Sweetness drives brain level amplification of saltiness offering a new pathway to salt reduction

Excessive sodium intake is associated with various health risks, whereas reducing salt content in foods often leads to weakened saltiness perception and decreased consumer acceptance. Taste-taste interactions provide a promising strategy for salt reduction; however, the central neural mechanisms underlying sweet-salty synergy remain insufficiently understood. In this study, sensory evaluation combined with electroencephalography (EEG) was used to investigate the effect of sucrose on saltiness perception and the corresponding cortical responses. Sixty participants evaluated a series of sucrose-sodium chloride mixed solutions, in which NaCl concentration was fixed at 6.84 mM and sucrose concentration was varied across seven gradients. Sensory results showed that sucrose enhanced saltiness perception in a concentration-dependent manner, exhibiting an inverted U-shaped trend, with the strongest saltiness enhancement observed at 14.1-15 mM sucrose. EEG power spectral density and area-under-the-curve analyses further revealed that FP1, Pz, and O2 were the most responsive electrode sites during sweet-salty stimulation, suggesting the involvement of frontal, parietal, and occipital regions in cross-modal taste processing. Among the analyzed frequency bands, δ (1-4 Hz) and θ (4-8 Hz) activities were more sensitive to sucrose-salt mixtures, indicating enhanced early sensory encoding, attentional allocation, and multisensory integration. In addition, a prominent response around 6 Hz was observed in frontal and occipital regions under the optimal sucrose-salt condition, further supporting the role of low-frequency synchronization in sweet-salty flavor integration. These findings demonstrate that sucrose can effectively enhance saltiness perception within an appropriate concentration range and that EEG provides an objective approach for characterizing the neural dynamics of taste interaction. This study offers neurophysiological evidence for "salt reduction without saltiness loss" and provides theoretical support for the development of reduced-sodium foods and high-palatability flavor formulations.