Workers inspect salt at the Exportadora de Sal plant in Guerrero Negro, Baja California Sur in Mexico. A recent Institute of Medicine report on sodium intake seemed to contradict the latest dietary guidelines that had been issued, leading to controversy.
Controversy has swirled around a National Academies Institute of Medicine report on sodium intake since its release, prompting health advocates, as well as some of the report’s authors, to argue that it’s been misunderstood and is in line with broader efforts encouraging Americans to consume less sodium.
A key reason the report attracted so much attention when it was issued in May was because it seemed to contradict the latest dietary guidelines, which recommend that specific groups who make up about half of the U.S. population reduce their daily sodium intake to a lower threshold than other Americans. But the report’s surprising conclusions pleased salt producers, who found fault with earlier studies. Sodium is a main ingredient in table salt.
On top of that, the report is expected to be considered by the panel formulating the 2015 dietary guidelines, which had its first meeting earlier this month.
Sen. Tom Harkin, chairman of the Health, Education, Labor and Pensions Committee, said he thinks the report has been “very misinterpreted.” And in an article published online June 6, three members of the IOM committee that produced the report agreed.
“The recent Institute of Medicine (IOM) report regarding dietary sodium has generated considerable interest and debate, as well as misinterpretation by advocates on both sides,” they wrote in The Journal of the American Medical Association.
IOM President Harvey V. Fineberg also sent a letter to Health and Human Services Secretary Kathleen Sebelius outlining what he said were the key points of the report.
The June 3 letter maintained that “some press coverage misstated” the report’s conclusions and he expressed hope that restating them “will mitigate any misunderstanding.”
The IOM is an independent, nonprofit group that provides unbiased advice as the health arm of the National Academy of Sciences.
At the center of the controversy is how much sodium should be consumed as part of an individual’s daily diet. American adults take in an average of 3,400 milligrams of sodium each day, as the IOM notes in its report.
The 2010 dietary guidelines recommend decreasing daily intake to below 2,300 milligrams, with further reductions for specific groups. People who are 51 and older, as well as individuals of any age who are African-American or have hypertension, diabetes or chronic kidney disease, are advised to reduce their consumption to 1,500 milligrams.
But the conclusions highlighted in the IOM report muddy that picture, to the concern of some health advocates but the agreement of producers.
Morton Satin, vice president of science and research for the Salt Institute, said he found the report shocking because of the IOM’s past positions and considers it to be a paradigm shift in his trade association’s favor. His group has been trying to bring this type of data to light, he said.
“There are people that are making recommendations that are not based on science,” Satin said. “They think that everything we’re saying has got to do with selling more salt. ... That’s not the issue. The issue is that we don’t want consumers being misled.”
However, Centers for Disease Control and Prevention Director Tom Frieden said that “the landscape hasn’t changed.” He noted that the CDC expects the 2015 dietary guidelines panel to consider the IOM report and additional evidence as it works on the new guidelines. His agency asked IOM to set up its sodium committee.
“The big picture is that Americans consume far too much sodium — 3,400 milligrams per day or more,” he said in a statement. “This increases blood pressure, stroke, heart attacks and early death. Reduction in daily sodium consumption would save lives and money.”
In the JAMA article, the three IOM committee members also cautioned against zeroing in on the disagreements about specific targets for sodium intake. The authors said that the IOM, American Heart Association, World Health Organization and dietary guidelines “are congruent in suggesting that excess sodium intake should be reduced, and this is likely to have significant public health effects.”
“Focusing the debate on specific targets misses the larger conclusion with which all are in agreement and may hinder implementation of important public health policy,” wrote Brian L. Strom, Cheryl A. M. Anderson and Joachim H. Ix.
Alice H. Lichtenstein, another member of the IOM committee who is also vice chairwoman of the 2015 dietary guidelines panel, echoed that sentiment in an interview.
“I think that the small aspects of the report were amplified and the general message of the whole report tended to be lost in a lot of the press coverage,” said Lichtenstein, a professor at the Tufts University Friedman School of Nutrition Science and Policy. “The committee clearly stated that the sodium intake currently is above the 2,300 [milligram] recommendation and should be reduced.”
Another thing to keep in mind, Lichtenstein noted, is that the committee’s task from the CDC was to examine sodium intake and health outcomes such as heart disease. However, some groups have expressed concern that blood pressure was not included.
In a June 6 letter to Sebelius, the CEO of the American Heart Association wrote, “It is imperative for blood pressure to be considered as an appropriate health outcome when considering national sodium policy and nutrition guidance.” CEO Nancy Brown also explained the basis for her group’s recommendation of 1,500 milligrams, which incorporates blood pressure and urged the administration to set the daily value for sodium at that level.
Satin of the Salt Institute, meanwhile, said the report’s conclusions about the 1,500-milligram level are in “total contradiction” to the AHA’s position. His concerns are about the makeup of the IOM and dietary guidelines panels rather than the recent report, and he said there’s a need for objective experts without committed opinions on sodium issues.
Both the AHA’s Brown and Michael F. Jacobson, executive director of the Center for Science in the Public Interest, said they are troubled by some of the data used by the IOM committee and by the report’s potential effect on public perceptions of sodium.
Jacobson called it “a very poorly written, misleading report” and said the confusion resulting from it could last for years; he said that doubts raised could prevent the administration from taking steps to lower sodium intake.
While most of the attention on the report has been outside Congress, Harkin and Rep. Rosa DeLauro of Connecticut said they think more research should be done on recommended sodium levels.
DeLauro, the top Democrat on the Appropriations subcommittee with jurisdiction over health, said the IOM committee repeatedly referred to research gaps. It also outlined areas for further study.
“Quite frankly, what we ought to be doing in order to be accurate and to give people the best and the most sound advice is to look at increasing the dollars that we’re doing with regard to research,” she said.
For the time being, however, the controversy over the report’s interpretations is likely to remain.
“If somebody said to me, do you think you would have anticipated that this would have happened, I would say no,” Lichtenstein said.