Russ Lyons sends along this news article by Ian Johnston, who writes:
The prestigious medical journal The Lancet has been attacked for publishing an academic paper that claimed eating too little salt could increase the chance of dying from a heart attack or stroke.
Johnston summarizes the study:
Researchers from the Population Health Research Institute in Canada, studied more than 130,000 people from 49 different countries on six continents and concluded people should consume salt “in moderation”, rather than trying to reduce it in accordance with government guidelines across the world. . . .
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.
Among 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.
But there are critics:
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”.
Now I don’t know what to think. I really don’t. I haven’t looked at the paper or the criticisms. If the study really is so flawed, though, I can’t say I’m surprised that it was published in the Lancet, a journal that’s famous for producing headline-grabbing papers that are later refuted, such as that Iraq survey, or that article claiming that gun laws could reduce firearm deaths by 200% or whatever, or, most notoriously, that paper by Andrew Wakefield [no link needed]. The Lancet may well publish some high-quality work but they do seem to have a weakness for bold claims and publicity.
I suppose the Lancet will publish a letter by Cappuccio or someone else with the criticisms? Perhaps a reader can keep us up to date here.
P.S. I’m sure I eat too much salt for my own good. I have a big jar of pretzels just sitting here in my office!