Potassium and Blood Pressure
Ask anyone that knows me can tell you I love potassium. Its physiology, treatment of its disturbances, and its magical effects. I’ve also used it myself in my armamentarium to treat my own hypertension. When I tell people I sprinkle potassium on everything, the look at me like I’m crazy but potassium has some impressive anti-hypertensive effects. The earliest of which were first discovered about 80 years ago by Keith and Binder in which they determined that potassium salts had some type of diuretic effect.
We now know from several large epidemiological studies that dietary potassium intake is inversely related to BP. Several mechanisms are involved including inhibition of thiazide-sensitive NCC in the distal nephron. At ASN there was an entire block dedicated to K and BP, and there is some new evidence that the effect of potassium on the NCC cotransporter may be due to plasma potassium directly by influencing intracellular chloride, an inhibitor of the with-no-lysine kinase (WNK)-Ste20p-related proline- and alanine-rich kinase (SPAK) pathway (Terker et al. KI 2015 http://www.ncbi.nlm.nih.gov/pubmed/26422504). Even more interesting is that the ratio of dietary sodium to potassium may be more important (Cook et al. http://www.ncbi.nlm.nih.gov/pubmed/19139321). From a subgroup analysis from this systematic review by Aburto et al, it would appear that effects were most beneficial at 90-120 mEq/day with a decrease in BP by 7.2/41 mmHg. But in the recent GenSalt study it found that we could get benefits with a potassium intake as low as 60 mEq showing as reduction of 4/2.2 mmHg initially, and 3.9/1.8 mmHg at longer (4 year) follow up.
How serum potassium affects intracellular Cl-dependent WNK4 and ultimately NCC. (Terker KI 2015)
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