For decades, public heath bodies have been advising us that reducing our salt intake could reduce blood pressure, helping us to live a longer and healthier life. But is this advice based on science? A long-running debate fuelled by reports in the medical journals, and a recent investigation by the journal Science, have highlighted how much scientists disagree about the level of salt that constitutes a healthy intake. Many researchers conclude that if reducing salt intake has any benefit to health, the benefit may be much smaller than we are led to believe. A study published this week in the American Heart Association?s journal Hypertension now adds to the debate, showing that our genetic make-up may determine whether or not we could benefit from a low-salt diet.
The controversy is not surprising, as for every patient that is found to respond favourably to a low-salt diet with a reduction in blood pressure, another person is found to tolerate to an extremely high-salt diet without any noticeable change in blood pressure. Put all these people together into a large scale survey, and the individual effects disappear into statistical insignificance. To add to the confusion, it is very hard to separate out other aspects of the diet which might also affect blood pressure, such as the amount of fresh fruit and vegetables consumed, or the amount of fat, or alcohol - the list goes on.
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