Source: USA TODAY
Americans need to lower their excessive salt intake for their health’s sake, but it may be harmful to cut back too far, says a new report out today.
Adults in the USA consume an average of 3,400 milligrams (about 1½ teaspoons) of sodium a day, mostly from processed foods and restaurant fare.
The government’s dietary guidelines recommend that most adults reduce daily sodium intake to less than 2,300 milligrams. People who are 51 and older and those of any age who are African American or have hypertension, diabetes or chronic kidney failure are advised to further reduce intake to 1,500 milligrams a day. The American Heart Association recommends that everyone consume less than 1,500 milligrams a day.
An expert committee, convened by the Institute of Medicine, reviewed the recent research on sodium consumption’s impact on heart disease and health. The committee’s report says that evidence links excessive dietary sodium to cardiac events such as heart attacks and strokes. That was expected based on prior data on high blood pressure, a well-established marker for cardiovascular disease, stroke and cardiac-related mortality.
The report also found:
• Studies are “inconsistent and insufficient” to conclude whether lowering sodium intake below 2,300 milligrams a day either increases or decreases the risk of heart disease, stroke or death from all causes.
• Low sodium intake may have adverse health effects in those with mid- to late-stage heart failure.
• The scientific evidence doesn’t support the 1,500 milligram recommendation for people who are 51 and older and those of any age who are African American or have hypertension, diabetes or chronic kidney failure. More research is needed to explore this recommendation.
“This is a two-sided message: We endorse public health efforts to lower excessive salt intake, but we raise questions about harm from too little salt,” says IOM committee chairman Brian Strom, executive vice dean of the Perelman School of Medicine at the University of Pennsylvania.
The committee did not define “excessive” sodium or set a recommended limit for sodium, he says. Another committee will do that in a few years, he says. But eating a diet that contains only 1,500 milligrams of sodium a day is “extremely hard,” he says.
“When you look at subgroups, there are suggestions that as you go to lower dietary sodium, the health risks begin to increase, but there are methodological limitations to that research,” Strom says.
Elliott Antman, a spokesman for the American Heart Association and a professor of medicine at Harvard Medical School, says there were flaws in the studies that were reviewed by the IOM committee. Some of the research was conducted in sick patients and was not designed to study the impact of sodium intake on cardiovascular health, he says. The heart association reviewed many of the same studies and found that substantial methodological concerns limited their usefulness in setting public health recommendations, he says.
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.
In some people, sodium increases blood pressure because it holds excess fluid in the body, placing an added burden on the heart, the heart association says.
The group “is not going to change its position on sodium, and it stands with many other major health organizations,” Antman says. “We don’t want people to be distracted from the important health message that there is benefit in aggressively lowering sodium from the current levels in the American diet.”
Morton Satin, vice president of science and research for the Salt Institute, an industry group, says, “The report challenges the radical viewpoint of cutting sodium to 1,500 milligrams or below a day. This low amount has been shown to increase the health risks for some people.
“The report’s recognition that more research is needed marks a positive approach toward a more objective discussion about the complex effects of sodium reduction on overall health.”