High sodium intake contributes to high blood pressure the leading risk factor for death from strokes and heart disease. (Larry Crowe, Associated Press)

For every gram of salt that Americans cut from their diets every day, there would be 200,000 fewer deaths over a decade, researchers said Wednesday.

"A very modest decrease in the amount of salt — hardly detectable in the taste of food — can have dramatic health benefits for the U.S.," said Dr. Kirsten Bibbins-Domingo, lead author of the study and an assistant professor of medicine and of epidemiology at the University of California, San Francisco.

"It was a surprise to see the magnitude of the impact on the population, given the very small reductions in salt that we were modelling."

The findings were presented on Wednesday at the American Heart Association's annual conference on cardiovascular disease epidemiology and prevention in Palm Harbor, Fla.

The researchers based their results from a validated computer model of heart disease among U.S. adults.

They estimated that cutting daily salt intake by three grams, or 1,200 milligrams of sodium, would result in:

• Six per cent fewer cases of new heart disease.
• Eight per cent fewer heart attacks.
• Three per cent fewer deaths.

75% of sodium from processed foods

The majority of dietary salt comes from prepared and packaged foods.

"Our study suggests that the food industry and those who regulate it could contribute substantially to the health of the nation by achieving even small reductions in the amount of salt in these processed foods," Bibbins-Domingo said.

In 2007, researchers in British Columbia estimated that cutting Canadians' salt intake in half would eliminate high blood pressure in one million people and save the health-care systems hundreds of millions of dollars annually.

About one-third of people are sensitive to the sodium in salt, the Heart and Stroke Foundation of Canada's website says. When these people eat too much salt, it can raise their blood pressure and increase the risk of heart disease and stroke.

A quarter of adults, about five million Canadians, have hypertension, a major risk factor for stroke and heart attack. Hypertension also contributes to kidney failure and dementia, according to the World Health Organization.

In total, the national Canadian average for daily sodium intake registered at 3,092 milligrams, one-third more than the recommended limit, Statistics Canada reported in 2007. That does not include salt people add to their food.

The Heart and Stroke Foundation suggests Canadian adults consume no more than five millilitres of salt — about one teaspoon — or 2,300 milligrams of sodium per day.

Americans consume up to 75 per cent of their sodium from processed foods like tomato sauce, soups, condiments, canned foods and prepared mixes, according to the American Heart Association.

The study was funded by the University of California, San Francisco.