Scores of health authorities around the world advise that we should aim to reduce our salt intake from the roughly 9 to 12 grams a day we eat now down to around 6 grams - about a teaspoonful a day. Since around 75 percent of all the salt we consume comes from packaged and processed food, rather than from what we sprinkle on top of it, food manufacturers have been in the firing line.

Under pressure from health authorities and the WHO, the food industry - which stands accused of using salt to boost the flavor, shelf-life and profit of what would otherwise be bland ingredients - has taken action. Big brands like Heinz, Kellogg’s, Nestle, Pepsico, General Mills and others have been steadily reducing sodium levels in their foods.

According to Susan Jebb, a nutrition adviser to the UK government, Britain is leading the way, forcing foodmakers to make some “impressive” reductions including a 30 percent reduction in salt in bread, about a 50 percent cut in branded breakfast cereals and around 25 percent in pasta sauces.

Among the health-conscious at least, a salt-shaker on the dining table is becoming almost as frowned on as an ashtray.

NOT CRYSTAL CLEAR

But the findings that policy-makers have accepted as settled are not as clear-cut among scientists. A study in July by the much-respected Cochrane Library, which conducts meta-analyses of scientific data by grouping together the best studies on a subject and pooling the results, found no evidence that reducing salt intake cuts the risk of developing heart disease or dying before your time.

In that study Rod Taylor, a professor of health services research at Exeter University, analyzed seven randomized controlled trials covering more than 6,500 people and found that although cutting down did appear to lead to slight reductions in blood pressure, this did not translate into lower risk of heart disease or premature death.

In one group of people - those with pre-existing heart conditions - reducing salt was actually associated with an increase in the likelihood of premature death.

Taylor said he did not receive payment from, or have links to, the salt industry. His study was funded by a grant from the UK government’s National Institute for Health Research.

Taylor’s study came hot on the heels of another, by Belgian scientists, which was published in the Journal of the American Medical Association (JAMA). That found people who ate lots of salt were no more likely to get high blood pressure, and were statistically less likely to die of heart disease, than those with low salt intake.

The researchers used data from two different studies, involving a total of around 3,700 Europeans whose salt consumption was measured through urine samples. The scientists divided the participants into three groups with low, medium and high intake: those with the lowest salt intake had the highest rate of death from heart disease - at 4 percent. People who ate the most salt had the lowest death rate from heart disease, at less than 1 percent.

“One should be very careful in advocating generalized reduction in sodium intake in the population at large. There might be some benefits, but there might also be some adverse effects,” says Jan Staessen, head of hypertension studies at the University of Leuven and the lead investigator on the Belgian study. “You have to ask, should public health policies be based on something which is still being debated? I don’t think so.”

Staessen told Reuters he had no financial conflicts of interest. His work was funded largely by grants from the European Union and European national governments.