Environmental Effects Exceed Genetic Effects on Perceived Intensity and Pleasantness of Several Odors: A Three-Population Twin Study

Abstract

Human genes encoding odorant receptors have been identified, but the contribution of genetic effects to total variation in specific odor perceptions is largely unknown. We estimated the relative contributions of genetic and environmental effects to variation in the perceived intensity and pleasantness of cinnamon, chocolate, turpentine, and isovaleric acid (sweaty) odors by quantitative genetic modeling of odor rating data from 856 twin individuals (including 83 complete monozygotic and 275 dizygotic twin pairs) aged 10-60 years (44% males and 56% females) from Australia, Denmark, and Finland. Results from fitting univariate models including components for additive genetic (A), shared environmental (C), and non-shared environmental (E) effects to the data implied that non-shared environmental effects account for the most variation in ratings of individual odors while genetic effects play only a minor role. Multivariate independent pathway model revealed a modest but significant common additive genetic component for intensity ratings, explaining 18% of the total variation. The results promote the importance of inter-individual variation in odor exposures and olfactory plasticity to odor perception.

The Role of Sweet Taste in Satiation and Satiety

“…Interestingly, the genetic variations of the GNAT3 gene also explained 13% of the variation in sweet taste perception [83]. Another study of female monozygotic and dizygotic twins reported that genetics accounts partly for the ability to perceive the intensity of a sweet (sucrose) solution and for the liking of sweet foods [84], suggesting that liking of sweet-tasting foods is a multifactorial, polygenic trait [85]. …”

Genetics of Taste and Smell

“…For instance, the ability to smell food odors like chocolate or lemon is associated with little or no heritability. 148,149 However, the pleasantness of cinnamon is heritable and has been mapped to chromosome 4 by linkage analysis. 150 If the allelic genes that determine the pleasantness of odors like cinnamon are identified, studies of genotype and food intake might be worthwhile.…”

The Rewarding Effect of Pictures with Positive Emotional Connotation upon Perception and Processing of Pleasant Odors—An FMRI Study

“…In order to investigate hedonic impressions elicited by olfactory stimuli, functional MRI has been used with increasing frequency during the last decade (Fulbright et al, 1998; Royet et al, 2000; Zatorre et al, 2000; Bensafi et al, 2002b; Jacob et al, 2003; Rolls et al, 2003; Konstantinidis et al, 2006; Grabenhorst et al, 2007; Knaapila et al, 2007, 2008; Lapid et al, 2008; Katata et al, 2009; Kermen et al, 2011). Olfactory-visual cross-modal phenomena may be approached by studying the effect of olfaction on visual cues, or vice versa, the effect of vision on olfactory processing, or by simultaneous presentation of both odors and images.…”