CHICAGO – A high sodium intake, especially when combined with a low potassium intake, is associated with an increased risk of cardiovascular disease (CVD) and mortality, according to a report in the July 11 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.(1)
According to background information in the article, previous trials and studies have demonstrated apparent associations between increased blood pressure and high sodium intake or low potassium intake.
“Recently, several studies suggested that the ratio of sodium to potassium intakes represented a more important risk factor for hypertension and CVD than each factor alone,” write the authors. “Examining the joint effects of sodium and potassium intakes on CVD risk is particularly important because most of the U.S. population consumes more sodium and less potassium daily than recommended.
Quanhe Yang, Ph.D., from the Centers from Disease Control and Prevention, Atlanta, and colleagues used data from the Third National Health and Nutrition Examination Survey Linked Mortality File. They selected the data from 12,267 participants for analysis based on dietary information, demographic characteristics and health history.
The data set also included mortality status matched to the participants. The researchers analyzed the data to determine consumption of sodium and potassium, as well as the sodium-potassium ratio, and to further determine the relationship between these variables and the risk of all-cause mortality as well as CVD and ischemic heart disease (IHD) mortality.
After an average follow-up period of 14.8 years, 2,270 of the participants had died; 825 of the deaths were attributed to CVD and 433 to IHD.
Researchers found several characteristics associated with a higher sodium-potassium ratio, including male sex, younger age, status as a smoker and ethnic background. After adjusting for other variables, a higher sodium intake was related to increased all-cause mortality, and a higher potassium intake was associated with a lower mortality risk.
The risk of CVD and IHD was significantly associated with a higher sodium-potassium ratio.
“In summary, 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,” write the authors. “Public health recommendations should emphasize simultaneous reduction in sodium intake and increase in potassium intake.”
1) Arch Intern Med 2011: 171 (13): 1183-1191
Dr. Jonny Comments:
The relationship of sodium to potassium is somewhat similar to the relationship between omega-6 fatty acids and omega-3’s. Neither is “bad”. Both are necessary. The problem is the balance between the two.
We do best with a ratio of about 1:1 when it comes to both omega-6: omega-3 and when it comes to sodium: potassium. However in our modern diet, we consume many many times more omega-6’s than omega-3’s and we consume far more sodium than we do potassium. Processed foods, canned foods and prepared foods are absolutely loaded with sodium, while potassium comes primarily from vegetables and fruits.
While it’s probably prudent to consume less sodium in general, it’s worth noting that a big part of the “sodium” problem is that we’re not getting enough potassium. This study indicates that the ratio is just as important, and suggests that lowering sodium intake is only half the problem- the other is increasing our intake of potassium, one of the most important minerals for heart health.