Tag Archives: #taste

Cancer Survivors’ Tongues Less Sensitive To Tastes Than Those of Healthy Peers (Medicine)

Most survivors of squamous cell head and neck cancers report that their sense of taste is dulled, changed or lost during radiation treatment, causing them to lose interest in eating and diminishing their quality of life.

In a study of taste and smell dysfunction with 40 cancer survivors, scientists at the University of Illinois Urbana-Champaign found that the tips of these individuals’ tongues were significantly less sensitive to bitter, salty or sweet tastes than peers in the control group who had never been diagnosed with cancer.

In a paper published in the journal Chemical Senses, the U. of I. team said this diminished taste sensitivity suggested that the taste buds on the front two-thirds of the cancer survivors’ tongues or a branch of the chorda tympani facial nerve, which carries signals from the tip of the tongue to the brain, may have been damaged during radiation therapy.

“While most studies suggest that patients’ ability to taste recovers within a few months of treatment, patients report that they continue to experience taste dysfunction for years after treatment ends,” said M. Yanina Pepino, a professor of food science and human nutrition at the U. of I. “Our primary goal in this study was to test the hypothesis that radiation therapy is associated with long-term alterations in patients’ senses of smell and taste.”

Graduate student Raul Alfaro
Graduate student Raul Alfaro was the first author of the study, published in the journal Chemical Senses. © Photo by Audra E. Martin

While undergoing radiation and/or chemotherapy, head and neck cancer patients may lose taste buds, triggering a transient reduction in their ability to taste – a condition called hypogeusia – or their perception of tastes may be altered, a condition called dysgeusia that can also occur when nerves are damaged during cancer surgery, she said.

“Taste buds’ average lifespan of about 10 days enables rapid recovery from injury if the stem cells are preserved, yet it also makes the short-lived and long-lived cells within taste buds particularly vulnerable to the direct cytotoxic and anti-proliferative effects of chemotherapy and radiotherapy,” Pepino said.

Prior studies that explored taste loss and perception in these patients showed mixed results. Many of these studies involved “whole mouth” experiments that may not have detected regional damage to the taste buds at the front of the tongue or to the chorda tympani section of the facial nerve, said graduate student Raul Alfaro, the lead author of the study.

The U. of I. team assessed participants’ smell and taste functions separately and explored whether sensory interactions between taste and retronasal odors – aromas from food and beverages that are perceived in the oral cavity while eating or drinking – differed for the cancer survivors and the people in the control group.

 The team assessed participants’ ability to taste regionally by applying cotton swabs soaked in flavored solutions to the tips of their tongues.

They also evaluated participants’ whole-mouth taste function by having them swish solutions around in their mouths for five seconds and spit them out. For this test, the participants were presented with nine cups of liquids that contained both taste and smell sensory components. The cups contained two concentrations of strawberry extract in a sucrose solution, lemon extract in citric acid, salt in a vegetable broth and caffeinated instant coffee. They also received one cup of deionized water.

After sipping each sample, participants were asked to identify its taste quality – sweet, salty, bitter, umami (savory) or no sensation – and to rate the smell and taste intensity of the sample on a scale that ranged from “no sensation” to “strongest of any kind.”

Food science and human nutrition professor Anna E. Arthur and then-research fellow Sylvia L. Crowder seated at a table
Food science and human nutrition professor Anna E. Arthur and then-research fellow Sylvia L. Crowder were co-authors of the study. © Photo by L. Brian Stauffer

Participants tasted the samples twice – once wearing a nose clip and once without – to determine whether their taste perception differed when the nose clip blocked their retronasal olfactory cues.

When participants’ sense of taste was assessed using the whole-mouth test with or without the nose clip, they similarly rated the taste and smell of nearly all of the samples.

However, when participants’ sense of taste was assessed regionally at the tip of the tongue, the cancer survivors were more likely to respond they did not perceive a taste or to misidentify the taste quality – such as bitter, salty or sweet – of multiple samples.

“Although the results from the whole-mouth taste test suggested that head and neck cancer survivors’ taste function was normal and well preserved, results from the regional tests indicated that they had some deficits,” Pepino said. “Subtle taste dysfunction in the tip of the tongue persisted for several months after they completed their oncology treatments.

“Taste dysfunction at the tip of the tongue might sound unimportant; however, there is an elegant cross-talk between the nerves that conveys signals from the tip and the back of the tongue, such that taste signals in the tip of the tongue inhibit signaling from the back. This system allows taste intensity to remain constant in the whole mouth, even when taste signaling coming from the tip of the tongue is reduced. However, reduced signal input can also lead to phantom tastes, metallic taste and other oral symptoms.” 

Additional co-authors of the study were food science and human nutrition professor Anna E. Arthur, who is also the Sylvia D. Stroup Scholar in Nutrition and Cancer, and an oncology dietitian with the Carle Cancer Center; Dr. Kalika P. Sarma, a radiation oncologist at Carle Foundation Hospital and a clinical assistant professor in the Carle Illinois College of Medicine; and then-research fellow Sylvia L. Crowder.

The work was supported by grants from the U.S. Department of Agriculture National Institute of Food and Agriculture, the Academy of Nutrition and Dietetics, and the Division of Nutritional Sciences at the U. of I.

Crowder’s work on the project was supported by a Carle Illinois Cancer Scholars for Translational and Applied Research Fellowship, as well as a grant from the National Cancer Institute.

The paper “Taste and smell function in head and neck cancer survivors” is available from the News Bureau. DOI: 10.1093/chemse/bjab026

Featured image: Head and neck cancer survivors’ tongues are less sensitive at the tip, and problems with taste dysfunction may persist for years after patients complete oncology treatments, a team led by food science and human nutrition professor M. Yanina Pepino found in a study. © Photo by Luka Gruev


Provided by University of Illinois

The Evolution of Good Taste (Biology)

Does evolution explain why we can’t resist a salty chip? Researchers at NC State University found that differences between the elemental composition of foods and the elemental needs of animals can explain the development of pleasing tastes like salty, umami and sweet.

Taste tells us a lot about foods before they are swallowed and digested, and some tastes correspond with the elemental composition of foods. For example, an aged steak lights up the umami taste receptors, because it has a high concentration of the element nitrogen, which occurs in amino acid molecules. Nitrogen is essential for survival, but often occurs in low concentrations relative to the demand by animals. Likewise, sodium is limited in many foods in nature – think of life before supermarkets. So if you need sodium to survive – and all animals do – you are more likely to have adapted a taste for, and seek out, salty foods.

“Nutritional imbalances, even at the elemental level, can limit the growth and metabolism of animals,” says Lee Demi, a co-author of the study and postdoctoral researcher in NC State’s Department of Applied Ecology. “We posited that animals should have evolved the ability to taste, and enjoy, certain elements and nutrients that are most likely to be limiting for growth, due to their low concentrations in typical foods.” 

To investigate this hypothesis, Demi and colleagues compared the body elemental composition of three animal groups (mammals, fish, and insects) to the elemental composition of plants, the base of most food webs. They predicted that animals who eat foods composed of particular elements that are rare or unpredictable are more likely to have taste receptors that reward them for finding those same elements.

“Because animals have very limited ability to change their elemental composition, the old adage that ‘You are what you eat’ doesn’t really apply,” says Demi. “Rather, animals are rewarded with pleasing tastes for ‘eating what they are’, at least from an elemental composition perspective, which helps reduce the prospect of dietary nutrient limitation.”

This is particularly important for omnivorous and herbivorous animals that eat a variety of different foods which vary in nutritional quality. Within this framework, taste becomes a tool that helps consumers prioritize which foods they should search for and consume, so they don’t waste time on foods that have less of these necessary elements. Equally, taste can also inform consumers to avoid foods that contain too much of an element they need. This is why eating a handful of chips is more attractive than eating a handful of table salt. 

Where you are on the food chain can predict the complexity of your taste systems. Some top predators, like orcas, have lost many taste receptors over evolutionary time. This study suggests that predators are less likely to experience strong elemental imbalances in their diet than herbivores or omnivores. Because their prey already match their elemental needs, predators experience less selective pressure to maintain elaborate taste systems. However, these top predators have kept their taste for salt, which can be harmful if overconsumed.   

“Affinity for certain foods must have strong evolutionary drivers, because without taste, animals would be forced to overconsume everything in the hopes of hitting the magic ratio of elements needed for growth and development,” says Benjamin Reading, co-author of the study and a professor in NC State’s Department of Applied Ecology. “They would need to eat way too much and end up excreting huge quantities of those things they need less of, which is not efficient.”

The research team also found strong evidence of convergent taste evolution in mammals, fish, and insects. Each group, although far apart on the phylogenetic tree, all have adapted tastes that prioritize the same infrequent elements, including sodium, nitrogen and phosphorus.

“Phosphorus is particularly intriguing because this recently discovered taste is most strongly linked to phosphate, which is also the primary form of phosphorus in many nucleic acids, ATP, phospholipids, etc.,” says Brad Taylor, a co-author of the study and professor in NC State’s Department of Applied Ecology. “Phosphate is the most readily available form of phosphorus for uptake by plants, and often the primary growth limiting element in organisms and ecosystems. So, links between the elemental form, taste receptors, organismal needs, and ecosystem are really direct.”

While the neurobiological process of taste has been extensively researched, this study is the first to explore taste as an evolutionary tool for optimal foraging. The researchers suggest that this may open a new area of thought on how taste can indicate how animals impact their environments through foraging, nutrient-cycling, and other core principles of ecology.

The paper, “Understanding the evolution of nutritive taste in animals: Insights from biological stoichiometry and nutritional geometry,” is published in the journal Ecology and Evolution. The paper was co-authored by Michael Tordoff of the Monell Chemical Senses Center; and Rob Dunn from NC State’s Department of Applied Ecology and the Natural History Museum of Denmark.

The work was supported by the U.S. National Science Foundation [grant number 1556914] as well as the Department of Applied Ecology and Dr. Jules Silverman at North Carolina State University. 


Provided by NC State University

All in the Mind: Is Reality Real? (Philosophy)

Why the way we experience and interact with the world is entirely mind-made

Saltatory conduction is the process through which the brain receives information from the five sense organs, which include the eyes, ears, nose, tongue, and skin. When sense receptors in the sense organs are stimulated, electrochemical impulses travel via a process of neurotransmission from the peripheral nervous system to the central nervous system. Once received by the central nervous system, these electrochemical messages culminate in the brain where they are transformed into coherent information that can be acted upon.

Saltatory conduction was first identified in 1939 by Japanese born American biophysicist Ichiji Tasaki, and scientific understanding of the process has increased significantly since that time. However, although the mechanisms of this fundamental biological process are well documented, it appears that some important implications of saltatory conduction have been overlooked in the scientific literature – particularly in terms of how it can advance understanding of how we perceive reality.

More specifically, saltatory conduction provides evidence indicating that the reality we perceive and experience on a day-to-day basis is far less real or concrete than collective opinion might suggest. The reason for this is that without exception, our sense of movement, touch, taste, pain, pleasure, sight, sound, and so forth are the product of the brain filtering, transforming and organising electrochemical information into a working three-dimensional mental construction.

For example, when we look at a tree, what we see is the brain’s interpretation of electrochemical signals that were transmitted by sensory receptors in the eyes. Consequently, our perception of the tree isn’t “direct” but is the end product of a biophysical process involving receiving, transforming, transmitting and then retransforming information. The same applies if we reach out and touch the tree – we experience the brain’s reconstruction, based on input from electrochemical signals, of how it interprets the tree should feel to the hand.

A good way to understand this principle is to consider how information is processed using Voiceover Internet Protocol that underlies web-based video calling platforms such as Messenger, Skype and WhatsApp. In such instances, a caller’s camera and microphone capture analogue video and audio signals which are then compressed and transformed into digital numeric packets. These data packets are then transmitted over a digital network before being decompressed and transformed back to analogue video images and audio sounds by the recipient’s video conferencing system. However, at no point can it be said that the two callers’ interaction with each other is unmodified and direct, as their video call is subject to various stages of data transformation and transportation.

A similar type of “data transformation” process occurs during saltatory conduction such that in reality, we never directly touch, smell, see, hear, or taste sensory phenomena. Consequently, although we have the impression of living in and moving through a physical world, we never truly go anywhere or do anything because at any given time, our experience of life corresponds to the mental projection of the brain. In other words, the manner by which we experience and interact with the world is entirely mind-made – we project a reality and then relate to it entirely within the realm of the mind.

Consider the analogy of a dream whereby the dreamer is invariably under the impression that what they are experiencing is real. For example, when dreaming, individuals can have the sensation of coming or going, pleasure or pain, and fast or slow. In fact, an individual can experience a dream as being real to the extent that it causes them to wake up screaming if the dream is sufficiently frightening. However, although the dream may appear real, in truth it has no material existence and unfolds completely within the expanse of the mind. In a dream, nothing really comes or goes, there is no here or there, no near or far, no up or down, and no fast or slow.

However, it’s not correct to assert that what we experience during dreamt or waking reality is unreal, because regardless of whether a phenomenon or situation exists in material absolute terms or is just a fabrication of the mind, we still undergo an authentic experience. Indeed, the extent to which a given experience is designated as authentic or meaningful is highly subjective and varies according to context and how the mind has been conditioned.

Nevertheless, it appears that as part of some fundamental biological processes such as saltatory conduction, there exists evidence suggesting a need to re-examine the accuracy of certain widely accepted scientific assumptions concerning the underlying nature of mind and matter. Perhaps through fostering a better understanding of the inseparability between mind and matter in this manner, new psychological and technological approaches will emerge that better enable humans to harness resources and benefit from both their psychological and physical world.

References: (1) Shonin, E., & Van Gordon, W. (2014). Dream or reality? Philosophy Now, 104, 54 (2) Soeng, M. (1995). Heart Sutra: Ancient Buddhist Wisdom in the Light of Quantum Reality. Cumberland: Primary Point Press. (3) Van Gordon, W., Sapthiang, S., Barrows, P., & Shonin, E. (2020). Understanding and practicing emptiness. Mindfulness, Advance Online Publication, DOI: 10.1007/s12671-020-01586-1 (4) Van Gordon, W., Shonin, E., Dunn, T., Sapthiang, S., Kotera, Y., Garcia-Campayo, J., & Sheffield, D. (2019). Exploring emptiness and its effects on non-attachment, mystical experiences, and psycho-spiritual wellbeing: A quantitative and qualitative study of advanced meditators. Explore: The Journal of Science and Healing, 15, 261-272. (5) Vogel, H. (2009). Nervous System: Cambridge Illustrated Surgical Pathology. New York: Cambridge University Press. (6) Wireless Research Centre (n.d.). How Voice and Video Call Works? Available from: https://danenet.wicip.org/2019/04/23/how-voice-and-video-call-works/

Copyright of this article totally belongs to Dr. William Van Gordon, who is a Chartered Psychologist and Associate Professor of Contemplative Psychology at the University of Derby (UK). This article is republished here from psychology today under common creative licenses

Danish and Chinese Tongues Taste Broccoli and Chocolate Differently (Food)

Two studies from the University of Copenhagen show that Danes aren’t quite as good as Chinese at discerning bitter tastes. The research suggests that this is related to anatomical differences upon the tongues of Danish and Chinese people.

The tongue-coordinate system which the researchers developed for mapping papillae. © University of Copenhagen

For several years, researchers have known that women are generally better than men at tasting bitter flavours. Now, research from the University of Copenhagen suggests that ethnicity may also play a role in how sensitive a person is to the bitter taste found in for example broccoli, Brussels sprouts and dark chocolate. By letting test subjects taste the bitter substance PROP, two studies demonstrate that Danish and Chinese people experience this basic taste differently. The reason seems to be related to an anatomical difference upon the tongue surfaces of these two groups.

“Our studies show that the vast majority of Chinese test subjects are more sensitive to bitter tastes than the Danish subjects. We also see a link between the prominence of bitter taste and the number of small bumps, known as papillae, on a person’s tongue,” says Professor Wender Bredie of the University of Copenhagen’s Department of Food Science (UCPH FOOD).

A taste of artificial intelligence

Using a new artificial intelligence method, researchers from UCPH FOOD, in collaboration with Chenhao Wang and Jon Sporring of UCPH’s Department of Computer Science, analysed the number of mushroom-shaped “fungiform” papillae on the tongues of 152 test subjects, of whom half were Danish and half Chinese.

Fungiform papillae, located at the tip of the tongue, are known to contain a large portion of our taste buds and play a central role in our food and taste experiences. To appreciate the significance of papillae in food preferences across cultures and ethnicities, it is important to learn more about their distribution, size and quantity.

The analysis demonstrated that the Chinese test subjects generally had more of these papillae than the Danish subjects, a result that the researchers believe explains why Chinese people are better at tasting bitter flavours.

However, Professor Bredie emphasizes that larger cohorts need to be examined before any definitive conclusions can be drawn about whether these apparent phenotypical differences between Danes and Chinese hold at the general population level.

More knowledge about differences in taste impressions can be important for food development. According to Professor Bredie:

“It is relevant for Danish food producers exporting to Asia to know that Asian and Danish consumers probably experience tastes from the same product differently. This must be taken into account when developing products.”

Danes prefer foods that require a good chew

Professor Wender Bredie points out that genetics are only one of several factors that influence how we experience food. Another significant factor has to do with our preferences — including texture. Think, for example, of the difference between munching on crispy potato chips from a newly opened bag, compared to eating softened ones from a bag opened the day before. Here, many Danes would probably prefer the crispy ones over the soft ones, even if the taste is similar. According to the UCPH studies, there seems to be a difference between the Danish and Chinese test subjects on this point as well.

While the vast majority of Chinese subjects (77%) prefer foods that don’t require much chewing, the opposite holds true for the Danish subjects. Among the Danes, 73% prefer eating foods with a harder consistency that require biting and chewing – rye bread and carrots, for example.

The reason for this difference remains unknown, but the researchers suspect that it stems from differences in food culture and the ways in which we learn to eat. The studies do not point to tongue shape as making any difference.

THE NEW METHOD:

Because the counting of tongue papillae is usually done manually, and a tongue has hundreds of tiny fungiform papillae, it is a demanding job in which mistakes are easily made.

The new method, based on artificial intelligence and developed by image analysis experts Chenhao Wang and Jon Sporring of the Department of Computer Science, automates the counting and delivers precision. Using an algorithm, they have designed a tongue-coordinate system (see figure) that can map papillae on individual tongues using image recognition.

ABOUT THE RESEARCH:

  • The 152 study participants were all healthy non-smokers between the ages of 18 and 55. Of them, 75 were from Denmark and 77 from China. 71% of participants were women and 29% men.
  • Test subject sensitivity to bitter taste was examined by allowing subjects to taste the bitter substance 6-n-propylthiouracil (PROP), considered a genetic marker for differences in taste perception.
  • The research was conducted by: Jing Liu and Wender Bredie from the Department of Food Science; Chenhao Wang and Jon Sporring from the Department of Computer Science; Camilla Cataneo and Ella Pagliarini from the University of Milan; and Anne C. Bech from Arla Innovation Centre. The research received support from Arla Foods amba and the Capital Region of Denmark.
  • Research articles for the two studies can be found here:https://link.springer.com/chapter/10.1007/978-3-030-59722-1_4
    https://www.sciencedirect.com/science/article/pii/S0950329319304653

Provided by Faculty of Science- University of Copenhagen

Sweet Taste Reduces Appetite? (Food)

The sweet taste of sugar is very popular worldwide. In Austria and Germany, the yearly intake per person adds up to about 33 and 34 kilograms, respectively. Thus, sugar plays an increasingly role in the nutrition and health of the population, especially with regard to body weight. However, little is known about the molecular (taste) mechanisms of sugar that influence dietary intake, independently of its caloric load.

Taste receptor and satiety regulation

“We therefore investigated the role of sweet taste receptor activation in the regulation of satiety,” says Veronika Somoza, deputy head of the Department of Physiological Chemistry at the University of Vienna and director of the Leibniz Institute for Food Systems Biology at the Technical University of Munich.

For this purpose, the scientists conducted a blinded, cross-over intervention study with glucose and sucrose. A total of 27 healthy, male persons, between 18 and 45 years of age, received either a 10 percent glucose or sucrose solution (weight percent) or one of the sugar solutions supplemented with 60 ppm lactisole. Lactisole is a substance that binds to a subunit of the sweet receptor and reduces the perception of sweet taste. Despite different types of sugar, all solutions with or without lactisole had the same energy content.

Two hours after drinking each of the test solutions, the participants were allowed to have as much as breakfast they wanted. Shortly before and during the 120-min waiting period, the researchers took blood samples in regular intervals and measured their body temperature.

Additional 100 kilocalories on average

After the consumption of the lactisole-containing sucrose solution, the test persons had an increased energy intake from breakfast of about 13 percent, about 100 kilocalories more, than after drinking the sucrose solution without lactisole. In addition, the subjects of this group showed lower body temperature and reduced plasma serotonin concentrations. Serotonin is a neurotransmitter and tissue hormone which, among other things, has an appetite-suppressing effect. In contrast, the researchers observed no differences after administration of the lactisole-containing glucose solution and the pure glucose solution.

“This result suggests that sucrose, regardless of its energy content, modulates the regulation of satiety and energy intake via the sweet taste receptor,” says Barbara Lieder, head of Christian Doppler Laboratory for Taste Research and also deputy head of the Department of Physiological Chemistry of the Faculty of Chemistry at University of Vienna.

The first study author of the study, Kerstin Schweiger, University of Vienna adds: “We do not know yet why we could not observe the lactisole effect with glucose. However, we suspect it is because glucose and sucrose activate the sweet receptor in different ways. We also assume that mechanisms independent of the sweet receptor play a role.”

“So there is still a lot of research needed to clarify the complex relationships between sugar consumption, taste receptors and satiety regulation on the molecular level,” says Veronika Somoza. In particular, as sweet receptors are also found in the digestive tract and little is known about their function there. The first steps have nevertheless been taken.

References : Sweet Taste Antagonist Lactisole Administered in Combination with Sucrose, But Not Glucose, Increases Energy Intake and Decreases Peripheral Serotonin in Male Subjects: Schweiger K et al., Nutrients 2020, 12(10), 3133; https://www.mdpi.com/2072-6643/12/10/3133

Provided by University of Vienna

High Noise Levels Can Decrease The Food Liking (Food)

Previous studies have shown that background noise can affect the liking of food. However, little is known about the liking of food in the presence of different background noise types and levels. Now, Mahmoud A. Alamir and colleagues in their paper investigated food liking, relative to the background noise in the room (i.e. no noise conditions), for three background noise types (relaxing music, road traffic noise and restaurant noise) and three noise levels (30, 40 and 50 dBA).

©gettyimages

Fifteen participants rated liking of food using an 11-point Likert scale. Dose-response relationships of food liking in the presence of different background noise types and levels were presented.

The results indicated that the type of background noise affected the liking of food (F(2, 97) = 134, p < 0.001). The increase in the level of the noise also decreased the liking of food regardless of the noise type (F(2, 77) = 41, p < 0.001). Relaxing music increased the liking of food at 30 and 40 dBA relative to the background noise in the room (i.e. no noise condition) by (mean ± SE) 60 ± 10 and 38 ± 10%, respectively. Restaurant noise and road traffic noise decreased the liking of food at all levels, compared to the background noise in the room (p < 0.001).

Their findings can help identify and quantify types and levels of background noise that can increase the enjoyment of food. These results could also be helpful in choosing and designing dining areas with background noise that increase food enjoyment.

References: Mahmoud A. Alamir, Kristy Hansen, “The effect of type and level of background noise on food liking: A laboratory non-focused listening test”, Applied Acoustics, Volume 172, 15 January 2021, 107600 doi: https://doi.org/10.1016/j.apacoust.2020.107600 link: https://www.sciencedirect.com/science/article/abs/pii/S0003682X20307040?via%3Dihub

Learning To Like Bitter Flavors Isn’t Just In Your Head – It’s In Your Saliva (Biology)

Kids generally hate coffee, but somewhere along the line, most of us learn to love it. Same goes for dark chocolate. And IPAs have been the reigning monarchs of the craft beer world since the early 2000s, despite the fact that it’s much cheaper to simply chew on a pinecone wrapped in a dirty sock. Still, some people clearly appreciate the flavor. And thanks to the SPIT Lab, we know exactly why. Spoiler alert: There’s a pretty big clue in the name of the research facility.

As much as this author might hate them, a lot of people seem to like the bitterest beers. Likewise, dark chocolate, red wine, and black coffee are all wildly popular foods with a distinctly bitter flavor. According to a new report from Purdue’s SPIT lab, even those of us who prefer crisp pilsners and rich stouts might benefit from trying more IPAs. In time, the bitter flavors can actually change the way we experience taste.

You’ve probably had the experience of tasting something that slowly grows on you. Actually, there’s some pretty good evidence that everyone develops an ability to enjoy bitter food more as they get older, with children being especially sensitive to it. There’s a reason why kids notoriously despise eating their greens. But Dr. Cordelia Running, the director of the lab, wanted to explore the actual mechanism for that transformation.

See, saliva isn’t just what keeps your tongue moist; it’s the biochemical medium of the mouth. That means that every chemical reaction that happens between your tongue and teeth is carried out against a backdrop of saliva. Dr. Running and her team decided to take a closer look at the mouth’s most faithful companion.

Bitter foods like dark chocolate get their biting taste from chemicals known as polyphenols, and Running’s team suspected that learning to like these flavors comes from being better able to process these chemicals. To test their theories, Running’s team recruited 64 participants to start on an alternating weekly diet set to last six weeks: one week they’d give up bitter food altogether, the next they’d be asked to consume three glasses of polyphenol-rich chocolate almond milk per day. Just as the team hypothesized, participants who were in the chocolate-consuming part of the cycle began naturally producing a new kind of protein in their saliva — one that easily binds and captures those polyphenols. At the same time that this protein began to show its face, the participants reported that they enjoyed the drink more and experienced it as less bitter or astringent.

We know, we know. By this point, you’re asking yourself how we could have possibly gotten this far in the article without addressing the fact that all of this info comes from the SPIT Lab. Yes, it’s a great name. Yes, it’s very descriptive. And no, this examination into the experience of bitterness isn’t the only significant work to have come out of it. The lab does a lot of work on saliva, but that’s not all. SPIT Lab is short for Saliva, Perception, Ingestion, and Tongue Lab, and their focus is on all of the ways the mechanics of the mouth can alter the experience of eating and tasting.

Another experiment known as the desensitization test is one of the more interesting projects to have come out of the lab. The team wanted to dive into the experience of eating spicy and bitter food, so they fed a group of participants a combination of bitter seltzer water and chili-oil-spiked ginger beer — either they would drink one then the other, or two of the same. They found that sensitization absolutely did not occur, meaning that taking in more spiciness did not make the next spicy drink taste even hotter, and a similar effect was seen with the bitter drink. One spicy beverage did, however, make the next one taste milder. Perhaps most surprisingly, a drink of the spicy ginger beer made the bitter seltzer water taste that much more bitter, likely because of the contrast between the two flavors. So if you really want to revel in the fingernail-curling hops of your local brewery’s next release, load up on hot sauce first.

Sorry — Pop Music Sounds The Same Because You Want It That Way (Psychology)

Does it ever seem like pop music on the radio is all just the same song repackaged? That’s not your imagination; the large majority of radio hits are written and produced by a handful of the same people. When the variety of choices we have as consumers seems to be at an all-time high, why is pop music so monotonous? We hate to break it to you, but it’s because your brain loves the familiar — whether you like it or not.

In 1968, social psychologist Robert Zajonc asked 100 college students to look at a list of antonym pairs (things like “high/low,” “able/unable,” and “optimism/pessimism”) and asked them to choose the one in each pair that they thought had “the more favorable meaning.” He then compared their results to each word’s frequency in the English language. Overwhelmingly, the participants thought the more common word was the more favorable one. The phenomenon that makes you think more familiar things are more pleasant is known as the mere exposure effect, and it’s a big reason music producers keep pumping out the same sounds you’ve heard before.

Even at the turn of the 20th century, people knew that music sounded better the more you listened to it. In 1903, Max Meyer published a report in Experimental Studies in the Psychology of Music showing that when people heard a song that was foreign to them (in this case, quarter-tone music, like the kind common to Chinese cultures), they reported liking it more after every repetition.

Areas in the brain associated with emotion- related and reward circuitry are significantly more active for familiar music than unfamiliar music. Whether you like a song or not appears to play less of a role in generating an emotional response. Image: Pereira CS, TeixeiraJ, Figueiredo P, XavierJ, Castro SL, Brattico E (2011) Music and Emotions in the Brain: Familiarity Matters. PLOS ONE

Of course, modern technology drives this point home even more. A 2011 fMRI study found that the emotion and reward centers of the brain were more active when subjects heard familiar music than when they heard unfamiliar music, and a 2013 study found that subjects’ emotional arousal was higher after hearing a familiar song, even if the subjects didn’t remember hearing it before. You might think you’re an adventurous music fan, but your brain just loves the songs it knows.

Music producers know this all too well. According to The New Yorker, “A relatively small number of producers and top-liners [people who write the melodies and lyrics] create a disproportionately large share of contemporary hits, which may explain why so many of them sound similar.” Just take songwriter Max Martin, for example. The Swedish 40-something is responsible for a jaw-dropping number of hits, ranging from those performed by the Backstreet Boys, ‘NSync, and Britney Spears to more modern artists like Katy Perry and Taylor Swift.

The key is to mix the comfort of the familiar with a little bit of surprise. “Within the vein of all the other successful pop music, [it helps when] someone does something that’s just a little bit different,” music professor Clay Stevenson tells Pigeons & Planes. “So maybe they throw in a different instrument, maybe they throw in an extended bridge, or an extended part to their hook.”

But there’s a silver lining to all this. The fact that familiarity breeds favoritism means that with a little bit of extra work, you can easily expand your musical tastes. When you listen to something new, put it on repeat a few times. If you don’t like it after a handful of listens, well, it wasn’t meant to be. But if science has proven anything, you very well might find a new favorite.


Scientists Discovered New Type of Taste Receptor Cells (Biology)

Scientists have discovered a new population of taste cells that can detect multiple types of stimuli, including chemicals from different taste qualities.

Fig: Most taste cells selectively respond to a specific stimulus type while broadly responsive cells respond to multiple taste qualities. Image credit: Jhanna Flora / Kathryn Medler.

They employ three types of taste cells: Type I cells acts as support cells; Type II cells detect bitter, sweet and umami tastes; and Type III cells detect sour and salty flavors.

To better understand how taste cells detect and signal the presence of different tastes, Dr. Kathryn Medler from the University at Buffalo and colleagues used an engineered mouse model to investigate the signaling pathways that the animals use to relay taste information to the brain.

The researchers discovered a previously unknown subset of Type III cells that were ‘broadly responsive’ and could announce sour stimuli using one signaling pathway, and sweet, bitter and umami stimuli using another.

The idea that mammals might possess broadly responsive taste cells has been put forth by multiple lab groups, but previously, no one had isolated and identified these cells.

The scientists suspect that broadly responsive cells make a significant contribution to our ability to taste.

Their discovery provides new insight into how taste information is sent to the brain for processing, and suggests that taste buds are far more complex than we currently appreciate.


References: D. Dutta Banik et al. 2020. A subset of broadly responsive Type III taste cells contribute to the detection of bitter, sweet and umami stimuli. PLoS Genet 16 (8): e1008925; doi: 10.1371/journal.pgen.1008925 ; link: https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1008925