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Sodium/Potassium Ratio Linked to Cardiovascular Disease Risk

Two nutrients, sodium and potassium, likely work together to affect blood pressure and heart disease risk, according to a new study.

Nearly 1 in 3 adult Americans has high blood pressure—defined as 140/90 mmHg or higher—and about 37% have pre-hypertension, which is defined as 120-139/80-89 mmHg. High blood pressure is dangerous because it makes the heart work too hard and increases the risk of cardiovascular diseases like heart disease and stroke, the first- and third-leading causes of death nationwide.

In the past, researchers funded by NIH’s National Heart, Lung and Blood Institute (NHLBI) showed that long-term interventions to reduce sodium intake in people with prehypertension can lower blood pressure and reduce the risk of cardiovascular disease.

The new Trials of Hypertension Prevention Follow-up Study involved almost 3,000 participants who were 30 to 54 years old and had prehypertension. Researchers collected urine intermittently during 24-hour periods over 18 months in one trial and 36 months in another. They then compared the urinary levels of sodium and potassium with subsequent cardiovascular diseases during 10 to 15 years of follow-up.

The results, published in the January 12, 2009, issue of the Archives of Internal Medicine, showed a significant increase in the risk of cardiovascular disease with higher ratios of sodium to potassium. A high sodium/potassium ratio was a stronger indicator of increased risk among the participants in the study than levels of either sodium or potassium alone.

These results support previous findings that lowering dietary sodium intake while increasing potassium intake can reduce the incidence of cardiovascular disease. “This means that the general population should eat foods low in sodium and high in potassium,” says Dr. Eva Obarzanek of NHLBI’s Division of Prevention and Population Studies, one of the study’s co-authors.

Recent national nutrition surveys show that, on average, Americans consume about 3300 mg of sodium per day (almost 1-1/2 tsp per day of salt) and 2600 mg potassium per day. These are far from the recommended goals of 2300 mg or less for sodium and 4700 mg or more for potassium. In fact, a recent report found that only 13% of the population is meeting the sodium goal and well below 5% is meeting the potassium goal.

“First and foremost, people need to read nutrition labels on foods and choose foods that are low in sodium,” Obarzanek says. “People can get accustomed to a lower sodium level if they persist in consuming a diet low in sodium. Over time, the taste and preference for salt decreases.”

You can boost your potassium intake by choosing more whole unprocessed foods: fruits, vegetables, whole grains, fresh or frozen meat, poultry and fish, and low-fat or non-fat milk products.  These foods tend to be low in sodium as well.