Dietary sodium and cardiovascular morbidity/mortality: a brief commentary on the 'J-shape hypothesis'

The last decade, a growing number of evidence support J-shape or inverse - instead of positive linear -- associations between dietary sodium intake and cardiovascular morbidity/mortality. A careful evaluation of these studies leads to the following observations: less accurate methods for dietary sodium assessment are usually used; most studies included high-risk participants, enhancing the possibility of a 'reverse causality' phenomenon. However, these limitations do not explain all the findings. Few carefully designed randomized clinical trials comparing different levels of sodium intake that address the issue of the optimal and safe range exist; therefore, current guidelines recommend a higher cut-off instead of a safe range of intake. Given the demonstrated harmful effects of very low sodium diets leading to subclinical vascular damage in animal studies, the 'J-shape hypothesis' cannot yet be either neglected or verified. There is a great need of well-designed general population-based prospective randomized clinical trials to address the issue.

Automated summary

Recent studies suggest a J-shape or inverse relationship between dietary sodium intake and cardiovascular morbidity/mortality, rather than a linear one. Limitations in current research include less accurate assessment methods and inclusion of high-risk populations, but these do not explain all findings. Well-designed prospective randomized clinical trials in general populations are needed to address this issue effectively.