Dietary sodium reduction: is there cause for concern?

Current dietary guidance includes a recommendation for moderate reduction of sodium (Na) intake of US adults to less than 2400 mg (approximately 100 mmol) per day. The safety of this recommendation tends to be taken for granted, but questions are raised periodically about possible adverse effects. We evaluated the evidence available to address these concerns. Relevant sources were identified through review of policy documents and a systematic MEDLINE search of articles published between 1984 and mid-October 1995. Reviews and commentaries were selected to encompass the spectrum of arguments for or against possible adverse effects. All identified randomized, human intervention trials of Na reduction with at least 6 months' follow up and urinary Na excretion data were included; selected additional evidence was evaluated as needed to address specific issues. Reports of trials were abstracted to describe relevant design features, study populations, level of Na reduction, and comments or data relevant to adverse effects. We found that some concerns were based on short-term, Na-depletion studies and were, therefore, not relevant to moderate Na reduction in the population-at-large. Other concerns were largely speculative and, from our review, were not supported by the combined evidence from 20 randomized Na reduction trials conducted in varied clinical or community settings and involving diverse populations followed for up to 5 years. Overall, we identified extensive data supporting the safety of public health recommendations for moderate Na reduction and none suggesting cause for concern.