Government policies designed to reduce how much salt people eat may be cost-effective even without considering the potential healthcare savings, a recent study suggests.
That's because efforts to curb salt use through policies like public education and industry agreements would not cost that much relative to their potential to reduce mortality and disability, researchers estimate.
"We know that too much salt in the diet causes hundreds of thousands of preventable cardiovascular deaths a year," said senior study author Dr. Dariush Mozaffarian, dean of the Tufts Friedman School of Nutrition Science and Policy in Boston.
"The trillion dollar questions are how to start to bring salt down, and how much would such an effort cost," Mozaffarian added by email.
Cardiovascular diseases are the leading cause of death worldwide, killing almost one in every three people. High blood pressure is a major risk factor for cardiovascular disease in general, and heart attack and stroke in particular.
Reducing sodium intake can significantly lower blood pressure in adults, in turn helping to lower the risk of cardiovascular disease. Sodium is found not only in table salt, but in a variety of foods such as bread, milk, eggs, meat, and shellfish as well as processed items like pretzels, popcorn, soy sauce and bouillon or stock cubes.
To lower the risk of heart disease, adults should reduce sodium intake to less than 2 grams a day, or the equivalent of about one teaspoon of salt, according to the World Health Organization (WHO).
For the current study, researchers modeled the effects and costs of government-supported sodium reduction programs in 183 countries worldwide.
Researchers used data from 2010 to analyze sodium intake, blood pressure levels, the effects of sodium on blood pressure, the effects of blood pressure on cardiovascular disease, and cardiovascular disease rates.
Then, they examined costs of sodium reduction programs using a tool from the World Health Organization for examining efforts to prevent non-communicable diseases. This tool accounts for costs of things like human resources, training, meetings, supplies, equipment and mass media.
Government programs designed to achieve a 10 percent reduction in salt consumption over 10 years could save nearly 6 million life years currently lost to cardiovascular disease each year, at an average cost of $204 per life year saved, researchers report in The BMJ.
The overall effectiveness of the intervention was based on recent efforts in the UK and Turkey, which showed that such a government-supported program could reduce salt consumption by at least 10 percent over a decade.
A gradual reduction of salt intake by 10 percent over 10 years could save an average of 5.8 million disability-adjusted life years (DALY) each year that would otherwise be lost to cardiovascular disease.
Of these, about 42 percent were attributable to coronary heart disease, 40 percent to stroke and 18 percent to other types of cardiovascular disease, researchers calculated.
One limitation of the study is that researchers used raw data from 2010 covering a majority but not all of the global population, the authors note. Estimated health benefits only considered cardiovascular disease and not other medical problems that may be prevented with salt reduction, the researchers also point out.
The projected savings are conservative, however, because they don't include savings based on people who might not require treatment for heart disease due to reduced salt intake.
Even when government policies don't encourage food manufacturers to reduce sodium in processed foods, consumers can still take steps to reduce salt consumption, said Dr. Margo Denke a former professor at the University of Texas Southwestern Medical School who now works in private practice in Bandera, Texas.
"We do have and can make better choices," Denke, who wasn't involved in the study, said by email.
"We have available lower fat canned goods in many categories like canned beans and canned tomatoes that contain no sodium, lower sodium luncheon meats, lower sodium bread, lower sodium chips, lower sodium soups, and other food categories will occur once demand for these products takes off," Denke added.
"Be a label reader and vote with your grocery cart," Denke said.