The (Political) Science of Salt

Three decades of controversy over the putative blood pressure benefits from salt reduction are demonstrating how the demands of good science clash with the pressures of public health policy. Early studies seemed to support the value of salt reduction, leading to the current recommendation that everyone limit salt intake to no more than 6 grams a day, four less than our current average. But as the studies have improved, the apparent benefits have diminished, while the debate has grown more vitriolic. Advocates of the public-health orthodoxy of salt reduction have often cited only those studies that bolster their position while criticizing the motives of their opponents. (Also see the Perspective on p. 933 by David McCarron, a member of a research team that published an analysis of a national health and nutrition database in Science in 1984 suggesting that salt is harmless.)