WebMD: stick to weight loss
WebMD ran a feature last month, "5 Easy Ways to Cut Back on Salt," by Elaine Magee of its Weight Loss Clinic. She should have stuck with weight loss where she's likely an expert. She started off correctly stating that that the latest study of cardiovascular outcomes of limited salt diets found low-salt dieters "37% more likely to diet of cardiovascular disease." But she then dismissed this important finding with an erroneous statement: "this is just one study, compared to scores of others that have found health benefits to avoiding a high sodium diet."
She's wrong on both counts. It's not the only study finding additional population risk for low-salt dieters and, far from there being "scores of others that have found benefits" for reducing salt, not a single study has identified such a population health benefit.
That is true, of course, depending on how one defines “benefit.” We think it is the net effect of an intervention. Low-salt diets can lower blood pressure in some people, but they also raise insulin resistance, increase sympathetic nervous system activity and, especially, cause plasma renin activity to skyrocket -- all of which contribute to increased rates of heart attacks and offset the "normal" benefits of lower blood pressure. In fact, there have not been "scores" of studies at all, in total -- just a baker's dozen. Three find serious additional risk. None, however, are the high quality controlled trial that should be used to guide such policy.
The Salt Institute has called for a five-year study of the cardiovascular and all-cause mortality of diets reduced in sodium. Let's settle this question with hard evidence, not conjecture and extrapolation of selected intermediate variables.
