May 16th, 2013

Salt Report from IOM Sparks Much Heat, Only a Little Light

An Institute of Medicine report on salt earlier this week sparked a lot of controversy. The report concludes that there’s no evidence to support current efforts to lower salt consumption to less than 2300 mg/day. Unfortunately, the press coverage offered little insight into the science behind the issue. On the Knight Science Journalism Tracker blog, Faye Flam deftly uncovers the almost-universal shallow coverage in the media.

The one exception, the one story worth reading that “dug into the science,” according to Flam, is Gina Kolata’s story in the New York Times:

She tells us that the current guidelines are based only on indirect evidence which shows that salt intake has a small effect on blood pressure, and in turn blood pressure can influence risk of heart disease and stroke. From that, she wrote, “researchers created models showing how many lives could be saved if people ate less salt.” This does not fill one with confidence in the current guidelines, especially when considering the possibility that one can get too little salt.

In total contrast, Flam points to an “inappropriately flippant” story in the New York Daily News that told readers to “Go ahead, order a side of fries.”

Most of the news reports “consisted of he-said, she-said dueling experts,” writes Flam. In opposition to the IOM report, many quoted statements from the American Heart Association and the Center for Science in the Public Interest defending lower salt goals. But, she wrote, “the frustrating thing about most of the stories was that the Heart Association and CSPI sources never gave specifics on this alleged evidence.”

Flam cites serious deficiencies in stories that appeared in HealthDay, the NBC News website, AP, Bloomberg, and, of course, the Daily News story “that was mostly pictures of fries and chips, with some encouragement that these foods might not be so bad after all.”

The Times story quotes cardiologists Michael Alderman and Elliott Antman on opposing sides of the issue. Alderman, a hypertension expert who has long been skeptical of drastic sodium-lowering goals, told Kolata that “as sodium levels plunge, triglyceride levels increase, insulin resistance increases, and the activity of the sympathetic nervous system increases. Each of these factors can increase the risk of heart disease.” The IOM report, he said, “is earth-shattering. They have changed the paradigm of this issue. Until now it was all about blood pressure. Now they say it is more complicated.”

By contrast, Elliott Antman, speaking on behalf of the AHA position, told Kolata that the AHA “remained concerned about the large amount of sodium in processed foods, which makes it almost impossible for most Americans to cut back. People should aim for 1500 milligrams of sodium a day.” The AHA’s advice “is based on epidemiological data and studies that assessed the effects of sodium consumption on blood pressure,” he said.

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