As many as a half a million American lives could be saved if they all ate a fraction of a teaspoon of salt less every day, according to a new study.

The study found that a gradual decrease in salt consumption over a decade - ending in a 40% reduction - would prolong the lives of between 2.8 lakh and five lakh people respectively by decreasing the risk of hypertension and heart disease.

"It confirms the enormous potential value in reducing the consumption of sodium," Michael Jacobson, executive director of the consumer watchdog Center for Science in the Public Interest, said.

The study is novel in that three groups of researchers using different methods all came to the same conclusion, he said.

Americans ingest, on average, 3,600mg of sodium daily, compared with 1,500 recommended by The Centers for Disease Control and Prevention. The study looked at cutting everyone's salt intake down to 2,200mg.