Too much or too little sodium may boost CV risk

Patients who had notably high or notably sodium intake levels were at increased risk of both all- cause mortality and cardiovascular disease, compared with patients who had usual sodium intake levels, a new meta-analysis suggests.

In fact, the sodium “sweet spot” may be between 2,645 mg/ day and 4,945mg/day, a range that the report’s investigators noted was “associated with the most favorable health outcomes, within which variation on sodium intake is not associated with variation mortality.”

Researchers explored the association between sodium intake and health outcomes, basing measurements on the average sodium levels of participants from surveys included in the meta-analysis. Data for the analysis included surveys that tracked sodium intake in population samples from prospective cohort studies and randomized controlled studies. The investigators categorized the measurements as low (less than 2,6454 mg/day), usual (between 2,645 mg/day and 4,945 mg/day), and high (more than 4,945 mg/ day) sodium intake levels.

“In none of the primary or supplementary analyses was a low sodium intake associated with beneficial effects on [all-cause mortality] or [cardio vascular disease],” the investigators wrote.

Notably, this estimate is higher than the 2004 Institute of Medicine recommendations used by Centers for Disease Control and Prevention, which set tolerable sodium intake levels at no more than 2,300 mg/day for healthy individuals younger than 50 years, and to 1,500 mg/day for those older than 50 years and other groups at greater risk. However, an IOM study in 2013 concluded that the health effect of lower sodium does not support recommendations to lower sodium intake within these subgroups to or even below 1,500 mg/day.

The result from a meta-analysis of 274,683 patients in 25 studies. The Copenhagen University Hospital led the study. The survey sample included several subsets of data, as well as participants from a wide variety of demographics.

When comparing usual- intake vs. low- intake groups, the risk of all-cause mortality was significantly lower in the usual-intake group, but stroke and heart disease risks were the same for both groups.

Compared with high-intake groups, usual-intake groups had significantly lower risk of all-cause mortality, cardiovascular disease, stroke and heart disease.