The UK's leading supermarkets are preparing to support an initiative to cut the amount of salt in processed foods.

And the organisation which represents the UK's bakers has already revealed its intention to cut salt levels in bread by at least 10%.

Consensus Action on Salt and Hypertension (CASH), a campaign group, has declared Thursday "Salt Awareness Day", and the major chains are vying with each other to respond to its call for less salt content in our food.

The main source of salt in the diet is not the extra sprinkled over meals, but is already contained in bread, cereals and many other processed foods.

Processed foods are responsible for between 75% and 80% of total salt intake, said CASH.

The recommended limit is six grammes a day - but someone who believes they are eating healthily could still be consuming double that.

Someone adding extra salt to their meals consumes an average of 18.5 grammes a day, according to CASH.

High levels of salt intake have been linked primarily with high blood pressure, or hypertension, which can contribute to coronary heart disease and strokes.

Professor Graham MacGregor, CASH chairman, said that 40,000 strokes a year could be prevented if salt consumption was cut by 30%.

However, some CASH claims about the benefits of cutting everyone's salt consumption have been strongly disputed by the Salt Manufacturers' Association, who described them as "misleading and extravagant".

Supermarket strategy

Among the supermarkets which have already joined the drive to cut salt from some of their products are Asda, Marks and Spencer and the Co-op.

They are expected to be joined by others before "Salt Awareness Day".

The Federation of Bakers, which represents 80% of British bakers, has already agreed a cut of 10% with its members.

Chairman Patrick Farnsworth said: "All the nutritional advice says we should increase our consumption of bread.

"Over the past year bakers have been reviewing salt levels in bread and have come to the conclusion that consumers would like to see a further reduction in salt content."

Salt reduction campaigns are backed by the Department of Health, which has called for an official report by experts.

Consumption of high salt levels has also been linked with stomach cancer, which is one of the most common forms of the disease in the Western world.

In addition it may also be significant in osteoporosis, or the loss of bone density, which can lead to fractures later in life.