The prestigious British medical journal The Lancet is being attacked for promoting the use of salt by publishing an academic paper that claims eating too little salt could increase the chance of dying from a heart attack or stroke.
The paper presents a study by researchers from the Population Health Research Institute in Canada, of more than 130,000 people from 49 different countries on six continents and concludes that people should consume salt ''in moderation'', rather than trying to reduce it.
This is in contrast to government guidelines across the world that while salt is essential its excessive use does more harm than good.
Several scientists have criticised the paper with one eminent expert expressing ''disbelief'' that ''such bad science'' should be published by The Lancet.
The paper compared the health of people who tests showed had consumed low levels of sodium (up to three grams a day), medium amounts (four or five grams) and high levels (seven grams or more).
''Those participants with four to five grams of sodium excretion had the lowest risk'' of death or suffering a ''major cardiovascular disease event'', the researchers reported.
Recent research revealed that salt levels in everyday foods have soared and for people who had high blood pressure, eating high and low levels of salt ''were both associated with increased risk''. And for people without high blood pressure, consuming less than three grams a day was ''associated with a significantly increased risk'' – 11 per cent – of death or a serious cardiovascular event.
Dr Martin O'Donnell, a co-author on the study and an associate clinical professor at McMaster University in Canada, said, "This study adds to our understanding of the relationship between salt intake and health, and questions the appropriateness of current guidelines that recommend low sodium intake in the entire population.
"An approach that recommends salt in moderation, particularly focused on those with hypertension, appears more in-line with current evidence."
However Professor Francesco Cappuccio, head of the World Health Organization's Collaborating Centre for Nutrition, attacked both the methods used in the study and the journal for agreeing to publish it.
''It is with disbelief that we should read such bad science published in The Lancet,'' he said.
Professor Cappuccio said the article contained ''a re-publication of data'' used in another paper.
''The flaws that were extensively noted in their previous accounts are maintained and criticisms ignored,'' he said.
The measurement of salt intake used by the researchers, he said, was ''flawed'' because it was done by testing urine samples given in the morning and then ''extrapolated to 24-hour excretion" using an "inadequate" equation.
Professor Cappuccio also said the participants were ''almost exclusively from clinical trials of sick people that have a very high risk of dying and are taking several medications''.