We are a people who love our salt; and with good reason. It’s a chemical essential for health, maintaining the body’s electrolyte balance and playing a key role in the function of bodily fluids. Our hankering for salt comes naturally, but as is often our nature, we have a hard time knowing when we’ve had enough.
Over the past several decades there has been much ado about reducing our sodium because of its link to cardiovascular disease; the current Dietary Guidelines for Americans urge people from 14 to 50 to limit their sodium intake to 2,300 mg daily. Those 51 or older, African Americans, and people with hypertension, diabetes, or chronic kidney disease are advised to limit sodium to 1,500 mg per day.
Yet the average American still consumes 3,400 mg or more of sodium a day, which is about one and a half teaspoons of salt.
We are also a people who love our health studies, and there has been no shortage of scientific reports on the links between sodium consumption and health outcomes. And as the case always seems to be, most of them seem to disagree with each other.
With that in mind, the Centers for Disease Control and Prevention (CDC) sponsored a report by the Institute of Medicine (IOM) to review a roster of recent research. The IOM was asked to “examine the designs, methodologies, and conclusions in this latest body of research on dietary sodium intake and health outcomes.” The committee was also asked to comment on the implications of their findings, according to the Report Brief.
The committee found that the studies were inconsistent in their methodological approaches to measuring sodium intake and that there were many limitations related to “the quality of those measures and the quantity of available evidence assessing sodium intake and health outcomes.” Specifically, the committee cited over- or underreporting intake levels and incomplete collection of samples.
That said, there was enough for the IOM to make some important conclusions.
“These new studies support previous findings that reducing sodium from very high intake levels to moderate levels improves health,” said committee chair Brian Strom, George S. Pepper Professor of Public Health and Preventive Medicine at the University of Pennsylvania Perelman School of Medicine.
“But they also suggest that lowering sodium intake too much may actually increase a person’s risk of some health problems,” he added in the IOM press release, particularly the risk of adverse health effects among those with mid- to late-stage heart failure who are receiving aggressive treatment for their disease.
The new report notes that that the “studies on health outcomes are inconsistent in quality and insufficient in quantity to conclude that lowering sodium intake levels below 2,300 mg/day either increases or decreases the risk of heart disease, stroke, or all-cause mortality in the general U.S. population.”
In addition, they found some evidence for adverse health effects of low sodium intake (in ranges approximating 1,500 to 2,300 mg daily) among those with diabetes, kidney disease, or heart disease.
“The evidence on both the benefit and harm is not strong enough to indicate that these subgroups should be treated differently from the general U.S. population. Thus, the evidence on direct health outcomes does not support recommendations to lower sodium intake within these subgroups to or even below 1,500 mg daily,” the study says.
Unfortunately for those of us who just want some firm numbers to stick to, the report does not establish a “healthy” intake range, as the committee was not tasked with doing so. Until further notice, the best approach seems to be: enough, but not too much.
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