Medicine For People!

November 2011 Supplement: Potassium-A Closer Look

Potassium Reviews – How They Work

This review[1] of potassium and blood pressure, done in 2006, claimed there was no benefit. First, they look only at blood pressure and ignore the real issue, survival. Second, the reviewers selected some very few studies of potassium and blood pressure, rejected most others, ran the ones they selected through their food processor, and said "look, no benefit." The trouble is: their analysis conflicts with the most recent large study and with most previous analyses as well. Lesson: select your facts carefully and you can "prove" just about anything.

Most studies show a benefit

The second most recent review[2] of potassium and blood pressure, published nine years earlier in 1997, was an analysis of 33 placebo controlled trials involving 2600 people. Twenty-six of those studies showed a blood pressure reduction with potassium. The authors concluded that potassium supplements did reduce blood pressure.

Why some studies find no hypertension benefit from potassium

The review mentioned just above found that 26 studies showed that potassium lowered blood pressure, and seven did not. Let's look at those seven studies. They involved 529 people. Of those people, 312 were given a quarter to a half of the usual dose. Another 105 received no potassium supplement and were told to eat potassium rich foods, except that urine tests showed they probably didn't. Another 79 had normal blood pressure to begin with. That leaves one study of 33 people reporting no benefit.


While there are a few people who have published studies claiming potassium does not lower blood pressure, strong reasons exist to doubt their conclusions. Even the American Heart Association promotes potassium for high blood pressure.[3]

Additionally, people eating more potassium-rich foods require much fewer blood pressure medications to achieve a normal reading.[4]

Potassium Units

Potassium being a metal, we can administer it only in combination with something else like chloride or gluconate. The amount of potassium in 200 milligrams of potassium chloride differs from the amount of potassium in 200 milligrams of potassium gluconate, 200 milligrams of potassium citrate, and other forms of potassium. So we measure potassium supplements as millimoles to eliminate that problem.


[1] Dickinson HO, Nicolson DJ, Campbell F, Beyer FR, Mason J. Cochrane Database Syst Rev. 2006 Jul 19;3:CD004641. Review.

[2] Whelton PK, He J, Cutler JA, Brancati FL, Appel LJ, Follmann D, et al. Effects of oral potassium on blood pressure. Meta-analysis of randomized controlled clinical trials. JAMA. 1997;277:1624–32

[3] Appel LJ, Brands MW, Daniels SR, Karanja N, Elmer PJ, Sacks FM; American Heart Association. Dietary approaches to prevent and treat hypertension: a scientific statement from the American Heart Association. Hypertension. 2006;47:296–308

[4] Siani A, Strazzullo P, Giacco A, Pacioni D, Celantano E, Mancini M. Increasing the dietary potassium intake reduces the need for antihypertensive medication. Ann Intern Med 1991;115:753-759



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Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington.