People hate it when the doctors and medical reporters give them conflicting signals on what they should or shouldn’t eat. The press certainly met the public’s low expectations this week, with Healthday admonishing us that “Most Americans Should Eat Less Salt,” The New York Times reporting that there’s "No Benefit Seen in Sharp Limits on Salt in Diet,” and The New York Daily News advising us to “Go Ahead and Order that Side of Fries.” All these, remarkably, stemmed from the very same Institute of Medicine report.
Many stories quoted “experts” saying they stand by old recommendations that we should aim for no more than 1500 mg a day, but the Times actually quotes the chair of the IOM report saying that some people may suffer risks if they get less than 2,300 mg a day. Those risks include “increased rates of heart attacks and an increased risk of death.”
Oy Vey! That’s not helpful. What’s a health-conscious consumer to do?
Though some headlines mistakenly said there was a new study, the news comes from an IOM panel charged with looking into the existing science behind our current government guidelines on salt intake. The average salt intake is about 3400 mg/day. The current recommendation is for people to shoot for less than 1500 mg/day. And though 2300 is considered acceptable for people under 50 with no other risk factors, the Heart Association says we should all be under 1500.
The study’s chair, University of Pennsylvania’s Brian Strom, was widely quoted saying there’s no evidence for any benefit to going below 2300 mg and for some people, a risk of death. This is serious stuff.
Most of the stories I read consisted of he-said, she-said dueling experts. Strom for the most part represented the panel and the lack of science supporting existing guidelines. For balance, nearly everyone someone from the Center for Science in the Public Interest and the American Heart Association saying something to this effect: Oh no you don’t, there’s plenty of evidence that more than 1500 mg a day will kill you. Some stories also offered an unsurprising quote from the salt industry.
The frustrating thing about most of the stories was that the Heart Association and CSPI sources never gave specifics on this alleged evidence. Even Strom said we should watch out for “excessive” salt consumption, but nobody clarified what is supposed to be meant by excessive or whether our average consumption would qualify.
Here's Steven Reinberg at Healthday, who focused his story on the dangers of too much salt:
The heart association's sodium recommendation is "based on the strength of evidence relating excess sodium intake to high blood pressure, cardiovascular disease and stroke. We have evidence that reduced intake of sodium can prevent and treat hypertension and reduce the risk of adverse cardiovascular disease and stroke events," Antman says.
How was this evidence obtained? Who was studied? And what counted as excess?
Here’s Maggie Fox's story at NBC News:
“There is evidence to lower excessive salt intake,” Dr. Brian Strom, a professor of medicine, epidemiology and biostatistics at the University of Pennsylvania, who chaired the panel, told reporters.
There is also good evidence that lowering intake to around 2,300 milligrams a day decreased the risk of heart disease,” Strom said. But he said that the evidence was absent to support recommendations of taking it as low as 1,500 milligrams a day. And, he said, there were some studies suggesting this could harm some people — although those studies are also flawed.
Again, what’s “excessive” and how do we know any of this?
Here’s Lauren Neergaard's story from AP
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.
Frustrating! I want to know if there’s any scientific evidence that our average of 3400 mg a day is killing people. Is that what’s at stake here or is it the top 20 or 30 percent of salt consumers that are putting their lives at risk?
The New York Daily News went an inappropriately flippant story that was mostly pictures of fries and chips, with some encouragement that these foods might not be so bad after all.
At Bloomberg, Anna Edney quoted someone from the Heart Association saying the IOM missed some crucial bit of science:
The report is missing a critical component — a comprehensive review of well-established evidence which links too much sodium to high blood pressure and heart disease,” said Nancy Brown, chief executive officer of the association.
But what was this crucial piece of evidence?
The one story that dug into the science was Gina Kolata’s,which appeared on the front page of 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 once can get too little salt.
Some of the sources in these stories seem brainwashed into thinking all salt is evil and the less we consume the better.
Her story included some shockers about studies that looked directly at salt and health risks. One with a small sample of 232 heart patients showed that those who ate 2760 mg a day did better than those on 1840 mg. Another followed 28800 subjects and found higher mortality in those who consumed over 7000 mg and under 3000 mg. That's a bit worrisome.
But then she quoted AHA’s Elliott Antman saying that there’s both epidemiological evidence and studies of blood pressure to support the 1500 mg recommendation. But what are they?
None of the stories brought up news that broke in March on a link between salt consumption and autoimmune diseases such as MS. That story includes a number of very interesting researchers who are digging into the physiological effects of sodium on the human body. There’s a lot of science here that went unreported, not just on the studies but on the physiology of salt.
There’s a great story yet to be done tying all this together.