Opinions differ on certain foods and herbs, such as Brussels sprouts or coriander: What one likes, another does not like at all. But why is it like that? How do taste dislikes and preferences arise? Whether you taste something bitter can also have genetic causes.
The psychologist Kathrin Ohla knows what it’s like when you absolutely don’t like a food. “I always found Brussels sprouts unbearably bitter,” says the 44-year-old. But because she kept hearing what great ingredients it has, she started an experiment on herself: for a week she forced herself to eat Brussels sprouts every day to get used to the taste.
Because that is one of the many important findings of taste researchers like Kathrin Ohla from the University of Münster or Maik Behrens from the Leibniz Institute for Food Systems Biology in Freising: Taste preferences can change. But not whether one perceives broccoli and Brussels sprouts as very bitter: that is actually hereditary.
“There is a genetic reason for the recognition of certain bitter substances,” explains Behrens. The TAS2R38 gene is responsible for this: those in whom it is fully functional can taste certain bitter substances intensely. “That’s the case for most people,” says the biologist. However, about 30 percent of the population belong to the “non-tasters”.
For the taste “bitter” there is another special feature on the tongue: Because in the so-called papillae there are taste buds with 25 different receptor types. One or two are common for the other flavors, i.e. sweet, sour, salty and umami.
To the chagrin of the researchers, the opinion still persists that the taste receptors are arranged in very specific areas of the tongue – i.e. “sweet” at the front and “sour” and “salty” more towards the edges. “This card is actually nonsense,” says Ohla.
Rather, it is correct that the “little bumps” – i.e. papillae – are distributed over the entire tongue. There are a particularly large number of bitter receptors in the back of the tongue. That makes sense too, says the expert. Because if that area is stimulated, it also stimulates an extra nerve that can trigger gagging. A protective measure for our body in order to be able to spit out possible inedible or even toxic substances immediately after swallowing.
“Everything that activates the taste buds is passed on to the brain via nerve fibers. A taste impression is then formed,” explains Behrens. In general usage, there are many senses that are involved: “It’s not for nothing that people say the eye eats,” he says.
However, the odor that is absorbed retronasally is of even greater importance: i.e. from the oral cavity via the pharynx to the receptors in the nasal cavity. This is also the reason why you taste less good when you have a cold: “In fact, you just smell less,” the biologist clarifies.
However, it is wrong if one also associates “spicy” with a sense of taste. “It’s actually a stimulus at a nerve ending in the mouth, which also happens on the skin,” says Maik Behrens. So if you think something tastes hot, it’s not actually about tasting in the narrower sense. “Hot is not a taste, but a perception of pain or temperature,” says Ohla.
However, no matter how you put it, the fact is that while some people like some foods, others literally shake themselves. A good example of this is coriander: “Some say it tastes like soap, others find it very pleasant,” says the psychologist. In this case, however, it is not the receptors on the tongue that are primarily responsible, but a genetic variation in the sense of smell. Because it has numerous receptors and thus also ensures diversity in perceptions.
And the environment also has an influence on the sense of taste. “Socialization also plays a role in preferences,” explains Maik Behrens. “In Asian countries, for example, where coriander is used much more, there are far fewer rejecters than here.” It is conceivable that the acceptance of this spice plant will one day develop in a similar way to that of garlic. Because since people in Germany come into contact with it much sooner and more than before, they really appreciate this food component.
“You can get used to almost anything,” assures the scientist. “There comes psychology and overrides genetics.” Her own experiment with Brussels sprouts was also successful: “The first few days were really bad,” she looks back. “But now it’s one of my favorite vegetables.”
