New research questions the link between sodium consumption and health problems, but the American Heart Association reiterated Wednesday that the connection is well established and urged Americans to continue to lower the salt in their diets.
A report published in the American Journal of Hypertension analyzed 25 existing studies on sodium intake and found that people who consume between 2,645 and 4,945 milligrams a day had fewer health problems than those either above or below that range. That’s well above the American Heart Association recommendation of 1,500 milligrams or less. The average American has about 3,400 milligrams a day.
However, the new study relied on flawed data and should not change the way anyone looks at sodium, according to the American Heart Association.
“There is a significant body of scientific research that reinforces a very dangerous association between sodium intake and significant health problems, including in some cases death,” American Heart Association CEO Nancy Brown said. “I wish we could say sodium intake does not matter that much to your health, but it does. Millions of Americans consume too much sodium and as a result face an increased risk for high blood pressure, stroke and other very serious conditions. Based on decades of scientifically sound research, we simply cannot minimize the impact of excess sodium in our diet.”
Heart disease and stroke are the two leading causes of death in the world, and high blood pressure contributes to both. In some people, sodium increases blood pressure because it holds excess fluid in the body, creating an added burden on the heart. Too much salt adversely affects the heart, kidneys and blood vessels. Ninety percent of all American adults are expected to develop high blood pressure in their lifetime.
Recent evidence shows high blood pressure is to blame for 35 percent of heart attack and stroke events, 49 percent of heart failure episodes and 24 percent of premature deaths.
The new research adds to a larger discussion that has evolved over the last few years about appropriate levels of salt intake and its impact.
Niels Graudal, the latest study’s lead author, said the results are an important extension of the findings of a 2013 Institute of Medicine report that concluded there is not enough evidence to show that sodium reduction below 2,300 milligrams daily leads to less heart disease, stroke and reduced risk of death.
However, those studies were poorly designed to examine the relationship between sodium intake and mortality, and the findings fail to take into account well-established evidence about sodium intake, the American Heart Association said. Other problems with the new study included unreliable measurements of sodium intake and an overemphasis on studying sick people rather than the general population.
Lawrence Appel, M.D., MPH, director of the Welch Center for Prevention, Epidemiology and Clinical Research and Johns Hopkins University and a volunteer with the American Heart Association, stressed the importance of sodium reduction in preventing heart disease and stroke.
“The bottom line is to prevent cardiovascular disease and improve cardiovascular health, we have to improve blood pressure control,” said Appel, who has been a member of the associaton’s Nutrition Committee for more than 10 years. “Lowering sodium intake is key to achieving this goal, along with improving overall diet, controlling weight and increasing physical activity.”
The problem with this kind of debate is that it creates doubt, Appel said, and that doubt keeps individuals and companies from working to reduce salt in packaged, processed and restaurant food, from which Americans get three-fourths of their sodium intake.
“Debates among scientists are common, yet should not derail sound policy,” he said. “In this case, major organizations such as the American Heart Association and the World Hypertension League, remain convinced — excess sodium intake is a major public health problem. Now is the time for action, not hesitation.”