January 19th, 2015

Optimum Salt Intake in Elderly Remains Elusive

A new study offers fresh evidence that current salt recommendations should be taken with, well, a grain of salt. Current guidelines now recommend that everyone should have sodium intake levels below 2300 mg per day. For many people at higher risk, including everyone over 50 years of age, sodium intake should be below 1500 mg/d. (The American Heart Association promotes the more rigorous goal of 1500 mg/d for everyone.) But a 2013 report from the Institute of Medicine, along with findings from the PURE study published last year, have raised concerns that the lower target level in particular is neither practical nor beneficial.

The new study, published in JAMA Internal Medicine, looks at the growing and important elderly patient population. The researchers analyzed 10-year followup data from 2,642 adults between 71 and 80 years of age who participated in an observational study and who had their sodium intake assessed based on a food frequency questionnaire filled out in the second year. Median sodium levels were 2850 for men and 2320 for women.

No significant relationship was found between sodium intake and mortality or the development of cardiovascular disease or heart failure. There were trends in favor of moderate sodium intake (1,500  to 2,300 mg/d) compared with very low (<1,500 mg/d) or high (>2,300 mg/d) intake. Overall mortality was 33.8% in the very-low group, 30.7% in the moderate group, and 35.2% in the high group. Similar patterns were observed for cardiovascular disease and heart failure, but at no point did these differences achieve statistical significance.

The authors acknowledged that their study was imperfect, mentioning the well-known limitations of observational studies and the use of a self-reported questionnaire to measure salt intake. But they also pointed out the limitations of the evidence base for the current recommendations.

Considering the special case of older adults, in whom comorbidities, inadequate caloric intake, and medication interactions are additional concerns with very low sodium intake, the effect of sodium restriction should probably be tested explicitly in this population before implementing a generalized recommendation for very low (<1500 mg/d) sodium intake target.”

Until “stronger evidence, preferably from rigorous controlled trials,” is obtained, they recommend that “a more conservative approach to sodium restriction (e.g., targeting “<2300 mg/d) might be appropriate for older adults.”


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