August 25, 2014
A LIFE OF MODERATION:
Dash of Salt Does No Harm. Extremes Are the Enemy. (Aaron E. Carroll, 8/25/14, NY Times)
Posted by Orrin Judd at August 25, 2014 7:09 PM
Americans consume, on average, 3.4 grams of sodium per day, or about the equivalent of three and a half tablespoons of soy sauce. This is on the low end of the "safe zone" of 3-6 grams in the study. The United States Food and Drug Administration thinks that's not low enough. It recommends 2.3 grams per day. The World Health Organization says it should be 2.0 grams. The American Heart Association goes even further and recommends we consume no more than 1.5 grams.Why? There's surprisingly little rationale for this belief. Last year, experts convened by the Institute of Medicine assessed the evidence concerning sodium intake around the world. They agreed that efforts to reduce excessive sodium were warranted. But they cautioned that no such evidence existed to recommend a very low salt diet. They hoped that future research would assess the potential benefits of a diet where sodium intake was 1.5 to 2.3 grams per day.The second New England Journal of Medicine study did just that. In addition to looking at high sodium diets, it also compared the health outcomes of those who had very low sodium diets. What they found was worrisome. When compared with those who consumed 3-6 grams per day, people who consumed less than 3 grams of sodium per day had an even higher risk of death or cardiovascular incidents than those who consumed more than 7 grams per day.This result would be shocking if we in the medical community hadn't seen it before. But we have. In 2011, researchers published a study in the Journal of the American Medical Asssociation after following 3,681 people over almost a decade. They, too, found that excessive salt intake was associated with high blood pressure. They also found that a low-sodium diet was associated with higher mortality from cardiovascular causes.Why experts and organizations feel the need to go from one extreme to the other is unclear. But it's unfortunately something we do far too often in medicine.