High salt + low potassium = early death: study
CHICAGO - Put down the salt shakers. Eating too much salt and too little potassium can increase the risk of death, US government researchers said on Monday.
The findings from a team at the US Centers for Disease Control and Prevention are a counterpoint to a fiercely-debated study released last week that found no evidence that making small cuts in salt intake lowers the risk of heart disease and premature death.
"Salt is still bad for you," said Dr. Thomas Farley, Health Commissioner for New York City, which is leading a campaign to reduce salt in restaurant and packaged foods by 25% over five years.
Most health experts agree with Farley that consuming too much salt is not good for you and that cutting salt intake can reduce high blood pressure, which raises the risk of heart attack and stroke. Salt intake has been rising since the 1970s, with Americans consuming about twice the recommended daily limit.
The CDC study, published in the Archives of Internal Medicine, specifically focused on growing research that shows a diet high in salt and low in potassium is especially risky.
Farley, who wrote an editorial on the CDC study, said it is one of the best yet looking at the long-term effects of eating too much salt.
"It is entirely consistent with what we've said all along about sodium intake," Farley said in a telephone interview.
For the study, researchers looked at the long-term effects of sodium and potassium intake as part of a 15-year study of more than 12,000 people.
By the end of the study period, 2,270 of the study participants had died; 825 of these deaths were from heart disease and 433 were from blood clots and strokes.
Potassium is key
They found that people who had a high salt intake and a low potassium intake were most at risk.
"People who ate a diet high in sodium and low in potassium had a 50% increased risk of death from any cause, and about twice the risk of death -- or a 200% increase -- from a heart attack," said Dr. Elena Kuklina of the CDC who helped lead the study.
She said consumers need to increase the levels of potassium in their diet by adding more servings of fresh fruits and vegetables, such as spinach, grapes, carrots, sweet potatoes, and low fat milk and yogurt.
The Salt Institute, an industry group, challenged the findings, pointing out that the CDC study found that the link between salt intake and heart disease was statistically insignificant.
"This is a highly flawed publication that reveals more about the anti-salt agenda being pursued by the CDC than about any relationship between salt and health," said Mort Satin, the Salt Institute's Director of Science and Research.
"The only significance is between low potassium and mortality," Satin said in a statement.
Dr. Robert Briss, director of the National Center for Chronic Disease Prevention and Health Promotion at the CDC, said the findings support the general weight of evidence and suggests that higher doses of sodium are linked with poor health consequences.
And it suggests "that higher potassium may be better for you," Briss said in a telephone interview.
"About 90% of Americans consume more sodium than is recommended. This impacts their blood pressure," Briss said.
"Most of that sodium is not related to the salt shaker but it is in foods and especially processed and restaurant foods that we buy and order from restaurants. Consumers, even motivated ones, don't have as much choice as they could," he said.
Kuklina said potassium often counteracts the effects of salt in the diet. This equilibrium is affected when people eat highly processed foods, which tend to increase sodium levels and decrease potassium content.
"If sodium increases your high blood pressure, potassium decreases it. If sodium retains water, potassium helps you get rid of it," she said.
Instead of focusing only on salt, Kuklina said researchers should focus on the balance between potassium and salt.
"We need to strive to do both -- decrease your sodium intake and increase your potassium intake," she said.