For years, doctors have advised heart failure patients to reduce their salt intake as a way to preserve their health. But a new study suggests that reducing salt intake may be harmful and potentially increase a heart failure patient's risk of death or hospitalization.
The researchers found that patients with moderate heart failure who followed a low-sodium diet were 85 percent more likely to die or require hospitalization for heart disease compared to similarly ill patients who did not follow a low sodium diet.
‘About 42 percent of heart failure patients following a low-sodium diet are more likely to die or hospitalized for heart problems when compared to 26 percent of patients with no salt restrictions.’
Lead researcher Dr. Rami Doukky, a cardiologist and associate professor at Rush University Medical Center in Chicago, said, "The conventional wisdom has been that salt is not good for you. This study says, not so fast. Maybe we should take that; no pun intended, with a grain of salt."
However, the author warned that the study findings are very preliminary and should not be interpreted by heart failure patients to mean that they can include more salt. Cardiologists said that rigorous clinical trials were needed to test further the safety of this hypothesis.
"The study is meant to be an eye-opener, which we need to investigate this matter more. We used to take it [salt consumption] for granted, and now it is time to address it with more definitive trials," said Doukky.
Doctors have long assumed that salt is bad for heart failure patients as it causes the body to retain water and pull additional fluid into the blood vessels, Doukky explained.
"Physiologically, the assumption makes sense," said Dr. Clyde Yancy, chief of cardiology at Northwestern University's Feinberg School of Medicine in Chicago.
According to the U.S. National Institutes of Health, heart failure patients struggle with fluid retention because their heartbeats are weak to fight the force of gravity, allowing blood and water to build up in their lungs, feet, ankles and legs.
The American Heart Association stated that salt also increases blood pressure by drawing water into the arteries and veins, which is a long-known risk factor for heart disease.
However, a handful of recent studies have called those long-held assumptions into question, suggesting that a low-sodium diet might actually be harmful to heart failure patients, said Doukky.
To put it to the test, Doukky and his colleagues gathered data from a clinical trial that followed heart failure patients an average of three years and tracked their salt intake using a food questionnaire.
The researchers examined 833 patients from the study, including 130 patients who followed a sodium-restricted diet. They were matched against 130 patients who never followed a low-sodium diet.
The researchers found that about 42 percent of heart failure patients following a low-sodium diet wound up dying or hospitalized for heart problems, compared to 26 percent of patients with no salt restrictions.
"To our surprise, we found that patients who were sodium-restricted had worse outcomes than those who were taking sodium more liberally," said Doukky.
"The idea is sodium restriction leads to a contraction of the fluid volume in the body, and that turns on certain hormones that try to retain fluids in the body and may potentially accelerate the heart failure process," he added.
The study findings were published in JACC: Heart Failure
, a journal published by the American College of Cardiology.