Monday, November 13, 2023

Read the article carefully

This article from CNN claims that moderate reductions in salt will have a major effect on blood pressure, working "as well as blood pressure meds".  Reality? Well, they took a standard American diet's intake of sodium (about 4000mg), added a teaspoon's worth of salt to the mix (2300mg), and then the next week,  cut sodium intake to 500mg (about as low as you can go without going into sodium deficiency, ahem).

End result?  Blood pressure readings dropped by about 8 mm of Hg.  To draw a comparison, my very low dose (5mg) of licinopril drops my blood pressure by about twice that, and my wife is taking a dose about 10x higher.  Typical diagnoses for high blood pressure are in the 160/110 range and up, and the target blood pressure is 120/80.  

Don't get me wrong; I'll take an 8mm or even 1mm reduction in blood pressure with reasonable measures, but this isn't going to let anyone drop their blood pressure meds, and may even be somewhat hazardous.  When you drop your intake of a vital nutrient (sodium is one of those things that keeps your heart beating) to the absolute minimum, you're getting into the realm where small errors can make a huge difference in your health.

Chalk this one up to an adage I like: Nobody gets their PhD, tenure, or big promotion in research by retaining the null hypothesis.  Read the article and look for the actual numbers, not the claims by the editor who wrote the headline.

Update: even more interesting is the lead investigator's claim that it's the first study to show that people already on blood pressure medication can further drop blood pressure by dropping sodium. I know from experience that cardiologists have been recommending patients with high blood pressure drop sodium for at least the past 40 years, and I suspect that I'd see the same going back at least 60 years if I look carefully at 1960s era insurance company ads in National Geographic.  If the claim is true, it's long past time for this study to have been done.

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