High salt diet increases risk of CVD, death: Study

The study, published in JAMA’s Archives of Internal Medicine​, reports that a high sodium-potassium intake ratio is associated with significantly increased risk of cardiovascular disease (CVD) and all-cause mortality, whilst high sodium intake is associated with increased total mortality.

“In this cohort of a nationally representative sample of US adults followed for an average of 14.8 years, we observed a significant monotonic association between increasing sodium-potassium ratio and risk for all-cause, CVD, or IHD mortality. This association was independent of age, sex, race/ethnicity, and other covariates,”​ said the authors, led by Dr. Quanhe Yang, from the Centers from Disease Control and Prevention, USA.

“Our findings indicate that higher sodium-potassium ratio is associated with significantly increased risk of CVD and all-cause mortality in the general US population … Public health recommendations should emphasize simultaneous reduction in sodium intake and increase in potassium intake,”​ they added.

Study details​

Sodium and potassium consumption, as well as the sodium-potassium ratio, in more than 12,000 US citizens in order to determine the relationship between these variables and the risk of all-cause mortality as well as cardiovascular disease CVD and ischemic heart disease (IHD) mortality.

The researchers reported that after adjusting for other variables such as smoking status and age, higher sodium intake was related to increased all-cause mortality, whilst a higher potassium intake was associated with a lower mortality risk.

The risk of death from cardiovascular disease and ischemic heart disease was also significantly associated with a higher sodium-potassium ratio, said Yang and his colleagues.

“Our findings indicate that higher sodium-potassium ratio is associated with significantly increased risk of CVD and all-cause mortality in the general US population,”​ they added.

Mixed message?​

The new study comes only days after a systematic review from the highly regarded Cochrane collaboration (reported here​) suggested that there is not yet enough evidence to show that reducing salt intake reduces the incidence of cardiovascular disease or all cause mortality.

The findings of the Cochrane review were slammed as “completely inappropriate”​ by Consensus Action on Salt and Health (CASH) campaign director Katharine Jenner, who told FoodNavigator that it was “very disappointing”​ to see the message from the review indicates that salt reduction may not be beneficial.

Speaking to FoodNavigator about the new study, Professor Graham MacGregor, Chairman of World Action on Salt and Health (WASH) said that the new study was a larger and better performed study than others that have been recently published.

“The new study also confirms the additional benefits of increasing potassium intake if sodium intake is high … Although the biggest benefits will come from salt reduction, which industry has shown they can do, the benefits of a better sodium to potassium ratio by improving sodium should also be highlighted,”​ said MacGregor.

Writing in an invited commentary piece in the Archives of Internal Medicine​, Dr. Thomas Farley of the New York City Department of Health and Mental Hygiene, USA, said that the new study “strengthens the already compelling evidence of the relationship between sodium intake and mortality.”​

He added that the study “challenges us to clarify effective public health strategies”​ for salt reduction.

“It is crucial that we understand the interplay of sodium and potassium in the diet and how to optimize intake in an increasingly processed food supply without generating harm,”​ said Farley.

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Study source: Archives of Internal Medicine​
Volume 171, Issue 13, Pages 1183-1191
“Sodium and Potassium Intake and Mortality Among US Adults: Prospective Data From the Third National Health and Nutrition Examination Survey”​
Authors: Q. Yang, T. Liu, E.V. Kuklina, W.D. Flanders, Y. Hong, C. Gillespie, et al.

Invited comment source: Archives of Internal Medicine​
Volume 171, Issue 13, Pages 1191 – 1192
“Sodium and Potassium Intake: Mortality Effects and Policy Implications”​
Authors: L.D. Silver, T.A. Farley