Dietary sodium restriction: still searching for the grains of truth. The reply (original) (raw)

2014, The American journal of medicine

We thank Hummel and Weder for their response 1 to our article 2 pertaining to the potential harms of restricting dietary sodium. The 2 doctors suggest there is a lack of sound evidence that low-sodium diets increase hospitalizations and mortality versus normal-sodium diets because the trials cited in our review used unusual diuretic dosing. Specifically, Hummel and Weder are concerned about high doses of furosemide not commonly used in the United States or Europe. However, in the largest randomized trial we cite (n ¼ 1771), investigators gave furosemide at a dose of 50 mg twice daily (ie, 100 mg/d) to approximately two thirds of all enrolled patients. 3 This dose is well within doses commonly used in Western clinical practice, and the adverse outcomes seen in the trial despite such reasonable therapy raise concern about the safety of concomitant sodium restriction. Hummel and Weder also suggest, without citing any literature specifically, that there are "abundant data.that at least some persons would greatly benefit from dietary sodium restriction." We assume that the physicians are referring to trials reporting "benefit" with regard to the selective surrogate outcome of blood pressure (ignoring adverse effects for other surrogate outcomes 4). However, improvements in any surrogate outcomes do not necessarily translate to improvements in patient-oriented outcomes that matter most (ie, morbidity and mortality). As a number of studies have shown, severe sodium restriction may adversely affect patient-oriented outcomes. 5-8 Last, Hummel and Weder note that, contrary to our arguments, it is indeed "possible" to restrict sodium intake in a meaningful way in the general population. Although some degree of sodium restriction may be possible in the shortterm, whether human physiology will allow maintenance of meaningful restrictions in the long-term is a matter of some debate. Human sodium intake occurs in a remarkably narrow range across diverse populations, eating habits, and time. 9 Regardless, even if long-term population-wide sodium restriction was possible, we are most concerned about the wisdom and safety of such action. The evidence for benefit is lacking, and we agree with Hummel and Weder that "additional research.is needed." Until the findings of such research are available though, we maintain that it is premature to support attempts to markedly reduce sodium intake among the general population.