Eating a single salty meal reduces blood flow in your main arteries in just 30 minutes
By PAT HAGAN,
Daily Mail
1st March 2011
Salt was found to rapidly stiffen arteries - thought to be an early sign of heart disease
A salty diet may damage the heart by making blood vessels 'stiffer'
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Blood flow in the body's main arteries is significantly reduced within half an hour of eating just one meal high in salt, alarming new research shows.
Doctors found arteries rapidly lost some of their ability to pump blood because of the damaging effects of salt.
Experts believe the findings may help to explain why the popular food additive is so harmful.
Until now, it was thought to increase the risk of heart attacks and strokes by driving up blood pressure.
But the latest study, by a team of Australian scientists, shows salt may also damage the heart by making blood vessels 'stiffer' and less able to keep blood moving round the body.
British experts last night warned the amount of salt in the meals used for the study, at 4g per portion, is what many consumers probably get through in an average evening meal.
Professor Graham MacGregor, chairman of the lobby group Consensus Action on Salt and Health, said: 'This research is of great interest. It clearly shows a rapid effect on the stiffness of the blood vessels.
'It looked at the effects of eating just 4g of salt. That's not particularly high and is probably average for many meals consumed in the UK. In fact, if you eat out you will probably consume more than that.
'This kind of damage to the blood flow is thought to be a very early sign of heart disease. Every time you eat a salty meal you are altering the function of the cells that line your arteries.'
Salt has been linked with an increased risk of heart attacks, strokes, kidney disease, osteoporosis and stomach cancer.
The daily recommended amount in the UK is no more than 6g. But it is estimated that most adults eat around 8.6g.
Research by the Health Supplement Information Service shows daily salt intake among seven to 14-year-olds was 6.4g for boys and 5.6g for girls.
Bread, processed foods and ready-made sauces are some of the items that contain the highest salt levels, although supermarkets have gradually been reducing salt levels in oven-ready meals.
Health experts estimate that cutting average consumption but just a couple of grammes a day would slash strokes by 22 per cent and heart attacks by 16 per cent, saving 17,000 lives in the UK.
Scientists from a group of research organisations in Adelaide, Australia, wanted to see how quickly salt had a damaging effect on the body.
They recruited 16 healthy adults and fed them each a high-salt meal, containing 4g, and later a low-salt meal, made with just 0.3g.
Before and after each meal, they tested each volunteer's flow-mediated dilation.
This is a measure of how smoothly blood is flowing in the brachial artery, the main artery in the upper arm which doctors normally use to check blood pressure.
Healthy blood vessels will stretch open to let more blood pass through easily but damaged ones are less flexible and restrict the flow.
Although the brachial artery does not measure blood flow directly to the heart, it is commonly used to give an indication of cardiovascular health.
The results, published in the American Journal of Clinical Nutrition, showed blood flow was 'significantly more impaired' within 30 minutes of eating the salty meal than the low-salt alternative and the restriction reached a peak after an hour.
In a report on the findings researchers said: 'This study showed the amount of salt similar to that in a commonly eaten meal impairs blood flow in healthy men and women. The mechanisms for this need to be investigated more intensively.'
Victoria Taylor, senior dietician at the British Heart Foundation, said the findings reinforce the need to cut down intake.
'As this research suggests, salt may affect our heart in a variety ways - not just through raised blood pressure.
'Although we have seen improvements in the amount of salt we are eating in the UK, there is still some way to go.'
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