Roxana Daneshjou
medical student
Stanford University

Supernova, ME, US

There are certain kinds of food that I like and some that I dislike, just like everybody else. But from an evolutionary standpoint, it seems like we shouldn't be turning our noses up at anything that helps us survive, nor should we have differing tastes than other people living in the same environment. Why would we develop a distaste for certain foods?

Roxana Daneshjou
HHMI medical fellow,
medical student,
School of Medicine,
Stanford University
Both genetics and the environment influence our preference for what we do and do not like.

Since your question has to do with evolution, let’s focus on what genetic studies have determined about how we taste our food. In school, we’re taught that taste buds can distinguish bitter, sweet, salty, sour, and umami (savory) flavors. However, evidence indicates that another modality of taste—the “fat” taste—exists in other mammals and may also exist in humans. Some of the genes responsible for these different taste modalities have been discovered, and it’s believed that differences in these genes may influence individual food preferences. In terms of evolution, one has to keep in mind that evolutionary change occurs over many generations. Thus, our taste buds may have evolved based on environmental pressures that are no longer an issue, leading to taste preferences that may not make sense in the modern world.

For instance, bitter taste is believed to have evolved as a protection against the consumption of poisonous plants. However, many plant-based foods that are good for us, such as broccoli, stimulate the same receptors, leading to a perception of bitter taste and disgust. There are varying degrees of how bitter someone perceives a food to be, of course, and this too, is influenced by genetics. Genetic differences have been linked to the ability to perceive the bitterness of phenylthiocarbamide (PTC), a nonfood chemical that is used to determine how sensitive someone is to bitterness. Different populations have different levels of sensitivity to PTC. For example, only 3% of West Africans do not perceive PTC as bitter, while about 30% of Caucasians do not perceive it as bitter. In a society where people don’t worry so much about eating the wrong plants, being overly sensitive to bitterness could lead to an avoidance of healthy vegetables.

Similarly, sour taste is also thought to serve as a protective mechanism. Most animals reject incredibly sour tastes. It is thought that the perception of sourness protects against eating spoiled food or unripe fruit. The genetic variability in the perception of sourness among the population is not well understood.

On the other hand, many of us really like sweet foods, and the evolutionary pressure behind this preference makes sense. Sweet foods are usually high in energy, and our prehistoric ancestors would need to eat high-calorie meals to survive a mobile lifestyle and the scarcity of food. There is variation in how drawn an individual is to sweet foods, which could be related to exactly what evolutionary pressures an individual’s ancestors faced (famine vs. plenty). Umami food—that is, food with a savory, meaty taste—is another type of food that people are attracted to. Molecularly, the processing of sweet foods and savory foods is thought to be similar or related. The genetic variability in umami preference has not been fully investigated; however, the attraction to umami foods is also likely to be related to the need for a high-calorie diet. A lot of recent research in mice indicates the presence of a taste for fat. A receptor called CD36 appears to mediate this taste in mice. Humans have a genetic variation in the CD36 sequence, but it is not known how this variation affects the taste of fat. However, the ability to be attracted to fatty foods makes sense, since, once again, it would allow our ancestors to be drawn to high-calorie foods.

While the aforementioned tastes have an environmental component as well, the perception of salty foods is thought to be largely influenced by environmental factors. This is interesting because Americans have a lot of salt in their diet (just look at the sodium levels in a can of soup or in fast food!), yet I don’t think most perceive their food as too salty.

Overall, environmental and genetic factors determine what you do and don’t like. But it appears we evolved for a world very different from our own, and so we seem to prefer high-calorie foods (despite an epidemic of obesity in this country) and we reject some healthy foods (because of their similar taste to some dangerous foods).

The information to answer your question came from the following review article:

Garcia-Bailo, B, et al. Genetic variation in taste and its influence on food selection. OMICS, 2009. 13(1): 69–80.

01/04/12 04:19