Review highlights genetic variations in sweet taste (Flavour and Fragrance Journal)
 
3rd June 2011
Nathan Gray
 
Better understanding of the genetic factors behind the considerable variation in sweet taste perception and preferences may help to create foods that are better accepted by consumers, say scientists.  The new review, published in Flavour and Fragrance Journal and funded by grants from the US National Institute for Health (NIH) and the Ajinomoto Amino Acid Research Program, highlights that although learning mechanisms contribute to variations in sweet taste, much of our difference in preference is genetically determined.  “Our ongoing studies using the mouse model demonstrate that a significant portion of variation in sweetener preferences depends on genes that are not involved in peripheral taste processing. These genes are likely involved in central mechanisms of sweet taste processing, reward and/or motivation,” said the reviews, led by Dr Alexander Bachmanov from the Monell Chemical Senses Center, USA.  “The data presented in this review demonstrate that sweet taste has a complex genetic architecture.
 
Variation of the sweet taste receptor genes contributes to differences in sweet taste perception within and between species,” they added.  The authors added that the review illustrates the complex genetics of sweet taste preferences and its impact on human nutrition and health. However, they explained that by identifying genes responsible for within- and between-species variation in sweet taste, research can “provide tools to better control food acceptance in humans and other animals.”
 
Sweet taste
Dr. Bachmanov and his colleagues explained that the sense of taste “has probably evolved to allow animals to choose and consume appropriate food.”   For example, the authors said that “sugars are important nutrients for animals from many different species ranging from insects to mammals. In animals from many species, sugars are recognized by the taste system and evoke appetitive consummatory responses.”   They noted that in addition to sugars, a wide range of other chemicals (such as sweeteners), also evoke the sensation of sweetness in humans and are palatable to many other animals.  As such, Bachmanov and his team said that sweet taste “is a powerful factor influencing food acceptance.”
 
The reviews said that although appetite responses to sweet taste stimuli are inborn in many animals, “they are also often modulated by environment and depend on genetic factors.”   “The interactive mechanisms of sweet taste suggest that it is a part of a complex ingestive behaviour and is likely to be determined by multiple genes,” they said
 
Review details
Bachmanov and his colleagues noted several examples of differences in sweet taste preferences among species of vertebrate animals, adding that many mammals differ in preferences for artificial sweeteners.  “Despite nearly universal preference for sugars, the chicken and Felidae species (domestic cat, tiger, lion and cheetah) are not attracted to sugars and other sweeteners,” they said.  They reported that variation in the T1R (sweet taste) receptors plays an important role in these differences in sweet taste preferences.
 
The review also noted that humans differ in their perception of sweet taste: “One of the best known examples of this variation is a sweet liking phenotype: in ‘sweet-likers’, hedonic ratings of sucrose solutions monotonously increase with increasing concentrations, while in ‘sweet-dislikers’ at higher sucrose concentrations the ratings decrease,” said Bachmanov and his co-workers.  They said the mechanisms underlying this variation inhuman sweet taste, including ‘sweet-liker’ and ‘sweet-disliker’ phenotype “could be complex” and may involve peripheral or central taste processing, could be genetically determined and acquired, or could depend on interaction between genetic and environmental factors.  “Nevertheless, genetic factors explain at least part of variation in sweet taste preferences in humans,” they said.
 
Source: Flavour and Fragrance Journal, Published online ahead of print, doi: 10.1002/ffj.2074
Genetics of sweet taste preferences
Authors: A.A Bachmanov, N.P Bosak, W.B. Floriano, M.Inoue, et al