The Sodium Priority Hypothesis: A Taste-Nutrition Framework Linking Salt Taste, Umami and Food Acceptance

Taste supports survival by helping animals identify useful nutrients and avoid harmful excess. Sodium is essential for extracellular fluid balance, osmotic regulation, nerve transmission, muscle contraction, and nutrient transport, but it is continually lost and must be replaced through diet. This review proposes the Sodium Priority Hypothesis: sodium is a primary nutritional target whose consumption is enabled by converging sensory mechanisms. Sodium chloride provides the dominant route to pure saltiness, while sodium-linked umami, bitterness suppression, and taste-mixture modulation may further support sodium acquisition and food acceptance. Potassium provides an important contrast because it is essential but has weaker salty quality, bitter or metallic side notes, and does not reproduce sodium’s bitterness-suppressing effect in model savory systems. By linking sodium detection, sodium-linked umami, bitterness suppression, and food-mixture modulation with appetite and potential pre-ingestive or post-ingestive regulation, the hypothesis extends the taste-nutrition interface to sodium acquisition. The hypothesis does not reject umami as a protein-related signal, but proposes that sodium-linked umami may have dual relevance for protein food recognition and sodium acquisition. This framework generates testable predictions and may inform sodium reduction, food reformulation, and dietary guidance.