Sodium-Potassium Ratio Key to Heart Disease Risk, Says Study

A new study linking sodium and potassium intake levels to cardiovascular disease (CVD) sheds new light on our understanding of CVD risk reduction. The study is published in the journal Archives of Internal Medicine.

Researchers from Harvard University, Emory University, and the Centers for Disease Control and Prevention examined data available from 12,267 subjects who participated in the Third National Health and Nutrition Examination Survey (NHANES III). Subjects participated in physical examinations and interviews for diet and lifestyle factors. All subjects were at least 20 years of age and had no history of CVD. Subjects participated in follow-up for an average of 14.8 years.

During the study, 36% of subjects died from CVD.

After adjusting for sex, race, body mass index, and other variables, higher sodium intake was associated with higher CVD mortality rates and higher potassium rates were associated with lower CVD morality rates.

But the combination of high sodium and low potassium created even greater CVD risk than either factor alone. The highest quartile of sodium-to-potassium ratio came with a 46% increased risk of CVD compared to the lowest quartile.

“High sodium levels induce increased blood pressure and hypertension by stiffening endothelial cells, thickening and narrowing resistance arteries, and blocking nitric oxide synthesis, whereas high potassium levels can counteract these effects by activating nitric oxide release,” wrote the study’s author. “The opposite biological effects of sodium and potassium may explain stronger associations of sodium-potassium ratio with CVD mortality than either sodium or potassium intake alone.”

The author noted that previous research on a link between the sodium-potassium ratio and CVD risk has been inconsistent, but this could be due to poorly designed studies.

“Public health recommendations should emphasize simultaneous reduction in sodium intake and increase in potassium intake,” concluded the author.