Deprivation of visual stimuli increases sensitivity to sweet taste in a Vietnamese Kinh population

Temporal visual deprivation increased sweet but not other basic tastes’ sensitivity in a Central European population as shown recently (Leszkowicz et al., 2023). We aimed to investigate whether this is a more general trait independent of ethnicity, or specific to a geographic region. We, therefore, assessed taste recognition thresholds for basic tastes: sweet, bitter, salty, sour, and umami, in a Southeast Asian population, and more specifically in the Vietnamese. The thresholds were measured in two conditions: when participants had their eyes open, and when blindfolded. Participants recognized sweet taste at a lower recognition threshold (lower sucrose concentration) when they were blindfolded than when their eyes were open (2.76 g/l and 3.80 g/l of sucrose, respectively, p = 0.024). Only sweet taste was sensitive to temporal visual deprivation; recognition thresholds for bitter, salty, sour and umami did not differ between the two experimental conditions. These results are consistent with those obtained previously in the Central European population, which suggests that the sensitivity of sweet taste – and only sweet taste out of the five basic taste modalities – to temporal visual deprivation could be a general trait independent of a geographic region and ethnicity. Our results suggest that a visual component could have a different share of the coding of different taste modalities in taste-responsive brain regions.