Eating less salt lowers your stroke risk. And it doesn’t have to be boring.

It’s been called a divine substance. All over the world and throughout history, it has been associated with sex, with religion, with magic. It has provided an answer to everyday needs. Today its uses are said to exceed 14,000, from making drugs to dyeing textiles. I’m talking about salt.

Today sees the start of Salt Awareness Week which, this year, is focusing on reducing salt intake to achieve lower blood pressure and so lower risk of stroke. Consensus Action on Salt & Health is accompanying the campaign with suggestions on their website for ways to reduce salt intake and a guide to food labels. Salt is also called sodium chloride and sometimes food labels only give the figure for sodium. You can work out how much salt is in something from the sodium figure by this calculation: salt = sodium x 2.5. Around 75% – 80% of the salt we eat is already in foods such as bread, breakfast cereals and ready-meals. On average in the UK, we eat around 9.5g of salt (3.7g sodium) a day.

The Department of Health recommends a maxiumum daily salt intake:

  • Aged 11 and over: 6g (2.4g sodium)
  • 7 to 10 years: 5g salt a day (2g sodium)
  • 4 to 6 years: 3g salt a day (1.2g sodium)
  •  1 to 3 years: 2g salt a day (0.8g sodium)

A Cochrane review has brought together the evidence on the impact of reduced salt intake on blood pressure.The reviewers searched relevant databases and reference lists for randomised controlled trials (RCTs) which assessed reduced salt intake over at least four weeks. They included 31 RCTs with 3022 adult participants, who had raised blood pressure in 20 RCTs and normal blood pressure in 11 RCTs.

  • Reduced salt intake had a significant effect on blood pressure, which fell, on average, by 5/3 mmHg in people with raised blood pressure 2/1 mmHg and in people with normal blood pressure
  • Within the range of 3 to 12 g of salt intake/day, the lower the salt intake, the lower the blood pressure
  • There were no significant adverse effects (harms) resulting from salt redcution
  • The included studies lasted, on average, for five weeks, so they do not provide evidence on the longer-term impact of salt reduction

The authors comment that:

“Current recommendations to reduce salt intake to 5-6 g/day will have a major effect on blood pressure and therefore cardiovascular disease [stroke, coronary heart disease and heart failure] , but are not ideal. Reducing salt intake further to 3 g/day will have additional large effects.”

And while you are looking at ways to cut down the salt in your diet, you could look to history for some more unusual suggestions for using it. A Paris engraving from 1157 shows women salting their husbands, in order to make them more virile. Two men are depicted in some sort of tub, one head down presenting a defenceless backside and the other looking appalled, while a bunch of determined-looking women salt them “front and back” so that “at last, strong natures they will not lack”. I dread to think what that did for the poor blokes’ stroke risk…

Links:

Consensus Action on Salt and Health: Salt Awareness Week

NHS Choices: daily salt recommendations

He FJ, MacGregor GA. Effect of longer-term modest salt reduction on blood pressure. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD004937. DOI: 10.1002/14651858.CD004937. This review is available as a Cochrane Summary

For a fascinating history of salt see Kurlansky M. Salt: A World History. Vintage 2003. ISBN 0 09 928199 6

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Sarah Chapman

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My name is Sarah Chapman. I have worked on systematic reviews and other types of research in many areas of health for the past 17 years, for the Cochrane Collaboration and for several UK higher education institutions including the University of Oxford and the Royal College of Nursing Institute. I also have a background in nursing and in the study of the History of Medicine.

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