Both too little and too much potassium in the body can be dangerous to your cat's health. However, detecting an imbalance alone is not enough to justify starting supplementation. Diagnostic tests should first be performed, such as blood tests (electrolytes and kidney parameters, and sometimes hormone levels) or an ECG. Appropriate products can then be introduced as recommended by a veterinarian. This article focuses on diseases associated with hypokalemia, meaning a low potassium concentration in the blood.
Potassium deficiency — when can it occur?
Potassium deficiency is frequently discussed in the context of a homemade BARF diet. This is because a diet that is not properly balanced for potassium may cause kidney dysfunction. Knowing that meat and organ meats are the main sources of potassium is not enough, because the final potassium content of a prepared diet can vary depending on the types of meat and organs used, the proportions of the individual ingredients, and the supplements added. The sodium-to-potassium ratio is particularly important. Potassium deficiency is not always caused by a poorly formulated diet. It may also result from increased urinary loss of this electrolyte (for example, in chronic kidney disease) or from chronic diarrhea or vomiting. Hypokalemia is also common when a cat eats too little overall, for example because of anorexia, stress, or gastrointestinal disease. Incorrectly calculating a supplement dose is dangerous as well. Potassium citrate, potassium gluconate, or potassium chloride is generally used to supplement the diet. The amounts of the other electrolytes must also be taken into account, and the exact amount of pure elemental potassium in the chosen product must be calculated (1 g of potassium gluconate is not the same as 1 g of potassium itself). Cats with kidney disease should receive supplements while their blood potassium concentration is monitored regularly.
Hypokalemic polymyopathy
Hypokalemic polymyopathy is a common consequence of potassium deficiency. Affected cats show generalized weakness, stiffness, and skeletal muscle pain. As a result, they may be reluctant to jump onto raised surfaces or move around. Ventroflexion of the neck is another characteristic sign. Severe disease may lead to respiratory muscle paralysis. Causes include not only inadequate dietary potassium, but also hyperthyroidism, hyperaldosteronism, chronic diarrhea or vomiting, excessive fluid administration, and potassium-wasting diuretics. It most often develops secondary to chronic kidney disease, when the animal loses large amounts of potassium in the urine.
Hypokalemic nephropathy
If potassium deficiency persists for a prolonged period, renal tubular dysfunction and even changes in kidney tissue may develop. Tubulointerstitial nephritis and impaired kidney function (hypokalemic nephropathy) can occur, often in association with a diet containing urinary acidifiers.
Low potassium = heart problems?
Potassium is an electrolyte essential for normal heart muscle activity. Potassium deficiency has been associated with ECG changes indicating abnormal heart rhythms.
Potassium also supports digestive function
As mentioned earlier, potassium is essential for normal muscle function. In addition to skeletal and cardiac muscle, it also affects the smooth muscle found in the digestive tract. A potassium concentration that is too low may therefore lead to reduced intestinal motility and resulting constipation, a poorer appetite, and generalized weakness.
As we can see, an improperly balanced diet is not the only cause of potassium deficiency. Nevertheless, diet is a very important factor in maintaining electrolyte and acid-base balance and supporting normal muscular function.
Sources
- DiBartola, S. P. (2001). Management of hypokalaemia and hyperkalaemia. Journal of Feline Medicine and Surgery, 3(4), 181–183. https://doi.org/10.1053/jfms.2001.0147
- Dow, S. W., LeCouteur, R. A., Fettman, M. J., & Spurgeon, T. L. (1987). Potassium depletion in cats: Hypokalemic polymyopathy. Journal of the American Veterinary Medical Association, 191(12), 1563–1568. https://doi.org/10.2460/javma.1987.191.12.1563
- Dow, S. W., Fettman, M. J., Smith, K. R., Hamar, D. W., Nagode, L. A., Refsal, K. R., & Wilke, W. L. (1990). Effects of dietary acidification and potassium depletion on acid-base balance, mineral metabolism and renal function in adult cats. The Journal of Nutrition, 120(6), 569–578. https://doi.org/10.1093/jn/120.6.569
- Williamson, B. (2026). Feline hypokalemic polymyopathy. MSD Veterinary Manual. Merck & Co., Inc.