in a new study.
In the study of more than 500,000 people, compared with those who never or rarely added salt, those who always added salt to their food had a 28% increased risk of dying prematurely (defined as death before the age of 75 years).
Results also showed that adding salt to food was linked to a lower life expectancy. At the age of 50 years, life expectancy was reduced by 1.5 years in women and by 2.28 years in men who always added salt to their food, compared with those who never or rarely did.
However, these increased risks appeared to be attenuated with increasing intakes of high-potassium foods (vegetables and fruits).
The study was published online in the European Heart Journal.
“As far as we are aware, this is the first study to analyze adding salt to meals as a unique measurement for dietary sodium intake. Such a measure is less likely affected by other dietary components, especially potassium intake,” senior author Lu Qi, MD, Tulane University, New Orleans, told this news organization.
“Our study provides supportive evidence from a novel perspective to show the adverse effects of high sodium intake on human health, which is still a controversial topic. Our findings support the advice that reduction of salt intake by reducing the salt added to meals may benefit health and improve life expectancy. Our results also suggest that high intakes of fruits and vegetables are beneficial regarding lowering the adverse effects of salt,” he added.
Link between dietary salt and health is subject of longstanding debate
The researchers explained that the relationship between dietary salt intake and health remains a subject of longstanding debate, with previous studies on the association between sodium intake and mortality having shown conflicting results.
They attributed the inconsistent results to the low accuracy of sodium measurement, noting that sodium intake varies widely from day to day, but the majority of previous studies have largely relied on a single day’s urine collection or dietary survey for estimating the sodium intake, which is inadequate to assess an individual’s usual consumption levels.
They also pointed out that it is difficult to separate the contributions of intakes of sodium and potassium to health based on current methods for measuring dietary sodium and potassium, and this may confound the association between sodium intake and health outcomes.
They noted that the hypothesis that a high-potassium intake may attenuate the adverse association of high-sodium intake with health outcomes has been proposed for many years, but studies assessing the interaction between sodium intake and potassium intake on the risk of mortality are scarce.
Adding salt to food at the table is a common eating behavior directly related to an individual’s long-term preference for salty tasting foods and habitual salt intake, the authors said, adding that commonly used table salt contains 97%-99% sodium chloride, minimizing the potential confounding effects of other dietary factors including potassium. “Therefore, adding salt to foods provides a unique assessment to evaluate the association between habitual sodium intake and mortality.”