Salt health risks tied to potassium deficiency

By Deborah Kotz, Globe Staff

Contradictory studies on salt risks have been trickling out over the past few months -- making it tough to determine just how much healthy people need to worry about sodium intake. Some find that eating too much salt takes years off your life, while others find that it doesn’t. Perhaps it’s just easiest to take all the findings with a (no pun intended) grain of salt.

Or perhaps the nutritional puzzle is a bit more complex. Another finding this week published in the Archives of Internal Medicine suggests that it’s not just the amount of sodium we eat but how much we eat in relation to the amount of potassium that determines whether we have an increased risk of dying from heart disease and other causes.

The research, which surveyed the dietary habits of more than 12,000 US adults, found that those who had the greatest sodium to potassium ratio (eating more sodium and less potassium) had a 50 percent higher risk of dying from any cause and more than twice the likelihood of dying from heart attacks over 15 years compared with those who had the smallest ratio, eating less sodium and more potassium.

When considered independently, neither sodium nor potassium contributed as much to health problems as when they were combined in a ratio.

“This may be due to complex interactions between potassium and sodium at cellular levels,” write the researchers from the federal Centers for Disease Control and Prevention, Harvard School of Public Health, and Emory University. Potassium may counteract sodium’s blood-pressure-raising effect of narrowing arteries by triggering the release of a chemical that widens arteries.

“The study’s findings are particularly troubling because US 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, one of the CDC researchers, said in a statement. We also don’t consume enough potassium; we’re supposed to get 4,700 mg per day, which usually requires us to eat about five to seven servings a day of fruit (bananas, citrus fruits, and raisins), vegetables (leafy greens, potatoes), and beans.

Clearly the take-home message of the study is to eat fewer high-salt processed foods and more fruits and veggies to improve that sodium-potassium ratio and your overall health in general -- regardless of whether salt on its own is the villain.