Questions have been raised about the effect of sodium on the heart in a new European population study coordinated in Belgium and appearing in yesterday’s Journal of the American Medical Association.
The study involved following 3,681 individuals, with an average age of 40, for approximately eight years. The researchers tested the subjects’ sodium excretion in the urine and found that systolic blood pressure was a little lower in those who excreted less sodium, however, this did not decrease the likelihood of cardiovascular death — as a matter of fact, people with lower sodium excretion were more likely to experience cardiovascular death. Similar results were obtained in subjects younger and older than 60 years.
“Lower sodium intake is recommended for people with high blood pressure and people with heart failure, but recommending it to the population as a whole, I wouldn’t do without proving it’s completely safe,” says Jan Staessen, a professor of medicine at the University of Leuven, Belgium, and one of the study authors.
“If one lowers sodium intake to lower blood pressure, this change in sodium activates several systems (including the renin-angiotensin aldosterone system) that conserve sodium, and those systems are implicated in disease processes such as damaging the arterial wall and kidneys,” according to him.
This study may be applicable to Americans of white European descent, but it might be less applicable to blacks as they are considered more salt sensitive, says Staessen.
The study is already attracting criticism from medical experts here. According to Ralph Sacco, president of the American Heart Association and chairman of neurology at the University of Miami, this is just one study involving relatively young, mostly white population and blood pressure has a tendency to increase with age and affect African-Americans disproportionately.
“We have based our recommendations on the many scientific studies which show a strong relationship between reduced sodium consumption and a lower risk of heart attacks, congestive heart failure and stroke,” he states. “There are good randomized, controlled studies the gold standard of scientific studies that show a lower sodium diet has a meaningful effect on blood pressure.”
Gina Lundberg, a preventive cardiologist in Atlanta, is in support of the 1,500-milligram guideline. “We’re all eating too much sodium because we eat too many prepared, processed foods,” she says.