Slashing salt intake by just 3 grams a day -- the equivalent of half a teaspoon -- could dramatically cut the incidence of heart disease and death in U.S. adults.
According to the authors of a study in the Jan. 20 online edition of the New England Journal of Medicine, the projected reductions would be similar to the benefits accruing from a 50 percent drop in the smoking rate and a 5 percent decline in body mass index among obese adults.
"There's no question that Americans eat too much salt," said Dr. Robert Eckel, a professor of medicine at the University of Colorado Denver School of Medicine. "The idea of salt restriction and reducing blood pressure-related outcomes such as heart disease and stroke has been under consideration for some time. This group just simply took a map to it. The study certainly has scientific validity in terms of the importance of salt reduction for quality of life and longevity."
"Is everyone going to make the same change? Maybe not," said Karen Congro, director of the Wellness for Life Program at Brooklyn Hospital Center in New York City. "But even a small change would reduce the total number of strokes and heart attacks over time because the situation is so dire. It would also be beneficial to immediate health."
U.S. health agencies recommend that most adults limit their daily consumption of salt to less than 5.8 grams (2,300 milligrams [mg] of sodium), with 3.7 grams a day preferable.
The American Heart Association urges the average American to eat less than 2,300 mg of sodium daily, but also notes that older people, blacks and people with high blood pressure need to go even lower -- to under 1,500 mg per day.
Despite these recommendations, the average daily intake of salt is on the increase.
In 2005-2006, the study authors stated, men in the United States took in an average of 10.4 grams of salt a day and women consumed 7.3 grams a day, far more than the suggested limit.
Excess salt can cause or worsen high blood pressure and raises the risk for cardiovascular disease.
This is not the first time Americans' favorite dietary supplement has hit the news in recent days.
The New York City Health Department, under Mayor Michael Bloomberg, has announced that it is spearheading the "National Salt Reduction Initiative," which aims for a 20 percent reduction in salt consumption over five years.
The initiative is targeted primarily at restaurants and food manufacturers, which supply the gross majority of sodium in American diets.
Only about one-quarter of the salt in the U.S. diet comes directly from the kitchen table salt shaker.
The researchers, from the University of California, San Francisco, fed previously published data on heart disease in U.S. adults aged 35 to 84 into a computer model.
The model then predicted that the reduction of 3 grams of salt a day would cut the number of new cases of coronary heart disease each year by 60,000 to 120,000; stroke by 32,000 to 66,000 cases; and heart attacks by 54,000 to 99,000.
The annual number of deaths from any cause would be reduced by 44,000 to 92,000.
Limiting salt intake would be good for the fiscal diet as well, saving an estimated $10 billion to $24 billion in health care costs yearly, the paper found.
But if Americans cut even a mere 1 gram of salt from their meals and snacks every day, the effects would still be stunning, the authors stated: 20,000 to 40,000 fewer cases of coronary heart disease; 18,000 to 35,000 fewer heart attacks; 11,000 to 23,000 fewer strokes; and 15,000 to 32,000 fewer deaths.
Given that so much sodium comes from processed food, the authors urged a public health initiative to curb consumption.