Cardiovascular disease describes problems with the heart and arteries that can cause heart attacks and strokes.
Although previous research has found a link between lower salt intake and reduced blood pressure, the report published on the British Medical Journal's (BMJ) website today argues that subsequent levels of cardiovascular disease in the population have been limited and inconclusive.
In the latest study, researchers analysed people who took part in two studies in the 1990s which looked at the effect that reducing salt in the diet had on blood pressure.
People taking part had high-normal blood pressure and were therefore at risk of developing cardiovascular disease. In both studies they reduced their sodium intake by approximately 25 to 35 per cent alongside a control group who did not.
Those who had cut salt for the trial tended to stick to a low-salt diet when it had finished.
The Harvard researchers found that there was a "substantial" reduction (25 per cent) in the risk of developing cardiovascular disease in this group and a 20 per cent lower mortality rate.
Commenting on the findings, Ellen Mason, cardiac nurse at the British Heart Foundation, said: "Salt intake amongst many adults and children in Britain is way too high. Salt can cause high blood pressure, which is a major risk factor for coronary heart disease - so we've all got to become detectives on the trail of this hidden killer.
"This study offers further observational evidence of strokes and heart attacks being linked to high salt intake. Many people could lower the level of salt in their diet by reducing the amount of processed food they eat. Also, by simply checking the labels and switching to a lower salt option, you'll be doing your heart a favour."
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