Low-sodium diet linked to mortality

by Hans Pinckaers

A recent study in the New England Journal of Medicine reports that too much salt is bad for you, which we kinda expected. However too little salt intake is just as bad, which goes against the widely used advice to patients with high blood pressure to adhere to a low-sodium diet.

The lowest risk of death and cardiovascular events was seen among participants with an estimated sodium excretion between 3 g per day and 6 g per day. Both higher and lower levels of estimated sodium excretion were associated with increased risk, resulting in a J-shaped association curve.

Martin O’Donnell, M.B. et al. Urinary Sodium and Potassium Excretion, Mortality, and Cardiovascular Events (NEJM 2014; 371:612-623)

These studies always makes me afraid that a lot of medical protocols are actually based on general wisdom among physicians instead of real evidence. We may think we understand enough about pathofysiology of diseases to guess what treatment will result in the best outcomes, but this study underlines the need for actual studies, even for therapies that just seem too logical not to do. Which makes me wonder: are we even close to genuine evidence-based medicine?