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Artichokes and absinthe Not everyone experiences bitter taste right away
One feels the taste of artichoke as very bitter - another, not at all. For other bitter substances, eg. Absinthe, on the other hand, no individual perceptual differences can be observed. But how can this phenomenon be explained? A German-American research team has now investigated how differences in taste experience come about.
Recognition of the flavor "bitter" is intended to protect against poisonous food
The example artichoke shows it vividly: Bitter foods are not always poisonous. Nevertheless, science assumes that the recognition of a bitter taste should generally protect against the consumption of poisonous or spoiled food. However, the ability to recognize bitter substances, according to a statement of the German Institute for Nutritional Research (DIfE) apparently vary widely from person to person. As scientists from the German Institute for Nutritional Research (DIfE) and the University of California were able to show for the first time, this can apparently be attributed to the chromosomal distribution of the bitter receptor gene variants.
Bitter taste is subjective. Image: M.studio - fotolia This is shown by the example of the perception of the artificial substance "phenylthiocarbamide", because for these there are "tasters" and "non-smokers". Which group someone belongs to depends on whether or not they have the intact gene variant of the bitter receptor TAS2R38 or not.
Perceptual differences, for which a change in the genetic material (mutation) is responsible in only a single bitter receptor gene, however, are very rare. In most cases, instead, several of the 25 different bitter receptors would recognize a bitter substance at the same time - albeit sometimes in different degrees.
Scientists examine 48 study participants
In the journal "PLOS Genetics", the research team led by Wolfgang Meyerhof and Natacha Roudnitzky from the DIfE continue to report on the different perceptions of the bitter substances Grosheimin and Absinthin. While the former is contained among others in the artichoke, absinthe is the bitter substance from the dark green or blue oil of wormwood, which is also used for the flavoring of alcoholic beverages.
The researchers had performed genetic and sensory studies in 48 study participants. They recognized that individual differences in taste perception also depend on the distribution of receptor gene variants on the chromosomes. Because in most cases these would not be inherited individually, but in groups, which would lead to some substances, such. Grosheimin are often perceived as having varying degrees of bitter - other bitter substances such as Absinthin, however, not.
25% probability for two chromosomes with insensitive receptor genes
Because Grosheimin is mainly recognized by two different bitter receptors (TAS2R43 and TAS2R46), whereby the genes for these two on a chromosome are close together and therefore usually inherited together. The chromosome has "either two sensitive or two for the bitter substance insensitive gene variants on," the release of the DifE on. Since each person has a double set of chromosomes (one each from mother and father), there is an approximately 25 percent chance that a child will inherit two chromosomes with insensitive receptor genes. As a consequence, this child can only taste Grosheimin in very high concentrations with the help of other receptors, while another child with two sensitive variants already recognizes the bitter substances in a very low dose.
For Absinthin, at least one sensitive receptor is always inherited
The situation is different with Absinthin. Although there are also two specific receptors (TAS2R30 and TAS2R46) whose genes are close to each other, there is another distribution of the variants. Because here on a chromosome either a sensitive variant of the one and an insensitive variant of the other receptor or vice versa. Accordingly, in this case, a child always inherits at least one sensitive receptor capable of identifying absinthe. Therefore, there are no differences in perception here as in the artichoke - instead, the scene drink absinthe, for example. felt by most people as bitter.
"As our results show, the genes affect our taste perception not insignificant. In addition, they prove that the genetic mechanisms that influence the perception of bitter substances are much more complex than originally assumed, "says first author Natacha Roudnitzky. The aim now is to gain further insights into the biological basis of taste perception "in order to better understand how they influence our food choices and our dietary habits in addition to other senses and cultural habits", adds the head of the Molecular Genetics Department at DifE, Wolfgang Meyerhof. (No)