In life, one way or the other, you have probably eaten broccoli. After all, broccoli a superfood! One cup is chock-full of antioxidants, vitamins, minerals, and fiber.
But, do you like broccoli? Do your eyes convey the same longing as Louie when viewing this cruciferous vegetable? The answer behind why you like broccoli –or force it down– is rooted in science: the science behind acquired taste!
HUMAN TASTE PERCEPTION
The great range in human taste perception between people makes taste unique among the senses! Sensitivities of vision, hearing, touch, and smell vary too, though only modestly from person to person. To survive, our ancestors needed to live in basically the same sensory world as today. We’re all fragile, warm-blooded bodies, after all.
Olfaction gets a protective nod, without question. While olfaction is specialized in the detection of volatile chemicals around us, taste is restricted to the detection of contact-chemicals.
The tongue acts as one of our gatekeepers by helping us distinguish between good and noxious substances and consequently guiding our food choices.
TASTE AND SMELL
Through the process of evolution, the perception of taste (along with smell) provides humans with a dietary advantage. Today, taste may indicate whether a particular food is corrupted and potentially harmful for consumption.
Kevin (below) will survive to tape another episode of The Office!
Smell is key and intertwined with taste, but exploring these interrelated senses would make this post WAY too long.
THE SCIENCE BEHIND ACQUIRED TASTE
‘Gustatory chemosensory perception’ is a mouthful! This means discerning taste stimuli. (stimuli = food and drink)
Taste chemically tests everything that enters our mouths. That’s why taste was molded by what our ancestors consumed over the eons.
Taste doesn’t live in one sensory world!
This is especially true of the taste we call bitter.
BITTER FLAVOR RECEPTORS
The bitter taste receptor has been found and named TAS2R38. It’s located on chromosome # 8, but not everyone has this gene!
Taste is not universal!
What an interesting fact! This seems intuitive, but this notion was not conclusively proven until the 1930s.
Taste is an inherited trait, proved by Augustinian monk Gregor Mendel. Inherent traits range from flower colors all the way to baldness!
TASTERS AND NON TASTERS
Initially, there were ‘tasters’ of the bitter gene and ‘non-tasters.’ With human spread across our globe, different habitats and climates led to different food choices. Survival challenges grew the division between tasters and non-tasters.
Depending on where populations migrated to factored into how this gene evolved.
Not all bitter compounds are poison. Willow bark has a bitter compound, salicin. Salicin, the precursor of aspirin, is useful as an analgesic, anti-inflammatory agent, and antipyretic. (Lots of As!)
Some forms of bitter insensitivity enhance survival, too!
COFFEE AND CHOCOLATE!
The reason coffee is ‘an acquired taste’ is that coffee has several bitter compounds. Most notable is caffeine! (more on the science of coffee and caffeine here!)
Raw coffee beans don’t have much taste. Roasting the beans is what teases out the bitter flavors. It’s a delicate process, so finding a balance is key.
Cocoa beans are the opposite. Raw, they’re quite bitter. They have different flavor profiles, depending on where they’re grown, dried, and fermented. Hence the vast array of different chocolate flavors!
One of our ancestors stuck with it though. Maybe someone without the bitter gene!
BITTER RECEPTORS WARD OFF INFECTIONS
I think you’ll all agree that sweetness is a powerful motivator!
Sugars are the foundation of the earth’s food chain. Made by plants during photosynthesis, sugar molecules contain the sun’s energy.
Because sugars are so useful, it’s rare to find them in concentrated forms within nature. Nature spread the wealth! Hence, most animals don’t need concentrated sugar. Including us!
(You won’t find any of the desserts below hanging from a plant!)
OK, yes, I ate the missing cinnamon roll.
We’re dependent on sugar for our big brains to use as fuel. Maybe this rationale is why our sweet receptors (T1R3 combined with T1R2 ) can recognize all kinds of sweet substances including natural sugars, artificial sweeteners, and D-amino acids.
This, it turns out, has backfired.
When you take the sugar out of its natural sources (fruits, for example) you are missing out of a multitude of fibers, vitamins, enzymes, and antioxidants that help to balance the sugar intake, and provide health benefits. You made a drug! Congrats!
Sugarcane, the world’s primary source of refined sugar for thousands of years, needs a warm climate to proliferate. Since it is easy to transport without spoiling, sugar traveled along with man in their great migration.
Called white gold by British colonists, sugar’s monetary value remains today. Sugarcane is the world’s third most valuable crop.
Dating over 2500 years ago there were parables about the Buddha enjoying sweet treats.
Twelfth century theologian Thomas Aquinas must have had quite a sweet tooth. He wrote that eating sugar would not break a religious fast because sugar was a medicine.
Medicine for our dopamine receptors!
SWEET RECEPTORS AND DOPAMINE
Studies have shown a link between sugar and dopamine. Dopamine is famous! Dopamine is a chemical that ferries information between neurons.
This chemical plays a role in how we feel pleasure and happiness. Dopamine is a big part of our unique human ability to think and plan: it helps us strive, focus, and find things interesting.
When we eat sugar, the sugar molecule locks onto the dopamine receptors. Dopamine is released, reminding us that we feel good.
This is a perfect example of the phrase too much of a good thing can <whatever the end of the phrase is.>
I’m not going to preach to you about the evils of excessive sugar consumption and how it wreaks havoc on our bodies, including teeth. Moving on…
In retrospect, this makes a lot of sense. Our umami taste receptors are urging us to seek out these essential foods. In case you’re wondering, here’s a short list….
Salt taste receptors and how they affect us is the least understood of the five taste receptors! This seems strange, considering that salt is, well, salt. NaCl.
Salt receptors are divided into two types, based solely on salt concentration. Salt concentration? That’s interesting.
As late as 2016, using poor mice again, scientists discovered that salt receptors are subdivided into two separate populations, based on the size of the salt molecules we ingest.
The reason we have two types of salt receptors is –clearly– to keep us from eating too much.
In 2019, a study using healthy adults showed that subjects who were less sensitive to salty taste reported consuming more bakery and salty baked products, saturated-fat-rich products, and soft drinks than hypersensitive subjects. (OUCH!)
Sour taste detection functions as an important sensory input to warn against the ingestion of acidic food sources,(more here) meaning, unripe and spoiled.
It would follow that scavengers, also known as carrion eaters, don’t have this receptor!
THE FIVE TASTE RECEPTOR TYPES ARE NOT JUST ON THE TONGUE
The receptors for bitter, sweet, and umami are not limited to the tongue!
These receptors are also found in the intestines, stomach, pancreas, respiratory tract, and even sperm! (This can be cited in many articles but here’s one for you.)
Pathogens, tumors, and allergens are detected with great sensitivity and specificity by the immune system. Considered a sixth sense by some, the immune system is a means to signal and mobilize the body’s response to invasion.
Understanding how and why the immune and nervous systems communicate in a bidirectional pathway has been fundamental to the development of the psychoneuroimmunology (PNI) field. Taste is a big part of self-regulation!
THE SCIENCE BEHIND ACQUIRED TASTE
As I’m sure you already concluded, our diet plays a big role in our taste receptors working the way they were meant to!
It is remarkable that food quality and intensity can be coded by just 5 basic tastes! And our individual coding is the backbone behind the science of acquired taste.
The science behind acquired taste is far more complex than I realized. (Which is why there are so many article links in this post!)
THE WHY BEHIND OUR FOOD CHOICES
Biochemists, anthropologists, and neuroscientists will continue to explore how we perceive taste. Chefs, agriculture and food technologists, and behavioral psychologists make contributions to the whys behind the flavor of foods as well.
One thing is certain; taste perception is as individual as we are!