Salt and public health: contested science and the challenge of evidence-based decision making.

For more than four decades, starting in the late 1960s, a sometimes furious battle has raged among scientists over the extent to which elevated salt consumption has adverse implications for population health and contributes to deaths from stroke and cardiovascular disease. Various studies and trials have produced conflicting results. Despite this scientific controversy over the quality of the evidence implicating dietary salt in disease, public health leaders at local, national, and international levels have pressed the case for salt reduction at the population level. This article explores the development of this controversy. It concludes that the concealment of scientific uncertainty in this case has been a mistake that has served neither the ends of science nor good policy. The article poses questions that arise from this debate and frames the challenges of formulating evidence-based public health practice and policy, particularly when the evidence is contested.