A new study, conducted by the Center for Science in the Public Interest and Northwestern University and published in the May 13 JAMA Internal Medicine, tracked sodium content in processed food and fast food products between 2005 and 2011 and found little change.
"The voluntary approach has failed," said Stephen Havas, M.D., research professor of preventive medicine at Northwestern and an author on the paper. "The study demonstrates that the food industry has been dragging its feet and making very few changes."
"This issue will not go away unless the government steps in to protect the public. The amount of sodium in our food supply needs to be regulated."
While overall sodium content in 402 processed foods decreased by 3.5 percent, menu items at 78 fast food chains increased salt content by 2.6 percent. Moreover, while some products showed decreases of 30 percent or more, a higher number of products showed an increase of 30 percent or more.
Havas explained that, despite the health risks posed by excessive salt, food vendors have incentives not to change.
"High salt content in food benefits the food industry," Havas said. "High salt masks the flavor of ingredients that are often not the best quality and also stimulates people to drink more soda and alcohol, which the industry profits from."
According to Science Daily, excess sodium intake contributes to as many as 150,000 premature deaths in the U.S. A salt-heavy diet contributes to incidence of high blood pressure, which in turn increases risk for heart attack or stroke. The average American consumes almost two teaspoons of salt every day--about 3,400 milligrams--more than twice the recommended amount.
Havas said our tastebuds rapidly adjust to lower amounts of salt, meaning we'd hardly notice if our food got less salty.
"If it's reduced by 20 percent a year, no one would know the difference," he said.
Still, research shows there's little benefit cutting sodium intake to extreme lows. According to a panel convened by the Institute of Medicine on behalf of the Centers for Disease Control and Prevention, the effect of dropping sodium intake from 2,300 milligrams down to the recommended 1,500 has diminishing returns.
“As you go below the 2,300 mark, there is an absence of data in terms of benefit and there begin to be suggestions in subgroup populations about potential harms,” said Dr. Brian Strom, committee chairman and public health professor at the University of Pennsylvania.
In fact, too little salt can also have detrimental health effects, such as insulin resistance, sympathetic nervous system activity, and triglyceride levels, all of which can increase risk of heart disease.
For its part, the American Heart Association said it is standing firm on its recommendation of 1,500 milligrams of sodium per day, Dr. Elliott Antman, a spokesman for the AHA, told the New York Times.