War on salt

I’ve read enough here and there through the years to be very skeptical of all the “you’ve got to reduce your sodium intake” messages out there.  For some small subset of the population, reducing sodium is probably important, but for most healthy Americans– even for many with high blood pressure– you are probably just wasting your time worrying about your salt intake.  Thus, I was very pleased to see this excellent Scientific American article about the lack of evidence for harmful effects of dietary sodium (and another shout-out to facebook and my interesting lot of FB friends for bringing me an article I would have otherwise never known about).  Anyway, here’s the gist:

This week a meta-analysis of seven studies involving a total of 6,250 subjects in theAmerican Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure. In May European researchers publishing in the Journal of the American Medical Association reported that the less sodium that study subjects excreted in their urine—an excellent measure of prior consumption—the greater their risk was of dying from heart disease. These findings call into question the common wisdom that excess salt is bad for you, but the evidence linking salt to heart disease has always been tenuous.

Given what we know about the inflated threat of saccharine from my youth, I was especially intrigued to see the evidence based on animals studies:

Worries escalated in the 1970s when Brookhaven National Laboratory’s Lewis Dahl claimed that he had  “unequivocal” evidence that salt causes hypertension: he induced high blood pressure in rats by feeding them the human equivalent of 500 grams of sodium a day. (Today the average American consumes 3.4 grams of sodium, or 8.5 grams of salt, a day.)

It’s not that there’s no studies that say salt is bad for you, it’s just that there’s just as many well-designed studies that suggest it is basically harmless.  It also may be that extreme hyper-sensitivity to salt among a small portion of the public leads to a statistically significant effect even though the vast majority of the population is unaffected.  So, pull out that salt shaker.

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