It takes a mere 30 minutes for a single salty meal to constrict the blood flow in your arteries. Scientists tested how quickly salt had a damaging effect on the body by recruiting healthy adults and feeding them each a high-salt meal, containing four grams, and later a low-salt meal, made with just 0.3 grams. Before and after each meal, they tested how smoothly blood was flowing in the brachial artery - the main blood vessel in the upper arm which is normally used for checking blood pressure, the American Journal of Clinical Nutrition reports. Although the artery does not measure blood flow directly to the heart, it is commonly used to give an indication of cardiovascular health, according to the Daily Mail , which quoted the journal. In a report on the findings, the authors from a group of research organisations in Adelaide in Australia said: "This study showed the amount of salt similar to that in a commonly eaten meal impairs blood flow in healthy men and women." Graham MacGregor, chairman of the UK-based lobby group Consensus Action on Salt and Health, said: "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," he added. The daily recommended amount in the UK is no more than 6 gm, but it is estimated that most people eat around 8.6 gm. Health experts estimate that cutting average consumption by just a couple of grams a day would slash strokes by 22 per cent and heart attacks by 16 per cent.