Dietary Sodium: Where Science and Policy Diverge

In 2013, an Institute of Medicine (IOM) Committee, after reviewing available evidence, reached conclusions that differed importantly from conventional belief.1 They reported that while harm exists with “excessive” sodium intakes, the term was specifically left undefined. In addition, they concluded, “evidence was insufficient to support (or refute) previous recommendations for population-based efforts to achieve sodium intake levels of less than 2.3 g/day in the general population or most population subgroups.” While recognizing that blood pressure was a strong surrogate for cardiovascular events, IOM nevertheless concluded that the health effect of of dietary sodium should be determined through assessment of evidence directly linking sodium intake to actual health outcomes—and not through intermediate variables such as blood pressure. Since the IOM report, several additional publications linking dietary sodium to health outcomes have confirmed, clarified, and extended its conclusions.2–6 While observational studies can determine associations, they do not establish causality, and can not generally be a basis for therapeutic intervention. The purpose of this review is to critically assess these recent reports in the context of already available evidence, as well as the IOM report, and to suggest policy options consistent with the evidence. Post IoM studIes