High Sodium Levels Protect Healthy Hearts, European Study Suggests
By Daniel J. DeNoon
WebMD Health News
Reviewed by Laura J. Martin, MD
May 4, 2011 - A high salt diet isn't bad for you, it's good for healthy people, European researchers suggest.
Jan A. Staessen, MD, PhD, of the University of Leuven, Belgium, led a study that measured urinary sodium levels in 3,681 healthy, 40-ish people and then followed their health for about eight years.
Their finding: People with the highest sodium levels had a significantly lower risk of dying from heart disease than did people with the lowest sodium levels.
"Our current findings refute the estimates of computer models of lives saved and health care costs reduced with lower salt intake," Staessen and colleagues conclude in the Journal of the American Medical Association. "They do also not support the current recommendations of a generalized and indiscriminate reduction of salt intake at the population level."
These recommendations come from the American Heart Association (AHA), which advises everyone to limit their sodium intake to 1,500 milligrams of sodium per day -- a substantial cut from the 3,600 to 4,800 milligrams of sodium most Americans get each day.
Predictably, those guidelines -- and the slightly less stringent official U.S. salt guidelines -- drew fire from the Salt Institute, the trade group representing the salt industry. The group has been quick to herald the European findings.
"We now know conclusively that the U.S. government's war on salt consumption will cause harm," Lori Roman, president of the Salt Institute, says in a news release. "This study confirms previous research indicating that reductions in sodium lead to an increased risk of disease and death."
Nothing could be further from the truth, says Ralph L. Sacco, MD, president of the American Heart Association and chairman of the neurology department at the University of Miami Miller School of Medicine.
"We need to take this article with a large grain of salt," Sacco tells WebMD. "There are major problems with it, and there is only this one article with these findings, which are contrary findings to what we and others have found."
Sacco notes that the study looks only at relatively young, white Europeans, with no sign of high blood pressure or heart disease, over a relatively short period of time. He suggests that the measure on which the study is based -- collection of all urine output over a 24-hour period -- is subject to large variation if even one sample is missed during the collection period.
More to the point, Sacco notes a long string of studies linking high salt intake to high blood pressure, heart disease, and stroke.
"The AHA recommendation to reduce salt intake is based on strong science, not just extrapolations or complex math," Sacco says. "There have even been randomized trials, the strongest evidence we have that show people who follow lower-sodium diets have lower blood pressure and fewer heart attacks and strokes."
Staessen and colleagues note that blood pressure did go up a bit in people with the highest sodium levels. They agree that people with high blood pressure can lower their blood pressure by lowering their salt intake. But they suggest that previous studies have overestimated the effects of salt intake on healthy people who are not oversensitive to sodium.
Moreover, they point to studies showing that people have a very difficult time lowering their salt intake. This, they suggest, shows that the body actually fights against lowering salt intake and regulates itself to keep sodium levels "within a narrow range."