood pressure increases. Animal studies, migration studies, ecological studies, longitudinal observational studies, clinical trials, and meta-analyses of trials have confirmed this association.1 The importance of this association cannot be overstated—blood pressure is an aetiologically relevant and modifiable cardiovascular risk factor, which has guided policy makers for decades.

Worldwide, raised blood pressure accounts for around 62% of strokes and 49% of coronary heart disease events.2 Large scale trials and meta-analyses of trials have conclusively shown that several treatments that reduce blood pressure prevent stroke and coronary heart disease.3 This compelling evidence has led numerous authoritative bodies to conclude that salt reduction, through its effects on blood pressure, should also prevent stroke and coronary heart disease. Direct evidence to support calls for salt reduction has been limited, however, so the linked meta-analysis of cohort studies by Strazzullo and colleagues (doi:10.1136/bmj.b4567) is a useful and welcome addition to the medical literature.4

The …