Use of potassium additives in processed foods is growing and its bioavailability exceeds that of potassium in produce and meats, a recent review warns. Teaching patients with chronic kidney disease (CKD) about potassium additives and a low potassium diet has become as important as teaching them about phosphorus.

“Clinicians and patients need to be aware of these changes in the food source to ensure potassium diet teaching is effective and safe,” author Kelly Picard, BSC, RD, stated in the Journal of Renal Nutrition.

Unfortunately, very little is known about the amounts of potassium additives in individual foods, she explained. Unlike low phosphorus dietary teaching, bioavailability quotients do not exist in hyperkalemia guidelines.

To reduce sodium in processed foods, some manufacturers have replaced sodium additives with potassium additives. In a study by Parpia et al. (J Ren Nutr 2018;28:83-90), 1 of every 11 foods commonly eaten by Canadian dialysis patients contained potassium additives. Potassium additives foods had 900 mg/100 g.

“Nine hundred milligram per 100 g is very high in potassium compared with the referenced standard and means high-potassium may be found in nontraditional food sources,” according to Picard. “Patients and clinicians looking to avoid high potassium need to be aware of these food products and know how to identify them to avoid causing hyperkalemia.”

Based on data from the Dietary Approaches to Stop Hypertension trial and similar studies, the potassium bioavailability of whole fruits and vegetables may be as low as 50% to 60%. Including more fruits and vegetables in a CKD patient’s diet may improve their blood pressure and metabolic acidosis and decrease the risk for kidney injury, without increasing serum potassium levels substantially, Picard suggested. She added that lowering potassium intake requires the assistance of a renal dietitian, who can balance multiple dietary restrictions with adequate nutrition.

Clinicians also need to consider the potassium content of medications, according to J. Keith Fisher, MD, who reviewed a recent article on hyperkalemia. Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, some diuretics, cyclosporine, trimethoprim, angiotensin inhibitors, beta-blockers, calcium blockers, succinylcholine, digoxin, heparin, and mannitol may cause high potassium levels.

References

Picard K. Potassium additives and bioavailability: Are we missing something in hyperkalemia management? J Ren Nutr.

Stinson A. What to know about high potassium. Medical News Today; last reviewed April 8, 2019.