Potassium

What is potassium?

Potassium (K) occurs mainly as a positively charged ion in the body. It contributes to the electrical activity of nerves and muscles. Food sources include potatoes, pulses, vegetables, fruit and dairy products. [2]

The word “electrolytes” does not describe a complete formulation. Assessing a product requires the individual minerals and their amounts. A sodium–potassium mixture is not automatically comparable with potassium alone.

Potassium, potassium chloride and quantities

Potassium chloride and potassium citrate are compounds. For dietary accounting, use the declared amount of potassium rather than the mass of the whole compound. Check whether a quantity refers to one capsule, a serving or the daily portion.

A simple label example: if one serving supplies 200 mg potassium, two servings supply 400 mg. This calculation does not establish a need for that extra amount. Food and any other preparations belong in the same intake assessment.

Which question does a study answer?

A blood-pressure reading, stroke incidence and crop yield are different outcomes. A change in one does not establish an effect on the others. It also matters whether a study changes potassium alone or reduces sodium at the same time.

The following sections therefore separate dietary reference values, clinical studies and plant research. Population, comparator and intervention help explain how each finding can be used.

How much potassium does EFSA recommend?

EFSA sets an adequate intake (AI), rather than an exactly determined individual requirement. All values refer to total daily intake. [1]

Who may need a closer look?

A limited or repetitive diet warrants a review of regular food sources. A potassium preparation does not replace this assessment. A short dietary record, product list and medication list can make a clinical discussion more useful than a presumed deficiency symptom alone.

In 2025, WHO conditionally recommended replacing regular table salt with lower-sodium, potassium-containing substitutes when choosing to use salt. It applies to adults, excluding pregnant women, children and people with impaired potassium excretion. It forms part of a sodium-reduction strategy. [6]

What do the studies show?

When extra potassium can be problematic

EFSA could not derive a tolerable upper intake level (UL) for potassium. The absence of a limit does not establish that unlimited amounts are safe. [7]

Kidney disease, ACE inhibitors, angiotensin receptor blockers and potassium-sparing diuretics can reduce potassium excretion. Excessively high blood potassium can cause dangerous heart-rhythm disturbances. Other diuretics increase potassium losses instead. [2]

With these conditions or medicines, discuss additional preparations and potassium-containing salt substitutes with the treating clinician first. Review the full combination, including products bought without prescription. Do not change prescribed medication because of a knowledge article.

Water balance and transport

Potassium contributes to stomatal regulation, osmotic balance and assimilate transport. The review by Wang and colleagues describes its role under drought and salt stress, among other conditions. [8]

A physiological role does not establish a universal yield benefit from extra fertilisation. Under stress, distinguish an actual nutrient shortfall from limited water availability and other causes.

What Swiss long-term research shows

From analysis to an appropriate amount

Swiss GRUD guidance places fertilisation in its crop and site context. Soil analysis, existing supply and nutrient removal inform professional planning. A laboratory result needs to be read alongside its sampling procedure and analytical method. [10]

Labels may state potassium (K) or potassium-oxide equivalents (K₂O). These quantities differ: 1 kg K₂O corresponds to approximately 0.83 kg K. This conversion describes a labelling convention, not the chemical form present in soil.

Worked example: one kilogram of a fertiliser labelled 20% K₂O supplies 200 g of K₂O equivalent, or approximately 166 g K. The fertilisation plan must first establish whether and how much to apply. Amounts per hectare, amounts per plant and irrigation-water concentrations must not be mixed.