The Science upon Which to Base Dietary Sodium Policy

Few nutrient intake recommendations become subjects of heated scientific debate, but sodium is 1 of them. In the absence of sufficient clinical trials focused on sodium intake and health outcomes, studies that used the surrogate marker of blood pressure have been used to support extreme sodium reduction. Under tightly controlled conditions, maximum achievable sodium reduction leads to a 1-6 mm Hg reduction in systolic blood pressure, which presumably leads to reduced cardiovascular disease morbidity and mortality. However, in observational cohort studies that used not blood pressure but actual health conditions as outcomes, the presumed relation between sodium intakes <2500 mg/d was not observed. Thus, the blood pressure effect of sodium restriction can no longer be accepted as a surrogate for health outcomes associated with sodium intake. Evidence that reducing sodium intakes to <2500 mg/d will improve health is needed to justify continuing efforts to modify diet.