Here's What's Shakin' With Salt
"The evidence supporting the need for a reduction in dietary sodium intake is convincing and supports the appropriateness of the current U.S. dietary guidelines. As noted, this guideline may not be set low enough to prevent the development of hypertension ... If this goal can be reached, perhaps even greater reductions will be feasible in the future," writes Kaplan.
David McCarron, MD, a professor of medicine at the Oregon Health Sciences University, writes that the current recommendations are based on faulty old studies that vilified salt, not on modern studies and a more sophisticated understanding of the human body. These old studies don't consider genes that can make some people more "salt-sensitive" than others. Nor do they take into account the interaction of other important minerals, such as potassium, that also affect blood pressure. He also makes reference to some newer trials that found reducing salt intake doesn't lead to a lower risk of heart disease deaths, and that it may even increase it.
McCarron argues that by combining the results of these old studies and analyzing them on a large scale, it becomes apparent that people who have normal blood pressure reap very little benefit from reducing salt intake. Additionally, he says, new studies have shown blood pressure is better regulated by adopting the so-called DASH (Dietary Approaches to Stop Hypertension) diet, which includes more fruits, vegetables, and dairy products -- not just by reducing salt. The DASH studies have also suggested that increased potassium, rather than decreased salt, is much more helpful in blood pressure control.
"I would never argue that some people, those who have heart, liver, kidney disease, should watch their sodium intake," says McCarron. But, he says, "we are burning precious resources in terms of public policy" by trying to get the general population to reduce sodium intake.
"By definition, public health policy is intended to promote the health of the public," writes McCarron. Since reducing salt doesn't appear to benefit most of the population in a significant way, since it may not reduce heart disease, and since there are other ways of reducing high blood pressure, the answer to the question 'Should we shake up the dietary guideline for sodium?' is "Unequivocally, yes."