It is not clear whether lowering dietary salt intake actually helps patients with heart failure, according to a review in JAMA Internal Medicine.

Researchers reviewed nine trials that randomised nearly 500 patients with heart failure to restricted sodium intake or to a control group. There was little evidence supporting a low-sodium diet in terms of cardiovascular and all-cause mortality and cardiovascular-associated events. Two of the trials reported improvements in NYHA functional class with a restricted-sodium diet.

Dr. Harlan Krumholz, editor-in-chief of NEJM Journal Watch Cardiology, said in an email that this is "an important study for what it does not find, which is a lack of evidence to support salt restriction. For all the burden we have imposed on patients with this strategy, it turns out we have too little evidence to support the practice."