Americans who eat a diet high in sodium and low in potassium have a 50 percent increased risk of death from any cause, and about twice the risk of death from heart attacks, according to a study published last week in the Archives of Internal Medicine. The study was conducted by researchers at the Centers for Disease Control and Prevention, Emory University and Harvard University.

This is the first study to examine the association between mortality and sodium and potassium consumption. The study analyzed data from the National Health and Nutrition Examination Survey (NHANES), a survey designed to assess the health and nutritional status of adults in the United States. Usual intake of sodium and potassium is based on dietary recall.

"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," said Elena Kuklina, M.D., Ph.D., an investigator on the study and a nutritional epidemiologist with CDC's Division for Heart Disease and Stroke Prevention. "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."

The 2010 Dietary Guidelines for Americansrecommends limiting intake of sodium to 1,500 milligrams per day for people 51 and older, African Americans, and those who have high blood pressure, diabetes, or chronic kidney disease—about half the U.S. population ages 2 and older. The dietary guidelines recommend that all other people consume less than 2,300 milligrams of sodium per day. In addition, the guidelines recommend that people choose more potassium-rich foods, advising 4,700 milligrams of potassium per day.

Sodium, primarily consumed as salt (sodium chloride), is commonly added to many processed and restaurant foods, while potassium is naturally present in many fresh foods. For example, cheese, processed meats, breads, soups, fast foods, and pastries tend to have more sodium than potassium. Yogurt, milk, fruits and vegetables tend to have less sodium and more potassium. Potassium-rich fruits and vegetables include leafy greens, such as spinach and collards, grapes, blackberries, carrots, potatoes and citrus fruits such as oranges and grapefruit.

In general, people who reduce their sodium consumption, increase their potassium consumption, or do both, benefit from improved blood pressure and reduce their risk for developing other serious health problems. Adults can improve their health by knowing recommended limits for daily sodium intake, choosing foods like fresh or frozen fruits and vegetables, and unprocessed or minimally processed fish, meat or poultry, low-fat milk or plain yogurt, asking for foods with no or low salt at restaurants, and reading the nutrition labels of foods before purchasing can improve health for all adults.