Regulations forcing food manufacturers to use lower levels of salt would in theory be far more effective for health than voluntary initiatives or dietary advice for consumers, according to new research.
High-salt diets have long been blamed for causing high blood pressure, a potential precursor for heart attacks or stroke.
Investigators in Australia looked at the country's "Tick" programme, under which food manufacturers can use a health-promotion logo on packaging if they volunteer to reduce the product's salt content to safer levels.
The team then calculated the impact on public health if the "Tick" limits were made mandatory.
They also looked at studies into the usefuless of programmes that offer salt advice to the general public and to those at high cardiovascular risk.
The team took into consideration the salt content of bread, margarine and cereals; the tonnage of product sold; the average consumption per head of those products; and the costs of drafting and enforcing legislation.
The "Tick" programme scored highly, reducing ill-health by cardiovascular disease across the Australian population by almost one percent -- more than twice as much as dietary advice -- and at a high cost-effectiveness.
But when measured in terms of the benefits on health, mandatory limits, helping to keep salt intake to below the recommended daily maximum of six grammes per day, could be far more effective, the authors suggested.
Regulations on salt would reduce cardiovascular ill health by 18 percent.
"If corporate responsibility fails, maybe there is an ethical justification for government to step in and legislate," say the authors, led by Linda Cobiac of the School of Population Health at the University of Queensland.
Laws on food content are common in many countries, requiring manufacturers for instance to add iodine to salt and folic acid in cereals.
Cardiovascular disease is the biggest cause of mortality in the world, the study said.
It claimed more than 17 million lives in 2004, a toll that could rise to more than 23 million by 2030.
The study appears in Heart, published by the British Medical Association (BMA).