Potassium Simply Explained

1. What Is Potassium?

Potassium is a mineral that the body needs for many processes. It counts among the electrolytes, that is, substances dissolved in body fluids. The body takes in potassium through food. In studies, potassium is examined as a component of the diet or as a salt in capsules or powders. Most often it concerns blood pressure and cardiovascular function.

2. Where Is It Found, and What Is It Made From?

Potassium is naturally present in almost all plant and animal cells. It is especially abundant in fruit, vegetables, legumes and potatoes. For dietary supplements, potassium salts are obtained from mineral deposits such as sylvite or from salt lakes. In studies, mainly potassium chloride, potassium citrate, potassium bicarbonate and potassium gluconate are tested, as well as potassium from food.

3. What Does Potassium Do? What Research Shows

Blood Pressure

Many good studies show that more potassium can lower blood pressure. The effect is clearer in people with high blood pressure than in people with normal blood pressure 3478911. The reduction was especially clear when potassium was given as a preparation or as a salt substitute 53336. With potassium from food, by contrast, the results are inconsistent 393438. With very high additional intake, the effect diminished, and in people who already take blood pressure medications, blood pressure even rose 14.

Cardiovascular

In people after a stroke, a salt substitute of potassium chloride and sodium chloride lowered mortality 16. A potassium-rich meal mitigated a short-term vascular effect after the meal in healthy people 38. Other studies found no difference: Less frequent potassium administration after heart surgery did not lead to more cardiac rhythm disorders 18, a potassium binder during dialysis did not change cardiac rhythm events 17. The evidence is moderate; it remains unclear which potassium form and amount benefits which groups.

Kidney

In people on dialysis with too much potassium in the blood, potassium binders reduced how often the potassium level was too high 237. Some of these agents also lowered the potassium level, others not reliably 2. A changing potassium profile in the dialysis fluid lowered the potassium level after dialysis more than a constant one 32. In healthy people, a potassium preparation changed kidney function: It retained more water in the body 40. Most of these studies were small and short, and several tested mixtures 2325.

Diabetes

For diabetes, there are only a few studies so far, and they do not show a uniform picture. In a study with an adapted DASH diet, which among other things contained more potassium, a long-term blood sugar value decreased similarly in both groups in pregnant women with diabetes 31. A study with magnesium and potassium preparations found no difference in quality of life and cholesterol 22. The evidence is low, because the studies examined different forms, mixtures and groups.

Muscle

For muscle, there are only a few studies so far with weak evidence. Older healthy people who took potassium bicarbonate, partly together with whey protein, were not at an advantage in muscle strength, physical performance and muscle mass 26. In knee osteoarthritis, a potassium salt of glucosamine performed no better than the sodium variant of the same substance 28. The studies are small and examined different forms and groups. It remains open whether other potassium forms or higher amounts have an effect in certain groups.

Bone

For bone, there are only a few studies so far with weak evidence. A study with potassium chloride capsules in people with mildly elevated blood pressure found changes in phosphate and calcium values, while other bone values remained the same 35. A large study with a salt substitute of potassium chloride and sodium chloride found no difference in the frequency of fractures in adults at high cardiovascular and fracture risk 15. In an observational study in knee osteoarthritis, more potassium from food was not associated with the structure of the knee joint 43. It is open whether potassium without sodium chloride influences bone strength.

Stroke

In stroke prevention, the results differ depending on the form and use of potassium. A study with a salt substitute of potassium chloride and sodium chloride found fewer recurrent strokes in stroke survivors in northern China 16. In people who newly took a diuretic medication, additional potassium in an observational study was not associated with strokes 44. The evidence is low, because only one controlled study (with a comparison group) is available. It remains open whether potassium alone lowers stroke risk.

Other Investigations

Urinary potassium excretion increased with potassium chloride preparations 2433 and after a short medical nutrition counseling 42. In dialysis patients with too much potassium in the blood, a potassium binder kept the potassium level within the normal range better than a sham preparation over twelve months 17. Bananas at the start of dialysis kept the potassium level higher during dialysis and made a too-low potassium value less common 27. The evidence is moderate: There is a review and many controlled studies, but the forms and groups examined are very different. Potassium chloride, potassium citrate, potassium bicarbonate, potassium gluconate, potassium aspartate, potassium from food as well as potassium binders, partly as mixtures with sodium or magnesium, were tested.

4. How Was Potassium Taken in the Studies?

In the studies, potassium was given in various ways: as potassium chloride, potassium citrate, potassium bicarbonate, potassium gluconate, potassium aspartate, or as potassium from food. Sometimes it was mixed with sodium chloride, for example as a salt substitute, or combined with magnesium. For dialysis patients with too much potassium in the blood, potassium binders such as patiromer or sodium zirconium cyclosilicate were also used. The amounts, time periods, and preparations varied greatly.

5. Is Potassium Safe? Side Effects in the Studies

In a review, adverse events and discontinuations occurred more often with potassium 9. The results apply in each case only to the potassium form and preparation examined. Potassium from food acted differently in the studies than potassium as a preparation or as a salt substitute. In kidney disease, the potassium level in the blood rose with a more potassium-rich diet, too high in two participants 39.

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