The study, published Monday in the Archives of Internal Medicine, found those who eat a diet high in sodium and low in potassium have a 50 percent increased risk of death from any cause.
Researchers at the Centers for Disease Control and Prevention in Atlanta, Emory University in Atlanta and Harvard University in Cambridge, Mass., analyzed data from the National Health and Nutrition Examination Survey.
"The study's findings are particularly troubling because U.S. adults consume an average of 3,300 milligrams of sodium per day, more than twice the current recommended limit for most Americans," Dr. Elena Kuklina, with the CDC, says in a statement.
"This study provides further evidence to support current public health recommendations to reduce sodium levels in processed foods, given that nearly 80 percent of people's sodium intake comes from packaged and restaurant foods. Increasing potassium intake may have additional health benefits."
U.S. dietary guidelines recommend consuming less than 2,300 milligrams of sodium per day and 4,700 milligrams of potassium per day, but those 51 and older, African-Americans and those with high blood pressure, diabetes or chronic kidney disease should eat just 1,500 milligrams per day.
Foods higher in potassium are: yogurt, milk, and fruit and vegetables -- including leafy greens, grapes, blackberries, carrots and potatoes -- and citrus fruit, the researchers say.