Salt intake, blood pressure and clinical outcomes

Salt intake has long been known to influence blood pressure among hypertensive patients, but its effect among those without overt hypertension, as well as its effects on cardiovascular disease itself, have been disputed. This report reviews the evidence for an effect on both blood pressure and cardiovascular disease, particularly among normotensive participants, including recent data from randomized trials.

The Dietary Approaches to Stop Hypertension study provided clear evidence for a short-term effect of sodium on blood pressure among those with and without hypertension. Longer term trials among nonhypertensive particpants suggest more modest effects of lifestyle sodium reduction interventions on blood pressure. The recent Trials of Hypertension Prevention follow-up study found that, despite small changes in blood pressure, the risk of cardiovascular disease was reduced by 25% among those in the sodium reduction intervention. A study of potassium salt substitution among Taiwanese veterans supports this finding. Sodium and potassium may act jointly in the development of hypertension and cardiovascular disease.

Average sodium consumption in the US population is excessively high, and well above recommended limits. Because most sodium derives from processed and restaurant foods, a reduction of sodium in these sources, as recently called for by the American Medical Association, is necessary to reduce exposure.