The government watchdog the Food Standards Agency has announced targets for reducing salt in a range of food products.

The move is designed to cut average daily salt intake in the diet, as too much salt is linked to high blood pressure, which in turn can increase the risk of heart attacks and strokes.

Why do we need salt?

Salt is a commonly occuring mineral, the technical name of which is sodium chloride. It is the sodium part of salt that is important. The body needs a certain amount of sodium to function properly.

Sodium helps to maintain the concentration of body fluids at correct levels. It also plays a central role in the transmission of electrical impulses in the nerves, and helps cells to take up nutrients.

Why is too much salt bad?

In adults, when levels of sodium are too high, the body retains too much water and the volume of bodily fluids increases.

Many scientists, although not all, believe this process is linked to high blood pressure, or hypertension, which in turn is linked to a greater risk of coronary heart disease and stroke.

With high levels of fluid circulating through the brain there is a greater chance that weaknesses in the brain's blood vessels are exposed, and that they may burst, causing a stroke.

Similarly, a greater volume of fluid passing through the heart can place additional strain on the organ, increasing the possibility of coronary disease.

However, there are many potential causes of hypertension and coronary heart disease, and some scientists deny that salt plays any significant role at all.

An adult will be able to remove salt from the body through the kidneys into the urine.

However, very young babies do not have the capacity to process large quantities of salt as the kidneys are not yet developed.

If they are given adult food with a higher salt content before they are at least four months old, excess sodium can accumulate in the body, causing kidney, liver and brain damage, and in very occasional cases, death.

It is recommended that babies are given only milk, whether breast or formula, for the first four months of life.

Baby foods are supposed to contain lower levels of salt, and it is recommended that if adult foods are to be given, unprocessed foods should be used, and no salt added.

How much salt should we eat?

The government recommends that adults should eat 6g of salt a day. However, the average intake of salt is between 9g and 10g a day.

Experts estimate that if average consumption was cut to 6g a day it would prevent 70,000 heart attacks and strokes a year.

The main sources of salt in the diet are processed foods and salt added during cooking or at the table. Meat and meat products, and bread can also be high in salt.

Processed foods are thought to account for around 75% of the average person's salt intake.

However, research published in The Lancet medical journal suggested that most people could not tell the difference between loaves with markedly different salt content.

Salt is added to processed foods to aid preservation and to improve taste. Sodium is present in additives such as monosodium glutamate and sodium bicarbonate.

Small amounts of sodium can be found naturally in some foods such as eggs and fish.

The salt we sprinkle on our food from cellar accounts for only 10%-15% of our intake.

What is the Food Standards Agency doing?

It has drawn up targets for the food industry to cut the salt content of a range of 85 products.

The aim is that if the targets were enforced, the average daily intake of salt would fall to the recommended level of 6g.

However, the targets are voluntary, and campaigners say they have not been set at a sufficiently tough level. They argue that even if followed by the food industry they would result in an average daily intake of 8g, rather than 6g.

Professor Graham MacGregor, of Cash (Consensus Action on Salt and Health), said that would mean an extra 30,000 more strokes and heart attacks a year in the UK - 15,000 of which would be fatal.

What should we do?

Dr Wynnie Chan, a nutrition scientist for the British Nurtrition Foundation, says that everybody should look to reduce the amount of salt in their diet.

"It would have a significant effect on those people who need to reduce their salt levels because they are susceptible to hypertension, but it would also do no harm for the whole population to reduce its salt intake," she said.

Dr Chan said there were four main ways to reduce salt intake: