Restricting salt is one of the most popular preventive strategies against heart failure (HF). In a new study, however, researchers found that the said dietary recommendation may actually provide more harm than good.
Sodium restriction is widely advised by clinicians for individuals at risk of heart failure, but the truth is there is no sufficient evidence to support it. Researchers from Rush University Medical Center then embarked on an investigation to determine the effects of sodium restriction among patients.
The verdict? They did not find proof supporting the benefits of restricting salt. In fact, hospitalization rates and the risk of death due to heart failure were higher (42.3 percent) in salt-restricted patients than the salt-unrestricted group (26.2 percent).
The authors also discovered that the risk of hospitalization is higher in salt-restricted than unrestricted participants, with 32.3 percent and 20 percent respectively.
The said results persisted even after the researchers made several adjustments.
To come up with the results, the scientists analyzed data from Heart Failure Adherence and Retention Trial. The said tool evaluated the effectivity of self-management counselling in 902 HF patients within a median follow-up of 36 months.
The participants were divided into two groups: the sodium-restricted (with salt intake of less than 2,500 mg/d) and the sodium-unrestricted (with salt intake of 2,500 mg/d or higher). The groupings were made based on a food frequency questionnaire, which the participants accomplished.
The results may seem counterintuitive but the authors wrote that these were supported by numerous evidences. For example, a small study in the past concluded that sodium restiriction was not able to reduce hospital days and improve the condition of patients with HF.
In another large Italian study, low sodium intake resulted in reduced diuresis or urination, more HF readmissions, poorer renal conditions and higher mortality rates after discharge.
The authors said their findings support the downgrade of guidelines made by the American College of Cardiology Foundation/American Heart Association regarding sodium restriction for patients with HF. The results also calls out for a further randomized, multicenter investigation to determine the role of sodium in HF management once and for all.
In 2009, sodium restriction was categorized as Class I recommendation based on expert consensus alone. In 2013, the guidelines demoted the strategy to Class IIa based on the same level of proof.
A number of experts commented on the new study but conveyed only one major point: the role of sodium in HF management is not yet certain and experts need to work on it seriously.
"The current study adds to the momentum to call the question but does not provide answers," said Clyde Yancy from Northwestern University.
For Dr. Salim Yusuf from McMaster University in Hamilton, Ontario, it may be prudent to stop lowering sodium intake recommendations drastically while hazards and benefits are not yet confirmed. "The issue is no longer who is right, but what is right," he said.
The study was published online in the January 2016 issue of JACC: Heart Failure.
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