Link of High Sodium and Low Potassium Diets to Heart Disease

Several studies have shown that high intake of sodium and low intake of potassium in the diet can raise the risk of heart disease. However, there is little or no research on their effect on the risk of mortality. The present study followed-up participants for nearly 15 years and documented 2,270 deaths. Further analysis of the risk factors involved showed that high sodium raised the risk of mortality, while high potassium lowered the risk. This was the same across sexes, races and ethnicities, body weights, blood pressure statuses, education and exercise levels.

High dietary sodium or low potassium levels raise the risk of high blood pressure and heart disease. Many studies have linked heart disease and associated deaths to high blood pressure. However, there have been no concrete studies on the association between sodium and potassium levels and the risk of death due to heart disease. The ratio of sodium and potassium is vital in the maintenance of heart health. This study tracked a population of 20 year-olds over nearly 15 years to see the effects of the ratio of sodium and potassium on the incidence of heart disease, heart attacks and related deaths.

* The participants in this study belonged to the Third National Health and Nutrition Examination Survey Linked Mortality File, which spanned the years between 1988 and 2006.
* The study involved 12,267 adult Americans who were regularly assessed for an average of 14.8 years. Information on their demographic, dietary and health characteristics was recorded. They underwent regular clinical examinations.
* Details of dietary composition were obtained to estimate their sodium and potassium consumption at the beginning of the study. Risk factors linking the intake of sodium and potassium in the diet and heart disease outcomes were computed.

Key findings
* During the follow-up period, 2,270 deaths were recorded among the study population. Of these, 825 were due to cardiovascular disease and 443 were due to ischemic heart disease.
* Higher sodium intake increased the risk of death. Conversely, higher potassium intake lowered the risk of death.
* The level of risk did not vary with gender, race or ethnicity, body mass index, blood pressure status, education and levels of regular physical activities.

Next steps/Shortcomings
Authors admit that they did not study the changes that could have occurred in the levels of sodium and potassium intake over time. This could have skewed the results. In addition, the participants did not report their use of raw table salt.  Another limitation of this study, as cited by authors, is that other diet related good and bad habits were not assessed. Furthermore, assessment of 24-hour urine samples was not done to determine the actual sodium and potassium intake.

This study shows that high sodium and low potassium in the diet are linked to high rates of death, resulting from cardiovascular disease and heart attacks. It shows that the ratio of sodium and potassium, rather than each element alone, determines the risk of death due to heart disease and high blood pressure in the American population. The authors recommend that public health directives should take these findings into consideration and advise a reduction in sodium intake, while encouraging an increase in potassium intake through diet. This is essential for the effective prevention of high blood pressure, heart disease, and the subsequent predisposition to heart attacks and deaths due to cardiovascular disease.

For More Information:
Sodium and Potassium Intake and Mortality among U.S. Adults
Publication Journal: Archives of Internal Medicine, July 2011
By Quanhe Yang, PhD; Tiebin Liu; Office of Public Health Genomics, Atlanta, Georgia

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