WASHINGTON -- A surprising new report questions public health efforts to get Americans to cut back sharply on salt, saying it's not clear whether eating super-low levels is worth the struggle.
Make no mistake: Most Americans eat way too much salt, not just from salt shakers but because of sodium hidden inside processed foods and restaurant meals. Tuesday's report stresses that, overall, the nation needs to ease back on the sodium for better heart health.
But there's no good evidence that eating very low levels -- below the 2,300 milligrams a day that the government recommends for most people -- offers benefits, even though national guidelines urge that certain high-risk patients do just that, the Institute of Medicine concluded.
Also, there were hints, albeit from studies with serious flaws, that eating the lowest levels might actually harm people being aggressively treated for serious heart failure, the report added. The group, which advises the government about health, urged more and better research to settle the best target range.
"We're not saying we shouldn't be lowering excessive salt intake," said biochemist Brian Strom, executive vice dean for institutional affairs at the University of Pennsylvania's Perelman School of Medicine, who led the institute's committee. But below 2,300 mg a day, "there is simply a lack of data that shows it is beneficial."
The average American consumes more than 3,400 mg of sodium a day, equivalent to 1 1/2 teaspoons. Current U.S. dietary guidelines say most people should limit that to 2,300 mg a day, while certain people -- those older than 50, African-Americans, and people with high blood pressure, diabetes or chronic kidney disease -- should aim for just 1,500 mg.
Tuesday's report sparked an immediate outcry from health organizations that long have battled to lower the nation's salt consumption. The American Heart Association said it stood by its own recommendations -- stricter than the government's -- that everyone eat no more than 1,500 mg of sodium a day.
The IOM committee was asked to examine whether eating less salt directly affects longer-term outcomes, such as heart attacks and death. That is harder to prove, especially since the panel stressed that many studies it reviewed had quality problems. Among those, said cardiologist Elliott Antman at Boston's Brigham and Women's Hospital, a heart association spokesman, was including some patients too sick for diet to matter.
Debating how little salt is too little is a moot point, added nutritionist Bonnie Liebman of the Center for Science in the Public Interest. "The average American is still in the red zone, the danger zone," she said.
Some salt is necessary for good health, although it is unclear exactly how much. But today, it's very hard to cut back to 1,500 mg unless you always cook from scratch, or eat too little food in general because of illness, Ms. Liebman said.