The Truth About Your Taste Buds: A Conversation with a Monell Chemist
Summary
For decades, we’ve been taught that our tongue has a distinct map that separates sweetness at the front, bitterness at the back, and sourness and saltiness at the sides. However, this is a myth. Our taste buds are located all over the tongue and respond to varying degrees of tastes. In this Q&A, we spoke with Dr. Robert Margolsky of Monell Chemical Census Center to discover how taste buds work, what happens when they get injured, and how our genes influence our preferences for certain tastes. We also delve into how animals’ taste receptors differ and explore the links between taste and evolution.
Table of Contents
- The Myth of the Taste Map
- How Taste Buds Work
- The Role of Taste in Biological Systems
- Super Tasters and Non-Tasters
- Adapting to Bitter Tastes
- The Cilantro Controversy
- Taste Evolution and Animal Adaptations
- Improving Human Health Through Taste
The Myth of the Taste Map
The notion that our tongue has a distinct map with separate sections responsible for taste is incorrect. Dr. Margolsky explains that the taste map arose from a German researcher’s psychological studies on the sensitivity of human subjects to different taste qualities such as sweet, sour, salty, and bitter. This sensitivity is not even throughout the tongue- least at the center of the tongue and most sensitive right around the edge. There are small differences in sensitivity to different taste qualities, with more sensitivity to sweet at the front and more sensitivity to bitter at the back. However, this has been exaggerated into a more extreme version of the taste map that is wholly incorrect.
How Taste Buds Work
Each taste bud has specialized taste receptor cells that respond to different taste qualities. There are 50 to 100 receptor cells in each bump-like taste bud, and they respond to sweet, sour, salty, bitter, and umami (amino acid taste). Some cells respond to multiple taste qualities, while others are narrowly defined. When we taste things, it can trigger salivation, signaling to the stomach to prepare to receive food.
The Role of Taste in Biological Systems
The taste system has several crucial roles in our lives, such as acting as a decision point for deciding whether food is good or poisonous. The system detects bad things in our environment and helps avoid eating poisonous plants. On the other hand, anticipating certain foods and digesting them better gives an evolutionary advantage.
Super Tasters and Non-Tasters
Some people are more sensitive to all types of taste qualities, with bitter compounds being the most evident. This phenotype is known as the super taster, while the flip side is the non-taster. Super tasters can hardly detect chemical compounds such as those in broccoli or Brussels sprouts. Conversely, non-tasters do not have that particular receptor that responds to cilantro, making it unpleasant to them.
Adapting to Bitter Tastes
Young children tend to be more sensitive to bitter than adults, but with time, one can learn to associate bitterness with positive effects such as alcohol buzz or psychological activity. For example, those that like beer can associate their bitterness with a pleasant psychological effect.
The Cilantro Controversy
The cilantro taste fascination is genetic. People who like cilantro have a particular receptor version, while those who hate it have a different receptor that detects it as nasty or unpleasant. Taste plays a significant evolutionary role in detecting bad things in the environment and finding the best source of protein.
Taste Evolution and Animal Adaptations
Cats, for instance, live off a protein diet and do not eat plants. They do not need to detect a sweet ripe fruit but need to find the best protein source. Cats cannot taste sweet, and when they like a particular food, it’s because of the amino acid umami component or fat, contrary to humans who associate sweetness with pleasant psychological effects.
Improving Human Health Through Taste
Humans evolved under conditions that made it hard to find ripe fruit or nutritious sources, leading to overeating and a preference for calorie-rich sugary foods. Scientists aim to change people’s set points from high sugar, high calories to moderate levels of calories to reduce obesity and diabetes prevalence.
Conclusion
Taste buds play a vital role in our survival, selectively detecting food items that are either nutritious or poisonous. The taste map myth has misled us into thinking that there are distinct sections responsible for taste. However, taste buds are located all over the tongue and respond to different degrees of taste qualities. Understanding taste can help improve human health by changing our preference set points to avoid calorie-rich sugary foods. Taste also plays an evolutionary role in animals, helping them detect bad things in the environment and find the best protein sources.
