No strong evidence exists that advising people to eat less salt or putting them on a low-salt diet reduces their death rate or cuts cardiovascular events, an analysis of seven studies found.
The report combined the results of seven previous randomized clinical trials that looked at the effects of lowering salt consumption in 6,250 people with normal and high blood pressure. While patients in the reduced-salt groups lowered their blood pressure, there was no significant difference in mortality rates. Still, the number of patients wasn't large enough to exclude "clinically important effects" of reduced salt on mortality, wrote Rod S. Taylor, a University of Exeter researcher and lead author of the analysis published today in the American Journal of Hypertension.
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"They found that we don't have sufficient evidence to know whether it would be good or bad," Michael Alderman, an epidemiologist at the Albert Einstein College of Medicine in New York and editor-in-chief of the hypertension journal, said in a telephone interview. "I don't think it is a game-changer, I just think it reminds us that we don't have the evidence we need."
Public health authorities in most developed countries recommend reducing salt intake by roughly half. In the study, the British researchers wrote that while the inconclusive findings "are consistent" with the idea that lowering salt consumption is beneficial, the results don't provide good evidence to support the theory that advising people to eat less salt will save lives.
Alderman said in a telephone interview he is skeptical of widespread calls for large reductions of sodium intake. He said he has been an unpaid adviser in the past to the Salt Institute, an industry trade group.
A study in the Journal of the American Medical Association published in May of 3,681 Europeans followed for 7.9 years found that lower salt excretion was associated with a higher risk of cardiovascular death.