May 15, 2013
Lower Sodium Intake May Not Be Healthiest Option
Lawrence LeBlond for redOrbit.com - Your Universe Online
Most studies that examine the link between sodium consumption and health outcomes support recommendations that lower sodium intake is necessary to combat serious health risks such as heart disease and stroke. However, new evidence from the Institute of Medicine (IOM) suggests that lowering sodium intake to below 2,300mg per day could also lead to adverse health effects.
On average, Americans today consume more than 3,400 mg of sodium per day, equivalent to about 1.5 teaspoons of table salt. Current dietary guidelines urge most Americans between the ages of 14 and 50 to limit sodium intake to 2,300 mg daily. For those over 50, are African Americans, or are predisposed to hypertension, diabetes, or chronic kidney disease recommendations are lowered to no more than 1,500 mg per day. The guidelines have been largely based on research that links higher sodium consumption to certain “surrogate markers” such as high blood pressure.
The new report looked at previous studies that in contrast examined how sodium consumption affects direct health outcomes like heart disease and death. They found that the studies examined support previous evidence that “reducing sodium from very high intake levels to moderate levels improves health.”
However, these studies also “suggest that lowering sodium intake too much may actually increase a person´s risk of some health problems,” noted Brian Strom, George S. Pepper Professor of Public Health and Preventive Medicine at the University of Pennsylvania (UPenn) Perelman School of Medicine.
Even as the studies they examined were limited in respect to qualitative and quantitative outcomes for sodium intake, the committee found a small number of patients with positive health outcomes pertaining to higher levels of sodium consumption.
Many studies on health outcomes are inconsistent in quality and insufficient in quantity when it comes to showing how lower sodium intake (those below 2,300 mg per day) either increases or decreases the risk of heart disease, stroke and/or mortality in the general US population. Some evidence indicates that low sodium intake may actually lead to risk of adverse health effects among those with mid- to late-stage heart failure who are receiving aggressive treatments for their condition.
They also found there is limited evidence in linking low sodium intake and health outcomes in population subgroups, such as those with diabetes, kidney disease or hypertension, or those who are over 50 years of age or are African American. And while studies on health outcomes provide some evidence for adverse health effects from low sodium intake among those with diabetes, heart disease or kidney disease, the evidence on both the benefit and harm is not strong enough to indicate subgroups should be treated any differently than the general US population, noted the report authors.
With this knowledge in hand, they said the evidence does not support recommendations that lower sodium intake within these subgroups (below 1,500 mg per day) have any positive health outcomes. The report authors said further research is needed to gain a better understanding of the associations between lower sodium intake and health outcomes, both in the general population and in the subgroups.
They acknowledged that the report does not establish a “healthy” intake range, as they were not tasked with doing so and “because variability in the methodologies used among the studies would have precluded it.”
“These studies make clear that looking at sodium´s effects on blood pressure is not enough to determine dietary sodium´s ultimate impact on health,” said Strom. “Changes in diet are more complex than simply changing a single mineral. More research is needed to understand these pathways.”
The report was sponsored by the Centers for Disease Control and Prevention (CDC).