Is Strict Salt Limit Necessary For Older Adults?

Andreas Kalogeropoulos, MD MPH PhD Assistant Professor of Medicine (Cardiology) Emory University School of Medicine Emory Clinical Cardiovascular Research Institute Atlanta GA Interview with:
Andreas Kalogeropoulos, MD MPH PhD

Assistant Professor of Medicine (Cardiology)
Emory University School of Medicine Emory Clinical Cardiovascular Research Institute
Atlanta GA 30322

Medical Research: What is the background for this study? What are the main findings?

Dr. Kalogeropoulos: There is ongoing debate on how low should we go when it comes to dietary sodium (salt) restriction recommendations. In this study, we examined the association between self-reported dietary sodium intake and 10-year risk for death, cardiovascular disease, and heart failure in approximately 2,600 adults 71-80 years old. The subjects (women: 51.2%; white: 61.7%; black: 38.3%) were participants of the community-based Health, Aging, and Body Composition Study, which is sponsored by NIH and focuses on aging processes, i.e. was not specifically designed to address the issue of dietary salt intake. Also, it is important to note that salt intake was self-reported (not objectively measured) using a food frequency questionnaire, which underestimates salt intake. Keeping these limitations in mind, we did not observe a significant association between self-reported sodium intake and 10-year mortality, cardiovascular disease, and heart failure. Ten-year mortality was lower in the group reporting 1500–2300 mg daily sodium intake (30.7%) compared to those reporting daily intake less than 1500 mg (33.8%) or over 2300 mg (35.2%); however, this difference was not statistically significant. The 10-year event rates for cardiovascular disease (28.5%, 28.2%, and 29.7%) and heart failure (15.7%, 14.3%, and 15.5%) were also comparable across the <1500-mg, 1500-2300-mg, and >2300-mg dietary sodium intake groups.

Medical Research: What should clinicians and patients take away from your report?

Dr. Kalogeropoulos: The current CDC guidelines for dietary sodium intake, i.e. <2300 mg for the general population (corresponding to 6 grams or a teaspoon of salt) with <1500 mg reserved for high risk groups, including older adults, are probably the best approach until more data are available. Although our findings do not support the strict (<1500 mg daily) sodium restriction recommendation for the general population of older adults, there was no signal of harm either. However, a more conservative approach to sodium restriction (that is, targeting <2300 mg/d) might be appropriate for older adults until more data become available. Of note, our findings do not apply to older adults with pre-existing cardiovascular disease or heart failure.

Patients should not interpret our findings as a “license” to consume more salt. First, average dietary salt intake is already too high in most Western or westernized communities and well above the average reported intake in our study. Second, there is no question whether moderating salt intake provides health benefits. We know that going from high-salt (e.g. 12 g or two teaspoons a day) to low-salt (6 g or one teaspoon a day) diet is good for health. We are now trying to fine-tune the most appropriate level of “low” that provides the most benefit, i.e., would that be 6 g a day or lower? Third, high salt intake (i.e., far more than a teaspoon daily) was associated with a trend towards increased mortality in our study, too; we just did not have enough participants in this category to be statistically confident about these trends. Therefore, patients should follow the current guidelines and consult with their healthcare provider as the best approach.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Kalogeropoulos: Our study is not the first to cast doubt on the strict (<1500 mg daily) sodium intake recommendation — although it is the first one to look at older adults specifically. Considering the special case of older adults, in whom comorbidities, inadequate caloric intake, and medication interactions are additional concerns with very low sodium intake, we probably need to test the effect of sodium restriction on outcomes explicitly in this special population before implementing a generalized recommendation for very low (<1500 mg/d) sodium intake. Of note, the Institute of Medicine has highlighted the lack of data on the appropriate level of sodium restriction for older adults and other special populations, including patients with pre-existing heart failure. In the latter, a limited number of studies to date has not corroborated the traditional recommendation for sodium restriction, highlighting the need for more rigorous studies and more definitive evidence in special populations.


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