Genetic and Environmental Influences on Chemosensory Perception and Preferences

Chemosensory perceptions have biological relevance in aiding the recognition of nutrients and toxins, and initiating physiological processes that affect the digestion system. Food is first and foremost a source of nutrition affecting our well-being, but it is also characterized by one’s culture and is a great source of pleasure and satisfaction. Affective responses to sensory characteristics of foods are the best predictor of human food choice in the absence of economic and availability constraints. The aim of this work was to elucidate the impact of genes and environment on responses and preference for astringent, pungent (sensory ‘burn’ caused by spicy foods) and sour perceptions. Furthermore, a coherent picture of the chemosensory preferences and their underlying causes in young adulthood was achieved. Extensive data from 331 Finnish twins (21-25 years, 146 men, 185 women) were collected as part of FinnTwin12-study including pleasantness and intensity responses to samples spiked with sour, pungent, umami, and astringent stimuli (subgroup for astringency n=194, 96 men, 98 women). Liking and use-frequency responses for variety of food and beverage names representing these chemosensory qualities were collected. In addition, eating behavior related traits (e.g. food neophobia) were measured with validated scales. The heritabilities of chemosensory traits and food preferences were estimated. Furthermore, subgroups of respondents were identified based on preferences to sour, pungent and umami foods. Differences in food behavior and sensory responses, and the impact of genes were explored in the obtained subgroups. Sensory pleasantness and intensity responses to sourness and pungency showed modest heritabilities (12-31%) whereas astringency perception showed no inheritance. However, suggestive evidence that salivary secretion related to astringent stimulation is under genetic control was observed (heritability 43-51%). The preference for foods with sour and spicy flavor qualities showed a clearer and higher impact of genes (heritability 45-50%). Two subgroups of respondents were identified. The ‘basic’ group was less dramatic in their flavor preferences, whereas the ‘adventurous’ favored foods with sour and pungent qualities. The adventurous, were also less food neophobic and exhibited more tolerance for the sensory ‘burn’ caused by capsaicin compared to the basic subgroup. The influence of genes underlying the subgrouping was discovered (heritability 66%). Being adventurous was suggestively found to be in linkage with umami and sour coding taste receptor genes: TAS1R1 and PKD1L3, respectively. This is the first work to demonstrate the role of genetics and environment in perceptions and preference for astringent and pungent flavor qualities, and one of the few to study the heritability of sour taste. It was demonstrated that preference for sour and pungent flavors was partially inherited. Furthermore, two subgroups of individuals were found differing in their flavor preferences. Genetic variability together with food neophobic tendency partially explained these differences. Food neophobia and genetic differences may form a barrier through which individual flavor preferences are generated.