July 12th, 2011
Study Finds High Sodium-Potassium Ratio Strongly Tied to Mortality and CV Disease
The separate roles of sodium and potassium in cardiovascular disease have been extensively observed in epidemiologic studies. Now a study published in the Archives of Internal Medicine examines their joint effect.
Quanhe Yang and colleagues analyzed data from 12,267 adults participating in the Third National Health and Nutrition Examination Survey. As expected, they found that higher sodium intake was associated with an increased risk of death from any cause, while higher potassium intake was associated with a lower risk of death. However, potassium — but not sodium — intake was significantly (and inversely) associated with cardiovascular and coronary mortality. A higher sodium-potassium ratio was strongly tied to all outcomes.
Here are the hazard ratios comparing the highest-quartile with the lowest-quartile sodium-potassium ratios:
- all-cause mortality: 1.46 (CI, 1.27-1.67)
- CVD mortality: 1.46 (CI, 1.11-1.92)
- ischemic heart disease mortality: 2.15 (CI, 1.48-3.12)
The authors point out that salt is frequently added to processed foods, thereby increasing the sodium-potassium ratio, while fruits, vegetables, and dairy products tend to have a lower ratio. Therefore, “a low sodium-potassium ratio may be a marker of high intake of plant foods and lower intake of processed foods.” They conclude that “public health recommendations should emphasize simultaneous reduction in sodium intake and increase in potassium intake.”
In an invited commentary, Lynn Silver and Thomas Farley write that the “safest and preferred pathway” to increase dietary potassium is to increase the “consumption of unprocessed, potassium-rich fruits and vegetables,” but they point out that “years of educational campaigns” have had little impact. Although potassium supplements have beneficial effects, they also carry the risk of hyperkalemia. They recommend that “efforts to reduce sodium artificially added to the food supply during processing should continue, because they have positive impacts on absolute sodium intake and the sodium-potassium ratio and thus should reduce mortality.”