Health warnings about salt have led to it being dubbed the 'killer crystal'. But it's also a vital part of our diet, finds STEPHEN LEWIS.

TOO much salt is bad for you. The experts agree on that. Research has shown there is a connection between too much salt and hypertension, or high blood pressure. That in turn can lead to blocked arteries, kidney failure, cerebral haemorrhage and heart failure. Very unpleasant.

But salt isn't just a killer crystal: it is also a vital part of our diet. Without it we couldn't survive.

Evening Press reporter Megi Rychlikova writes vividly today of the problems she experienced after almost entirely cutting salt out of her diet. So how much salt should we take?

Like most things, it's a question of balance. Salt, as anyone who has left the top off the salt cellar knows, absorbs water. That's why we need it.

The sodium in salt helps us retain the water in our bodies that we need in order to survive.

Without salt, no matter how much water we drank it would go straight through our bodies and we'd die of dehydration.

But too much salt means we retain too much water - and that pushes our blood pressure up. Especially for those who suffer from high blood pressure anyway, that can be dangerous.

The problem is that many of us in this country eat salt without realising it.

Many processed foods - and even many everyday foods such as cheese, bacon and baked beans - are high in salt already. If we then add further salt while cooking or sprinkle it on our meals while eating, it can mean we're getting too much, says York District Hospital dietician Barbara Nachin.

Barbara says the average person should not really have more than six grams of salt a day: that's about a teaspoonful. But that is salt from all sources: not just sprinkled on your meals or added to the cooking pot.

Because of the high salt content of many processed foods, the British Heart Foundation says, the average Briton today consumes about nine grams of salt: half as much again as recommended.

"As a general rule, moderation is what we're looking for," says Barbara. "Like with fat, like with sugar, like with coffee, an excessive amount of salt is not a good idea."

Her recommendation is to use salt sparingly in your cooking if necessary - but to avoid sprinkling it on your meal afterwards. Salt alternatives - which contain potassium instead of sodium - Barbara doesn't generally recommend.

If you do suffer from low blood pressure and are worried you may not be getting enough salt, Barbara says, you should go and see your GP. They can arrange an appointment with a dietician if necessary, who will advise on your diet.

But it's unlikely, she says, that many people in the UK are not getting enough.

"In hot countries where you sweat a lot there might be a problem," she says. "But it is rare for anyone in this country to have inadequate salt."

If you are worried about your salt intake, our handy graphic will help you estimate just how much salt you are consuming every day.