Less salt may be fatally counterproductive for people with heart failure

Too little salt is not necessarily better for individuals with heart failure, with the results of a recent meta-analysis suggesting that sodium restriction in this population increases the risk of death.

Pooled data from nine studies showed that participants who followed a diet that limited the intake of sodium to levels below 2.5 grams per day had an 84-percent higher risk of in-hospital mortality as compared with those who followed a diet with a sodium target of at least 2.5 grams per day (relative risk [RR], 1.84, 95 percent confidence interval [CI], 1.46–2.31; p<0.001). [Palicherla A, et al, ACC 2023 Scientific Session & Expo together with World Congress of Cardiology]

Meanwhile, the rate of hospitalization did not differ between the two treatment groups (RR, 1.45, 95 percent CI, 0.99–2.11; p=0.05).

“Our findings showed that restricting dietary sodium to less than the usual recommendation was counterproductive in the management of heart failure,” according to lead study author Dr Anirudh Palicherla, an internal medicine resident at Creighton University School of Medicine in Omaha, Nebraska, US. “This was in line with a recent randomized controlled trial suggesting that restricting sodium more than what we do now doesn’t … lead to better outcomes.”

The US Dietary Guidelines for Americans recommend that most adults limit daily dietary sodium intake to not more than 2.3 grams, which is equivalent to about one teaspoon of table salt. For patients with heart failure, sodium intake restriction is advised to prevent fluid congestion, which may increase the risk of adverse outcomes.

“Limiting sodium is still the way to go to help manage heart failure, but the amount of restriction has been up for debate,” Palicherla noted.

“This study shows that the focus should be on establishing a safe level of sodium consumption instead of overly restricting sodium. In absence of benefit of salt restriction and increased harm, there should be a reconsideration of such recommendations,” he continued.

The nine studies included in the meta-analysis involved a total of 3,499 participants with heart failure. Sodium intake of those in the more restrictive arm varied from about 1.2 grams to 1.8 grams per day. Most of the studies were conducted between 2008 and 2022, except for a single study that was published in 1991.

Palicherla and colleagues acknowledged a significant variability in the study designs used in the clinical trials, such as different participant baseline characteristics, healthcare settings, and methods for tracking sodium intake and health outcomes. Some participants from several studies were required to restrict both their sodium and fluid intakes.

Nevertheless, Palicherla pointed out that the number of studies and total number of participants gave him and his colleagues a high level of confidence in the overall findings.

The authors called for additional studies to help establish the optimal targets for dietary sodium, as well as pinpoint which subgroups of heart failure patients might benefit from greater or less restriction.

A good approach for reducing dietary salt consumption, according to Palicherla, is to eat more fresh fruits and vegetables and to cook with basic ingredients rather than processed, boxed, and canned foods and sauces that often contain high amounts of sodium.

When dining out or buying prepared foods, people should ask for nutrition information or read the food labels to learn which items had the lowest amounts of sodium, Palicherla said.