Eating too much salt contributed to 2.3 million heart-related deaths worldwide in 2010, and 40 percent of those deaths were premature, researchers said.
Fifteen percent of all deaths from heart attacks, stroke and other cardiovascular disease were caused by excessive salt, and most were in lower-income countries, according to a study presented Thursday at an American Heart Association meeting in New Orleans. The United States ranked 19th of the 30 largest countries studied for deaths due to excess salt.
Excess sodium consumption is a global problem: Seventy-five percent of the world's population eats nearly twice the daily recommended amount of salt, according to a separate study of 187 countries presented at the meeting. The American Heart Association advises limiting sodium to no more than 1,500 milligrams a day.
"National and global public-health measures, such as comprehensive sodium reduction programs, could potentially save millions of lives," said Dariush Mozaffarian, one of the study's lead researchers and associate professor of medicine and epidemiology at Brigham and Women's Hospital and Harvard Medical School.
In the study linking salt and heart deaths, researchers analyzed 247 surveys on sodium consumption by adults from 1990 to 2010 and determined how the levels of salt people were eating affected cardiovascular disease risks. No more than 1,000 milligrams per day of salt was considered ideal.
Nearly 1 million of the deaths, or 40 percent of the total, happened in people who were 69 years old or younger, according to the study. Sixty percent of the deaths were in men and 40 percent were in women.
Eighty-four percent of the deaths were in low- and middle-income countries. Those with the highest death rates were Ukraine, Russia and Egypt, and the lowest were in Qatar, Kenya and United Arab Emirates.
Global sodium intake from various sources such as prepared food and soy sauce averaged nearly 4,000 milligrams a day in 2010, according to Saman Fahimi, lead author and a visiting scientist at the Harvard School of Public Health. In the U.S., the average intake was about 3,600 milligrams a day.
While the World Health Organization recommends sodium intake of fewer than 2,000 milligrams a day, 181 of 187 countries representing 99 percent of the world's population exceeded the recommended level.
Consumption of salt starts at a young age. In the U.S., nearly 75 percent of commercial pre-packaged meals and savory snacks for toddlers are high in sodium, according to additional research presented at the meeting. A product was determined to be high in sodium if it had more than 210 milligrams of salt per serving.
Some toddler meals had as much as 630 milligrams per serving, about 40 percent of the 1,500 daily limit recommended by the heart association.
"The less sodium in an infant's or toddler's diet, the less he or she may want it when older," Joyce Maalouf, lead author and fellow at the Centers for Disease Control and Prevention in Atlanta, said in a press release.