AN ARTICLE in a leading science journal has ignited a heated debate about
whether eating large amounts of salt leads to high blood pressure. The journal
has come under fire for failing to state prominently that the author of the
article, which questions the idea that salt causes hypertension, has links with
the food industry.
Many researchers believe that a high salt intake can cause high blood
pressure, which in turn can lead to strokes and coronary heart disease. But in a
signed editorial in last week鈥檚 Science (vol 281, p 933), David
McCarron of Oregon Health Sciences University in Portland disputes that
link.
McCarron believes the idea is a fad that has been hyped by nannying public
health officials. 鈥淭his is a superb example that started in the 1970s of public
policy being ahead of the scientific facts,鈥� he told 快猫短视频. He
says blaming salt is harmful, as it deflects attention from deficiencies in our
diets, such as lack of fruit and vegetables, that are 鈥渇ar more likely to
contribute to the prevalence of hypertension than salt鈥�.
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The article has prompted an angry response. 鈥淚t鈥檚 full of distortions,鈥� says
Graham McGregor, a specialist in blood pressure at St George鈥檚 Hospital Medical
School in London. He says the article fails to acknowledge controlled studies in
Portugal and Holland which show that reduced salt intake can significantly lower
blood pressure. And the article unfairly dismisses results from chimpanzee
studies as irrelevant, according to McGregor.
The US Center for Science in the Public Interest has attacked
Science for failing to make McCarron鈥檚 links to the food industry clear.
鈥淭he public should know McCarron鈥檚 work is part of an effort by the food and
salt industries to discredit the evidence linking salt and hypertension,鈥� says
Bonnie Liebman, the centre鈥檚 nutrition director. 鈥淚t is unfortunate that
Science chose not to fully reveal his industry connections.鈥�
McCarron is a consultant to the Salt Institute, a salt traders鈥� organisation
based in Virginia, from which he receives $3000 a year. The affiliation
is mentioned in Science鈥攂ut not in McCarron鈥檚 editorial. It
appears only halfway through an accompanying news focus which is nine pages
long. 鈥淚t鈥檚 so long and boring I doubt anyone other than those with a special
interest in the subject would read it,鈥� says McGregor.
Neither article mentions that McCarron receives grants from the US National
Dairy Council. However, a spokeswoman for Sciencesays: 鈥淲e鈥檙e happy
about the validity and integrity of both articles.鈥�
McGregor says it is in the interests of food manufacturers to downplay the
link between salt and high blood pressure because so many foods contain large
amounts of salt for flavouring. 鈥淒rinks manufacturers have an interest too,
because salt is the most important factor in causing thirst,鈥� he adds.
McCarron counters that it鈥檚 not who pays for the research that matters, but
whether the results of studies can be verified. He says his opponents failed to
take into account recent reviews of the data, such as a study reported last year
in Archives of Internal Medicine (vol 157, p 1117) which found no
evidence that salt causes hypertension.
Other researchers, including Theodore Kotchen of the Medical College of
Wisconsin, agree that diets rich in potassium, calcium, magnesium and fresh
fruit, and low in fat, could help fight hypertension. But he believes excess
salt is also a major factor.
In Britain, a meeting of experts in December hosted by the British Heart
Foundation is sending its recommendations to the government鈥檚 Chief Medical
Officer, repeating earlier advice that an adult鈥檚 daily salt intake should be
cut from the national average of 9 grams to 6 grams.