Americans should slash their consumption of salt by half says a new government report. But the recommendation has no basis in science and may even be harmful to your health. "Healthy 19-to 50-year old adults should consume no more than 1,500 milligrams of sodium per day," recommended a panel of the National Academy of Sciences Institute of Medicine (IOM). That's quite a reduction from the currently recommended 2,400 milligrams of sodium per day and average consumption of more than 4,000 milligrams per day. Too much dietary salt increases blood pressure which, in turn, may lead to stroke, coronary heart disease - or so the IOM panel claims.
Existing scientific data, however, do not support this commonly-held belief. Dietary salt may, in some sensitive people, slightly increase their blood pressure, but it's not clear that the increase leads to health effects or that restricting their intake of salt makes them any healthier. Since 1995, 10 studies have reported on whether lower sodium diets produce health benefits. All 10 studies indicate that, among the general population, lower sodium diets don't produce health benefits. In fact, not a single study has ever shown improved health outcomes for broad populations on reduced sodium diets.
Just last week, in fact, a coalition of six Canadian medical groups rejected a recommendation for universal salt restriction, choosing instead to make lifestyle recommendations for reducing blood pressure such as exercising, eating a balanced diet, and stress management. The IOM would be on firmer ground if it limited its recommendation to "salt sensitive" individuals, rather than the general public. Genetic background and lifestyle make some people hypersensitive to salt intake. The IOM panel recommendation is "nonsense," said Dr. Lawrence M. Resnik, executive editor of the American Journal of Hypertension and a professor at Cornell Medical College.
Resnick was a member of the IOM panel until his resignation over the panel's disregard for testimony and data that contradicted its apparently predetermined recommendation. Dr. Alexander Logan, co-author of the Canadian recommendations, observed that the difference between the Canadian and US recommendations came down to process. The Canadian recommendations were based on a rigorous examination and consideration of the available scientific evidence according to an established protocol whereas the IOM panel operated under "no rules" " that is, without regard to scientific standards and process " according to Dr. Logan.
The conduct of the IOM panel is made more egregious by the fact that its recommendation may very well place some people at risk. Studies by hypertension specialist and American Hypertension Society past-president Michael Alderman even report an increased risk of heart attack and a higher death rate among some individuals on low-salt diets. Since no data supports limiting sodium intake to 1,500 milligrams per day, you might wonder why the IOM panel would urge such an uncontrolled experiment on the general public. An IOM panel member who didn't want to be identified indicated that one of the panel's goals was to get African-Americans, who tend to be more salt sensitive, to reduce their sodium intake.
But because the panel didn't think that singling out African-Americans was an effective public health strategy, it decided to "overcompensate" and make the recommendation for the general population - thereby shifting the burden to the food industry to reduce salt content in foods. African Americans, then, couldn't help but eat less salt. Another motivation is more political. The US Health establishment's official position, as espoused for the last 30 years by the National Institutes of Health, is that everyone should restrict their salt intake. Regardless of the science, the NIH is not about to admit it's been wrong - even to the extent of refusing to make publicly available all the data on which the current dietary salt recommendation is based.
Fortunately for the NIH, the IOM panel was well stacked with sycophants that could be relied on not to bite the hand that feeds them. A majority of the IOM panel, including chairman Lawrence Appel, all receive research grants from the NIH. In an effort to make the food industry rather than the NIH the problem, Dr. Appel told the Associated Press, "There are commercial interests that don't want this to happen." But why should the food industry be forced to sell less tasty food for no good reason? More importantly, does it really make sense to experiment with the public health so that government bureaucrats don't have to admit they've been wrong for the last 30 years? Steven Milloy is the publisher of JunkScience.com, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-Defense Against Health Scares and Scams (Cato Institute, 2001).