Is a Low-Salt Diet Right for All Patients?

Low-salt diets may increase the risk of cardiovascular disease and death in individuals without hypertension, according to the results of a recent study.

While previous research has suggested a relationship between salt intake, as measured by urinary sodium excretion, and cardiovascular disease and mortality, it is unknown whether this relationship is affected by hypertension status.
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For their study, the researchers analyzed data from 133,118 individuals—63,559 with hypertension and 69,559 without—who participated in 4 large prospective studies. The participants provided morning fasting urine samples and blood pressure measurements.

After a median follow-up of 4 years, 11% of the participants with hypertension and 4% of those without experienced the primary outcome, a combination of death, myocardial infarction, stroke, and heart failure.

Increased sodium intake was associated with larger increases in systolic blood pressure in participants with hypertension compared with individuals without hypertension. In those with hypertension, sodium excretion of 7 g/day or more and excretion of less than 3 g/day were both associated with increased risk of death or cardiovascular disease, compared with sodium excretion of 4-5 g/day. In those without hypertension, higher sodium excretion was not associated with increased risk, when compared with 4-5 g/day, and excretion of less than 3 g/day was associated with significantly increased risk.

“Compared with moderate sodium intake, high sodium intake is associated with an increased risk of cardiovascular events and death in hypertensive populations (no association in normotensive population), while the association of low sodium intake with increased risk of cardiovascular events and death is observed in those with or without hypertension,” the researchers concluded. “These data suggest that lowering sodium intake is best targeted at populations with hypertension who consume high sodium diets.”

—Michael Potts

Reference:

Mente A, O’Donnell M, Rangarajan S, et al. Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies [published online May 20, 2016]. Lancet. doi: http://dx.doi.org/10.1016/S0140-6736(16)30467-6.