Sodium-Potassium Ratio Linked to Heart-Disease Risk


If you're worried about hypertension, a new study warns that the more sodium from salt in your diet and the less potassium, the greater your risk for heart disease. For people with prehypertension, researchers found that every one-unit increase in the ratio of sodium to potassium excretion was associated with a 24% increase in risk of cardiovascular disease.

Previous research has established separately that higher sodium and lower potassium intake both appear associated with high blood pressure, a known risk factor for cardiovascular disease.

Combining these factors, researchers led by Nancy R. Cook, ScD, of Brigham and Women's Hospital and Harvard Medical School looked at data from two Trials of Hypertension Prevention studies on a total of 2,275 pre-hypertensive subjects, ages 30 to 54. They used tests of the amounts of sodium and potassium excreted in subjects' urine to gauge intakes of both chemical elements. Over the course of the two parts of the study, subjects suffered 193 cardiovascular events, such as a heart attack, stroke or cardiovascular death.

When either sodium or potassium excretion was analyzed separately, no significant difference in cardiovascular risk was observed. But when Cook and colleagues looked at the ratio of sodium to potassium, a significant trend emerged: Risk for cardiovascular events overall, as well as for coronary heart disease and stroke specifically, increased as the sodiumpotassium ratio rose.

"The sodium to potassium excretion ratio displayed the strongest and statistically significant association," the researchers concluded, writing in Archives of Internal Medicine. "The totality of evidence suggests that lowering dietary sodium intake, while increasing potassium consumption, at the population level might reduce the incidence of cardiovascular disease."

The average American consumes about 3.6 grams of sodium daily, much of it in the form of salt in processed, packaged or restaurant foods. The current federal Dietary Guidelines for Americans recommend a sodium intake of less than 2.3 grams per day (about the amount in one teaspoon of salt), while the American Heart Association advises those with heart disease to aim for under 2 grams daily.

But many Americans don't get enough potassium. The dietary guidelines recommend 4.7 grams of potassium per day, which is about the amount found in 10 bananas. Levels of potassium in the US diet actually dropped almost 10% from 1945 to 2000, to a per capita intake of 3.74 grams.

TO LEARN MORE: Archives of Internal Medicine, Jan. 12, 009; abstract at .

Did you know… An Advertising Age survey finds that 60% of Americans have scaled back on expensive-and often high-calorie-coffee drinks within the past six months.

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