A new study has found that a moderate decrease in daily salt intake could benefit and reduce the rates of heart disease and deaths.

Researchers at the American Heart Association's 49th Annual Conference on Cardiovascular Disease Epidemiology and Prevention said that for every gram of salt that is reduced in the diets daily, fewer new heart disease cases and fewer deaths would occur over a decade.

''A very modest decrease in the amount of salt - hardly detectable in the taste of food - can have dramatic health,'' said Kirsten Bibbins-Domingo, Ph.D., M.D., M.A.S., 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 modeling.''

A 3-gram–a-day reduction in salt intake (about 1,200 mg of sodium) would result in 6 per cent fewer cases of new heart disease, 8 per cent fewer heart attacks, and 3 per cent fewer deaths.

For years, ample evidence has linked salt intake to high blood pressure and heart disease. Yet, salt consumption has risen by 50 per cent and blood pressure has risen by nearly the same amount since the 1970s, according to researchers.

Currently, Americans eat 9-12 grams of salt per day (or 3600-4800 mg of sodium). This amount is far in excess than recommended by most health organisations (5-6 grams / day of salt or 2000-2400 mg sodium). Each gram of salt contains 0.4 grams of sodium.

''It's clear that we need to lower salt intake, but individuals find it hard to make substantial cuts because most salt comes from processed foods, not from the salt shaker,'' Bibbins-Domingo said. ''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.''

To estimate the benefit of making small reductions in salt intake, the investigators used the Coronary Heart Disease Policy Model, a computer simulation of heart disease in the US adult population.

The researchers used the model to estimate the impact of an immediate reduction of daily salt intake by 0–6 grams on the incidence of cardiovascular disease and deaths between 2010–2019. In that period, the model suggests that more than 800,000 life-years could be saved for each gram of salt lowered.

Larger reductions would have greater benefits, with a 6 gram reduction resulting in 1.4 million fewer heart disease cases, 1.1 million fewer deaths and over 4 million life-years saved.

Because the majority of salt in the diet comes from prepared and packaged foods, the results of the study reveal the need for regulatory changes or voluntary actions by the food industry to make achievable changes in heart health, Bibbins-Domingo said.

The researchers are planning to assess the cost-effectiveness of various interventions already being used to reduce salt consumption in other countries, including industry collaborations, regulations and labeling changes.