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Too Much Salt, Too Little Potassium Linked to Heart Risk
Americans consume too much sodium and not enough potassium, raising their risk of death from any cause by 50% and doubling their risk of death from heart attacks, according to a new study.
According to Elena Kuklina, MD, PhD, a nutritional epidemiologist with the Centers for Disease Control and Prevention's' Division for Heart Disease and Stroke Prevention and an investigator on the study, the findings from the study are particularly troubling because American adults consume more than twice the amount of sodium recommended for most people.
This study is the first to examine the association between mortality and people's typical intake of sodium and potassium using a nationally representative sample. Dr. Kuklina and the other investigators followed over 12,000 U.S. adults who participated in the Third National Health and Nutrition Examination Survey from 1988 to 1994. NHANES data is based on dietary recall from in-person and telephone interviews as well as self-administered surveys.
Study participants were followed for 15 years and death certificate data was used to see who died and to determine the cause of death. During the follow-up, 56% of the people died from cardiovascular disease.
Participants in the highest sodium intake group (more than 5,000 milligrams a day) had a 73% higher risk of death from any cause compared to those in the lowest sodium intake group (2,176 milligrams a day). People who consumed the most potassium (4,069 milligrams a day) had a 49% lower risk of death from any cause compared to those who took in only 1,793 milligrams a day, leading the researchers to conclude that the more potassium one consumes, the lower their risk of heart disease.
The study, conducted by researchers at the Centers for Disease Control and Prevention, Emory University, and Harvard University, also looked at the sodium-potassium ratio of the study participants and found those who consumed the most sodium and the least amount of potassium (the worst ratio) doubled their risk of death from heart disease and had a 50% greater risk of death from any cause.
On average, Americans consume 3,300 milligrams of sodium per day. The 2010 Dietary Guidelines for Americans recommend limiting sodium intake to 1,500 milligrams per day for people age 51 and above, African Americans, and people with high blood pressure, diabetes, or chronic kidney disease. This applies to about half of the U.S. population over the age of two years. Everyone else is advised to limit their sodium intake to 2,300 milligrams per day.
The dietary guidelines also recommend that Americans consume more foods rich in potassium, and suggests 4,700 milligrams of potassium per day. American women consume about half the recommended amount while American men consume about two-thirds.
Controversy surrounds current recommendations to limit sodium intake to the levels recommended by the 2010 Dietary Guidelines for Americans (1,500 milligrams per day). Research about sodium and heart disease has resulted in contradictory results. It is not clear whether high sodium intake or low potassium intake causes the greater risk for high blood pressure, and research about a connection between sodium and potassium intake and cardiovascular disease has not been consistent.
Until the answers are clearer, Americans would be wise to limit their intake of processed foods high in sodium like canned soups, frozen and boxed dinners, lunchmeat and other processed meats, restaurant meals, chips, and crackers. Increasing potassium intake can be accomplished by eating more fruits and vegetables, yogurt, and milk.
The study was published in the July 11, 2011 issue of the Archives of Internal Medicine.
July 29, 2011