Sodium density, a new approach to assess salt in packaged foods.

Packaged foods are a major source of dietary sodium worldwide. Nutrition labels often report sodium content in milligrams and a percent daily value; however, these measures are not sufficiently intuitive for comparing sodium content across packaged foods. We propose a new way to use sodium density (mg/kcal) in a serving to bypass nutrition label units. Because the WHO recommended sodium limit for adults (2000 mg/day) and the reference energy intake used on nutrition labels (2000 kcal/day) are numerically identical, a sodium-to-calorie ratio of 1 mg/kcal could serve as a practical guidepost to compare sodium content and support packaged food selection, rather than to provide an individual-level recommendation for daily sodium intake. Sodium density, applied to food log entries, could help consumers identify lower-sodium options among packaged foods, support healthcare professionals in nutrition education design personalized strategies to reduce sodium consumption, and inform developments of nutrition dashboards and AI-driven tracking tools.