Most people - even some with high blood pressure - shouldn't worry about shaking on the salt, according to a new study that challenges the conventional wisdom among doctors and government experts.
The report by Canadian researchers concludes that while a salt-restricted diet can lower blood pressure in hypertension patients over age 45, it has little or no benefit among younger hypertension patients and those with normal blood pressure, the vast majority of the population."We feel people can probably stop worrying about salt," writes the study's co-author Alexander Logan, an epidemiologist and high blood pressure specialist at the University of Toronto.
The analysis of 56 previous studies was paid for in part by the Campbell Soup Co., which has been criticized by the U.S. government and interest groups for touting the health benefits of its salt-laden soups.
The report appears in Wednesday's Journal of the American Medical Association in an issue that focuses solely on high blood pressure, which afflicts some 50 million Americans. It also includes a study underscoring the link between high blood pressure and heart disease and one emphasizing effectiveness of diet, exercise and drugs in treating hypertension.
In an accompanying editorial, Dr. Claude Lenfant, director of the National Heart, Lung and Blood Institute, challenged the Canadian report because it includes several studies of less than two weeks' duration.
"The preponderance of evidence continues to indicate that modest reduction of sodium, as recommended in the 1995 U.S. Dietary Guidelines for Americans, would improve public health," Lenfant wrote.
Prompted by research linking high-sodium diets with high blood pressure, the U.S. government has been warning Americans since the early 1980s to go easy on salt. The recommended daily allowance is 2,400 milligrams, though average daily consumption is about 3,900.
Meanwhile, a report in the May 18 edition of the British Medical Journal found conflicting results, concluding that dietary salt guidelines are warranted and recommending a one-third reduction in daily salt consumption.
The British researchers, reanalyzing data from a 1988 study of more than 10,000 people, said the latest study found "overwhelming" evidence that higher salt intake is associated with higher blood pressure.