CATEGORY: FOODS & NUTRIENTS
Doctors had long noticed that people whose blood potassium sits in the lower half of the normal range suffer more dangerous heart rhythms. Whether pushing that level up would prevent anything was untested. A randomized Danish trial of 1,200 high-risk adults has now tested it: deliberately raising potassium into the high-normal range cut the combined risk of serious rhythm events, unplanned hospital stays and death by 24%. Over a median of just over three years, 22.7% of that group hit one of those outcomes, against 29.2% under standard care alone.1
Potassium Times the Heartbeat, and These Hearts Were Fragile
Potassium is one of the minerals your body uses to generate the tiny electrical impulses that time every heartbeat. Too little of it tracks with a higher risk of ventricular arrhythmias, which are chaotic rhythms arising in the heart’s main pumping chambers. They can be fatal within minutes. Everyone enrolled here carried an implantable cardioverter-defibrillator, a matchbox-sized device placed under the skin that detects such a rhythm and shocks the heart back into step. Needing one is the clearest marker medicine has for high arrhythmia risk.
Food, a Supplement and an Old Pill, All Steered by Blood Tests
Nobody chose their own arm of this trial. A randomization list did it for them. Danish heart centers enrolled 1,200 adults with a defibrillator whose blood potassium sat at 4.3 millimoles per liter or lower, normal but toward the bottom of normal. Half were steered toward a high-normal level of 4.5 to 5.0 using three familiar tools: potassium-rich foods, potassium supplement tablets, and, where needed, a medication in the family of spironolactone, a decades-old pill that helps the kidneys hold potassium instead of flushing it away. The other half continued standard care. Tracking ran for a median of 39.6 months. The main outcome bundled together documented dangerous rhythm events or an appropriate shock from the defibrillator, unplanned hospitalization for rhythm problems or heart failure, and death from any cause.
Twenty-Three Per Hundred Instead of Twenty-Nine
An event struck 136 of the 600 people aiming high and 175 of the 600 on standard care. That is 22.7% against 29.2%, or 7.3 versus 9.6 events per 100 person-years, or a 24% lower risk (hazard ratio 0.76, with a 95% confidence interval of 0.61 to 0.95). Think of tire pressure. Both groups stayed inside the recommended band; one was simply held near the top of it, where there is more margin before trouble. Nor did the approach swap one problem for another, since hospitalizations for potassium that drifted too high or too low were similar in the two groups. Two boundaries sit around all of this. Only high-risk patients with defibrillators were enrolled, so the result says nothing about extra potassium for people in general. And levels were checked repeatedly, with doses adjusted to keep them inside the normal range rather than above it. Potassium is not a more-is-better mineral, and levels above normal carry their own serious rhythm risks, particularly for people with kidney disease.
Key Takeaways
- Among 1,200 adults with implanted defibrillators, targeting high-normal potassium cut the combined risk of serious rhythm events, unplanned hospitalizations and death by 24%, or 22.7% versus 29.2% over about three years.
- The approach mixed potassium-rich foods, supplement tablets and, when needed, a potassium-sparing medication, with regular blood tests guiding the dose.
- Everyone studied was a high-risk defibrillator patient whose potassium was tracked by repeated blood tests, and nothing here shows that raising potassium helps people without those conditions.
References
- Jøns C, Zheng C, Winsløw UCG, et al. Increasing the Potassium Level in Patients at High Risk for Ventricular Arrhythmias. N Engl J Med. 2025;393(20):1979–1989. link