The Accuracy of Potassium Content on Food Labels in Canada

Background/Objectives: In 2017, the Canadian Government updated labeling requirements for prepackaged products to include potassium as a mandatory nutrient. Higher potassium intakes are beneficial in the general population, but for those with hyperkalemia, a lower potassium intake is recommended. Methods: The Canadian Food Inspection Agency (CFIA) collects food products and analyzes them to determine their potassium content. The authors requested data collected by the CFIA between January 2005 and November 2023 through an Access to Information request (A-2023-00410). Paired-sample two-sided t-tests were used to compare the difference between the labeled and analyzed potassium contents. Cohen's Kappa was also used to assess agreement between values. Results: Data were available for 406 food items, with 376 having a labeled and analyzed potassium value. The number of samples within each product type was not equally spread; 60% of samples (243/405) were considered dairy analogs-comprising either plant-based milk or cheese products. The mean difference between analyzed and labeled potassium content was statistically significant at 15 mg per serving (SD, 68 mg; 95% CI, 8-22 mg; p < 0.001). Cohen's Kappa suggested moderate agreement between labeled and analyzed values (κ = 0.376; 95% CI, 0.305-0.447; p < 0.001). A total of 271 (69.7%) products exceeded a ±10% difference, with 90 (23.9%) over-reporting potassium and 181 (48.1%) under-reporting potassium. Conclusions: The total number of products that were compliance-tested for potassium in Canada was relatively low and skewed disproportionately toward plant-based dairy analogs. Most products had labeled potassium values that differed from the lab-analyzed values, with a greater tendency to under-report vs. over-report potassium content. This suggests that at least some labels may not be accurate enough to correctly identify high-potassium foods for those who are following a low-potassium diet.