Feed children salty food and you condemn them to high blood pressure in later life. That’s the stark message from a group of medical specialists who are campaigning for greater awareness about the harmful effects of a high-salt diet.

Salt causes the body to retain more fluid, and is thought to increase blood volume over time, the main cause of hypertension. According to Consensus Action on Salt and Health (Cash), scientific evidence suggests that adults should consume no more than 6 grams, or a teaspoonful, of salt per day (our bodies only need around 4 grams). For children aged seven to 14, the target intake drops to 5 grams, while children aged one to six should have no more than 2 grams (babies should have no added salt at all).

However, recent surveys have shown not only that adults are consuming between 10 and 12 grams of salt a day - twice the recommended maximum and three times what they need - but that children, who require even less, are actually consuming the same amount. This is thought to be due to their high intake of fast foods, salty snacks and even breakfast cereals, some of which are as saline as Atlantic sea water.

According to Graham MacGregor, professor of cardio-vascular medicine at St George’s Hospital, south London, and chair of both Cash and the Blood Pressure Association, this high intake at an early age is likely to have serious consequences in later life.

“If you feed salt to young animals, you tend to get irreversible changes that make it much more likely they will develop higher blood pressure,” he says. “If we didn’t eat salt at all - and humans didn’t have access to it until about 5,000 years ago - none of us would have high blood pressure.

Which is why we aim is to get intake down in children from the day they are born.”

A big stumbling block, says Professor MacGregor, has been the food industry (75 per cent of our salt intake comes from processed foods, including bread). He doesn’t mince words when laying the blame for poor diet squarely at its door.

“The food industry is criminal in the way it markets rubbish products to children,” he says. “These completely useless foods are mainly fat. They then add lots of salt and sugar and spend huge amounts on marketing them rather than selling good food, which is what they should be doing.

“If you got all the world’s nutritionists together and asked them to design a diet for children that was going to cause vascular disease or furring of the arteries as they got older, what they came up with would be what we’re feeding them now. It’s almost as though the food industry is experimenting to see how quickly they can kill everyone off.”

Research shows that at least 35,000 deaths from strokes and heart attacks in the UK could be prevented each year if we halved our salt intake, says Professor MacGregor. He believes that in years to come this issue will be viewed in the same light as smoking is viewed now.

“I think the food industry knows that. But it’s a case of trying to get them to move now rather than killing off a few more hundred thousand people with their awful foods.”

Meanwhile, Cash is trying to eliminate confusing labelling. The public health minister, Melanie Johnson, has warned the food industry that it must act before next month or risk having products labelled as “high in salt”.

Salt increases thirst: the high intake among children causes an increase in fluid consumption of 350ml per day. Given that children are more tempted to quench their thirst with sweet, carbonated drinks, Cash argues that salt is a factor in the rising incidence of obesity and tooth decay.

There is also evidence that high blood pressure is associated with abnormalities of calcium metabolism, predisposing an individual to osteoporosis and kidney stones. This would mean that girls with high salt intake as they approach puberty may be storing up additional trouble.

How easy is it for someone who is used to the taste of salt to reduce their intake significantly? On this score at least, Professor MacGregor has some good news.

“If you stop eating salt,” he says, “it takes a month to six weeks for your salt receptors to adjust. Then it’s like cutting out sugar in tea and coffee. You wonder how you ever liked it in the first place.”

Cash will be holding its fifth National Salt Awareness Day on January 28.

For information on this and other salt-related issues, and for guidance on interpreting food labels, visit www.hyp.ac.ukcash