Indeed, the results of a study published in the American Journal of Hypertension found that, compared with the usual sodium intake throughout the world, those consuming more or less sodium were at increased risk of both all-cause mortality (ACM) and CVD.
For the study, the researchers examined the association of sodium intake and mortality in order to identify a range where the risks of inadequacy and of excess are minimal. Using data from 25 different studies, they investigated the incidence of all-cause mortality (ACM) and cardiovascular disease (CVD) events in populations exposed to dietary intakes of low sodium (<115 mmol); usual sodium (subdivided into low usual: 115–165 mmol and high usual:166–215 mmol); and high sodium (>215 mmol).
The risks of ACM and CVD events decreased in usual sodium versus low sodium intake and increased in high sodium vs. usual sodium intake. Furthermore, there was no difference in outcomes between the higher and lower sodium intake groups within the usual range of sodium intake. Both low sodium intakes and high sodium intakes are associated with increased mortality, consistent with the so-called U-shaped association between sodium intake and health outcomes.
According to the results, the harmful effect associated with a high sodium intake was stronger than the harmful effect associated with a low sodium intake. However, in population-representative samples adjusted for multiple confounders, the pattern was the opposite.
“Our study extends the  IOM report by identifying a specific range of sodium intake (2,645–4,945 mg) associated with the most favorable health outcomes, within which variation in sodium intake is not associated with variation in mortality,” the researchers wrote. “Moreover, this optimal range of intake, based upon available evidence, is coterminous with the current dietary intake of most of the world’s population and is in accordance with the IOM rules for definition of an AI and UL of sodium.”
Source: American Journal of Hypertension
“Compared with usual sodium intake, low and excessive sodium diets are associated with increased mortality: a meta-analysis”
Authors: Niels Graudal, Gesche Jürgens, Bo Baslund and Michael H. Alderman