How much salt is too little?

A drumbeat of studies urging Americans to consume much less sodium seemed to take a brief pause Tuesday as an independent advisory panel reported that there was no evidence for cutting back beyond the current guidelines for most people.

While critics immediately jumped on the finding as flawed, the report from the Institute of Medicine does not in fact disagree with the main message medical groups have been trying to get across for years - that most Americans take in too much salt.

"We're not saying we shouldn't be lowering excessive salt intake," said Brian Strom, a professor of public health and biostatistics at the University of Pennsylvania Perelman School of Medicine, who chaired the committee that wrote the report. But below 2,300 mg. a day, he said, "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 - nearly 50 percent more than the primary U.S. dietary guideline.

The current guidelines also say - but don't include in the condensed Nutrition Facts Label on food products - that people older than 50; African Americans; and those with high blood pressure, diabetes, or chronic kidney disease should aim for just 1,500 mg. a day. Those groups now make up more than half the population.

The Institute of Medicine, part of the National Academy of Sciences, advises the federal government on health matters, and was asked to evaluate the evidence for the lower guideline for those groups.

In general, the committee found limited evidence for lower salt levels. It also found that lower sodium levels were associated with a higher risk of adverse events in "mid- to late-stage [congestive heart failure] patients with reduced ejection fraction and who are receiving aggressive therapeutic regimens" that are not the U.S. standard of care.

It affirmed the main guideline of no more than 2,300 mg. a day.

Responding to the report, the American Heart Association said it stood by its own recommendations, that everyone consume no more than 1,500 mg. of sodium a day. Reducing salt is one key to avoiding high blood pressure that in turn leads to heart attacks and strokes, the association said.

The salt industry, in contrast, welcomed the report. "There is no scientific justification for population-wide sodium reduction to such low levels, and the recognition by the IOM experts that such low levels may cause harm may help steer overzealous organizations away from reckless recommendations," said Morton Satin, vice president, science and research, for the Salt Institute.

Numerous medical and some government organizations have been pressing the food industry to lower levels of sodium in processed and fast food, which supplies far more sodium than table salt.

The difficulty of that approach was underscored Monday by research in JAMA Internal Medicine that found sodium content in 402 processed foods declined by a mere 3.5 percent between 2005 and 2011 while it increased by 2.6 percent in 78 fast-food restaurant products.

"The average American is still in the red zone, the danger zone," said nutritionist Bonnie Liebman of the Center for Science in the Public Interest, whose colleagues wrote the JAMA article.