Tag Archives: taste

Tongue.

The human tongue can actually ‘smell’ things

New research shows that the senses or taste and smell are much more intertwined than we’ve previously thought.

Tongue.

Image via Pixabay.

A team of researchers from the Monell Center report finding functional olfactory receptors — the sensors that detect odors in the nose — in the taste cells of our tongues. The findings suggest that the interactions between smell and taste, both of which comprise flavor, may actually begin on the tongue and not in the brain.

Smelling strawberries

“Our research may help explain how odor molecules modulate taste perception,” said study senior author Mehmet Hakan Ozdener, MD, PhD, MPH, a cell biologist at Monell.

“This may lead to the development of odor-based taste modifiers that can help combat the excess salt, sugar, and fat intake associated with diet-related diseases such as obesity and diabetes.”

You know how we recognize that something smells like strawberries, even though strawberries themselves don’t have a smell when you sniff them? This shows you how smell helps create flavor.

The sense of taste handles sweet, salty, sour, bitter, and umami (savory) molecules on the tongue. It evolved as a quick way for our brains to figure out how nutritious something we’re chewing on is, and make sure it’s not toxic or poisonous. But smell, too, was an important part in detecting the next snack. A pear and an apple taste pretty much the same if you hold your nose while eating. What our brains do when we eat something is to combine taste and smell, alongside information from other senses, to create what we perceive as flavor.

Common wisdom held that information from taste and smell stays separate until reaching the brain. However, Ozdener realized no one has previously checked this assumption. He thought of this when when his 12-year-old son asked him if snakes extend their tongues so that they can smell. So, alongside colleagues at Monell, Ozdener set about culturing living human taste cells.

After developing the techniques that would allow them to maintain such a culture, the team probed the cells, finding many of the molecules present in human olfactory receptors. Next, they employed calcium imaging to show that these cells respond to odor molecules in a manner similar to olfactory receptor cells. Taken together, the data points to olfactory receptors playing a role in our taste systems — possibly by interacting with taste receptors on the tongue. Other experiments by the Monell scientists demonstrated that a single taste cell can contain both taste and olfactory receptors, which supports the present findings.

“The presence of olfactory receptors and taste receptors in the same cell will provide us with exciting opportunities to study interactions between odor and taste stimuli on the tongue,” said Ozdener.

The findings help us better understand how smell and taste interact. However, they could also better inform us about either of those senses individually. We still don’t know, for example, what compounds activate the vast majority of the 400 types of functional human olfactory receptors. The cells cultured by the team, which respond to odors, could be used to screen molecules that bind to such receptors.

The paper “Mammalian Taste Cells Express Functional Olfactory Receptors” has been published in the journal Chemical Senses.

A matter of taste: tongue differences shape our palate

New research at the University of Copenhagen found that Danes can’t perceive bitter taste as well as Chinese individuals. This seems to come down to anatomic differences on the surface of the tongue between these two groups. The findings showcase how ethnicity can influence our enjoyment of food, but may also showcase how our natural differences in perception can help give rise to cultural preferences.

Image via Pixabay.

We’ve known for a while now that not everybody perceives tastes the same. Women, for example, are better at picking up bitter flavors than men. New research suggests that ethnicity can also play a role in our sensitivity to bitter taste, and thus, our enjoyment of items such as broccoli or dark chocolate.

A matter of taste

“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) and coauthor of the study.

The team used artificial intelligence to analyze the density of mushroom-shaped “fungiform” papillae on the tongues of 152 test subjects, half of them ethnically Danish, and half ethnically Chinese. These papillae are concentrated to the tip of the tongue and they contain a large part of our taste buds — as such, they’re a key player in our ability to perceive taste. In order to understand whether cultural preferences for particular tastes are mediated by these papillae, the team first set out to see what differences in the distribution, size, and quantity of papillae exist between different groups of people.

Papillae are usually counted by hand, making it a very slow and tedious, labor-intensive process. It also means that mistakes are often made (there are hundreds of tiny fungiform papillae on every tongue). This new method allowed for automated counting, which is much faster and reliable. The method uses a tongue-coordinate system to map individual papillae using image recognition, and is described in the first of these two papers.

All in all, participants of Chinese descent had (generally) more of them than Danish subjects, which the team believes explains why the former are better able to pick up on bitter flavors. Still, Professor Bredie underscores that the findings need to be replicated on larger groups of participants before we can draw a definitive conclusion here; the study may have picked up on a fluke, and these differences may not hold at the general population level.

“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,” Bredie says. “This must be taken into account when developing products.”

Genetic factors are only one of the elements that influence our experience of food. Our personal preference also has a big part to play. Professor Bredie uses texture as an example, explaining that many Danes would likely prefer crispy chips over soft chips. Previous research at the UCPH showed that Danish and Chinese test subjects likely differ on this point as well — it found that a majority of Chinese subjects (77%) prefer foods that don’t need much chewing, whereas a majority of Danes (73%) like those with a harder consistency.

Exactly what causes this divergence in preference is unknown, but the team believes it’s due to cultural and diet differences and not down to the structure of our tongues.

The first paper, “A Novel Approach to Tongue Standardization and Feature Extraction” has been presented at the International Conference on Medical Image Computing and Computer-Assisted Intervention.

The second paper, “Cross-cultural differences in lingual tactile acuity, taste sensitivity phenotypical markers, and preferred oral processing behaviors” has been published in the journal Food Quality and Preference.

Our genes could make us seek, or avoid, fatty foods

While most of us would agree that fat (when properly used) makes food taste amazing, new research shows this isn’t a steadfast law. Our enjoyment of fats lies, at least in part, on having the right genes for it.

Image credits Steve Buissinne.

New research from the Monell Chemical Senses Center in Philadelphia, Pennsylvania found that our genetic makeup plays an important role in our enjoyment (and even perception) of fatty foods.

Fat chance

“Person-to-person diversity in the positive perception of fattiness derives partially from an individual’s genetic make-up,” said senior author Danielle Reed, PhD, Monell Associate Director.

“How the taste, smell, and flavor of food and drink affect liking, and therefore the amount and type of food consumed, ultimately affects human health.”

The team worked with identical and fraternal twins who had reached adulthood and attended the annual Twins Days Festival in Twinsburg, OH, in 2018.

Participants were asked to rate how good low- and high-fat potato chips tasted, and estimate how much fat they contained. Participants also gave a saliva sample so the team could look at their DNA.

Genetically-identical twins had more similar preferences for the chips compared to fraternal twins (which are more genetically-distinct). The team also sequenced the genetic material of these participants, looking at hundreds of thousands of locations in their DNA strands where relevant genes were likely to lie.

The use of twins allowed the team to compare very similar genomes, and they identified two new specific gene variants that correlated with the enjoyment of fatty food.

The findings are important because our enjoyment of food drives our purchasing patterns, the authors explain.

“Most people assume more liking drives more intake, but decades of research tell us the reverse is true — we avoid what we don’t like,” said Hayes. “I may love bacon, but if I listen to my cardiologist, I’m still not going to eat it every morning.”

The results suggest that although fats are an important part of our food, some people are born with a genetic makeup that pushes them to like, or avoid, fat. In the future, the team plans to examine whether such factors are universal by testing people around the world with different types of fat in different food items.

The paper “Studies of Human Twins Reveal Genetic Variation That Affects Dietary Fat Perception” has been published in the journal Chemical Senses.

Some COVID-19 patients don’t recover their sense of smell or taste after all other symptoms go away

Almost 90% of those who lost their taste and smell after falling ill with COVID-19 fully regained them or improved within a month. But about 10% of such cases never regained the two senses during the study’s observation period, highlighting long-term problems that the virus could bring.

Credit Flickr

An international team of researchers studied a group of 202 Italians that were infected but weren’t ill enough to be hospitalized. They were asked to rate their sense of smell or taste after being diagnosed and then again a month later through phone interviews. A six-point scale was used, scoring 0 for no problem and 5 for complete loss of the sense.

The loss of the sense of smell or taste was recognized as one of the core symptoms of people infected with the coronavirus. It was first observed in hospitalized patients but then also in those with mild disease. While understanding is limited, initial studies suggested that this could be caused by the disruption of cells that support olfactory neurons.

The study found that 113 of the patients – about two-thirds – reported loss of taste and/or smell up to two weeks before they tested positive. Of that total, 55 said they had recovered fully, 46 reported improvements in their symptoms and 12 said their symptoms were unchanged or worse.

“Although altered sense of smell or taste showed an improvement in most cases during the course of the disease, these symptoms were still the most frequently reported by patients with COVID-19 4 weeks after testing,” the researchers wrote. “However, the persistence of altered sense of smell or taste was not associated with the persistence of the SARS-CoV-2 infection at control swab”

The median length of time the patients went without being able to smell or taste at all was a little more than 11 days, according to the findings. There was no correlation between those patients who again tested positive for COVID-19 four weeks after their initial diagnosis and those who were still having trouble smelling or tasting at this point.

The researchers believe this means an active loss of one or both of those senses cannot be considered proof of an active COVID-19 infection, theorizing that it takes the body some time to “repair and regenerate” the senses regardless of whether the virus has left the body.

Age and sex were not found to be significant factors affecting the rate of recovery from anosmia or dysgeusia. However, those patients who reported the most significant losses of smell and/or taste also tended to report the worst recoveries after four weeks – again suggesting that it takes the body time to reverse the damage done to the senses by COVID-19.

“Even with a high rate of resolution, the staggering number affected by this evolving pandemic suggests an almost certain deluge of patients likely to present for the treatment of unresolved symptoms,” Dr. Joshua Levy of the Emory University School of Medicine in Atlanta and co-author. said in a statement

Levy suggested that in long-term cases, people could consider therapy such as smell-training to help restore the senses. UK Professor Claire Hopkins, one of the researchers behind the study, said the team is now conducting more research on people with long-lasting symptoms.

“For people who recover more quickly it is likely the virus has only affected the cells lining their nose,” she told the BBC. “For people who recover more slowly it may be that the virus has affected the nerves involved in smell, too. It can take longer for these nerve cells to repair and regenerate.”

The study was published in the journal JAMA.

Credit: Pixabay.

Eating while standing makes food taste worse

Credit: Pixabay.

Credit: Pixabay.

Food trucks are trendy, supplying fast food to hungry hipsters at festivals and busy corporate executives in business districts alike. Street food managers, however, might want to take into consideration the findings of a new study, if they care about their customers’ satisfaction and their business’ bottom line. According to researchers at the University of South Florida, eating while standing reduces one’s enjoyment and intake of food compared to eating while seated.

Standing food tastes worse

Researchers recruited 358 participants who took part in six experiments inside a lab. They either had chairs to sit in or none at all. Although the participants were told that they were there to take part in a simple taste test, 15 participants figured out the real purpose of the study and had to be excluded from it.

In order to understand how physical discomfort influences our perception of food and beverage, the researchers asked the volunteers to sample food under various conditions either sitting or standing. In each situation, the volunteers had to rate their physical and psychological stress, as well as how much they enjoyed the food. Across the board, sitting produced significantly more enjoyment of food than standing.

Next, the research team conducted three experiments meant to tease apart the interaction between discomfort and sensory perception.

During one notable experiment, the participants ate a cookie while standing after drinking a placebo drink which was supposedly meant to induce “physical relaxation”. Those who drank the fake-relaxing beverage rated the cookie as tastier than other standing participants who did not receive the drink, although not nearly as enjoyable as sitters. Another similar experiment evaluated how relaxation influenced the enjoyment of food with unpleasant-tasting foods. When participants sampled an overly salty brownie while standing they were more likely to rate it as less pleasant than those who were sitting.

These experiments suggest that sitting or standing can change a person’s attitude towards food or drink by shifting attention to the sensory experience. When you notice the feeling of discomfort from standing, it’s easier to be less impressed by good or bad food because you’re less focused on taste.

In a final experiment, the participants rated hot coffee while sitting or standing. The researchers were looking to establish how the two situations affected the perception of temperature. Those who were standing consumed less coffee and were less able to notice temperature than sitters.

The authors of the new study published in the Journal of Consumer Research say that their findings highlight an often ignored “sixth sense”: the vestibular sense which is responsible for balance and spatial orientation. Restaurant managers should be particularly concerned with the findings of their new study. Adding just a couple of sitting options to their food truck or street restaurant could significantly improve their clients’ satisfaction. On the flipside, if a person is looking to eat less food for weight management purposes, eating while standing might prove to be a nifty tactic.

“These findings have conceptual implications for broadening the frontiers of sensory marketing and for the effects of sensory systems on food taste perceptions. Given the increasing trend toward eating while standing, the findings also have practical implications for restaurant, retail, and other food-service environment designs,” the authors concluded.

Tomato.

Team sequences the pan-genome of tomatoes in a bid to make them tasty again

Researchers at the Agricultural Research Service (ARS) and the Boyce Thompson Institute (BTI) want to bring back the tasty tomato of yore.

Tomato.

Image credits Mauro Borghesi.

Sadly, it seems that store-bought tomatoes just aren’t very tasty. An international research team thinks they have the way to fix this tasteless problem, though. They have finished constructing the pan-genome for the cultivated tomato and its wild relatives, mapping almost 5,000 previously undocumented genes. Armed with this knowledge, researchers might be able to bring the flavor back.

They don’t make them like they used to

“These novel genes discovered from the tomato pan-genome added substantial information to the tomato genome repertoire and provide additional opportunities for tomato improvement,” says co-author Zhangjun Fei, a bioinformatics scientist at the Boyce Thompson Institute.

“The presence and absence profiles of these genes in different tomato populations have shed important lights on how human selection of desired traits have reshaped the tomato genomes.”

A genome is the map of an organism’s genes and their functions. Genomes are, unsurprisingly, sequenced for individual organisms, and these are in turn used to create a kind of reference genome for the rest of the species. The team’s pan-genome, on the other hand, includes all of the genes from 725 different cultivated and closely related wild tomatoes, which revealed 4,873 genes that were absent from the original reference genome.

So what seems to be the problem with our tomatoes? Where’s the taste? The team reports that cultivated tomatoes show a wide range of physical and metabolic variation but, by and large, they’ve all been through several severe bottlenecks during their domestication and later breeding. In effect, this means that today’s tomatoes aren’t very genetically diverse.

Modern breeders, the team explains, have focused on traits such as yield, shelf life, disease resistance, and stress tolerance, which are economically important to growers. However, the pan-genome does point to a few genes we can use to improve the flavor, too.

“One of the most important discoveries from constructing this pan-genome is a rare form of a gene labeled TomLoxC, which mostly differs in the version of its DNA gene promoter,” explained James Giovannoni, a molecular biologist at the Agricultural Research Service (ARS) and paper co-author.

“The gene influences fruit flavor by catalyzing the biosynthesis of a number of lipid (fat)-involved volatiles–compounds that evaporate easily and contribute to aroma.”

TomLoxC also facilitates the production of apocarotenoids — a class of organic chemicals derived from carotenoids including vitamin A precursors — which function as signaling molecules for various responses in plants, including environmental stresses. The compounds also have a variety of floral and fruity odors that are important in tomato taste, the team notes.

The rarer version of TomLoxC was found in only 2% of older or heirloom varieties of large tomato. The common version was present in 91% of currant-sized wild tomatoes, primarily Solanum pimpinellifolium, the wild predecessor of the cultivated tomato. It is becoming more common in newer varieties.

“It appears that there may have been strong selection pressure against or at least no selection for the presence of this version of TomLoxC early in the domestication of tomatoes,” Giovannoni added. “The increase in prevalence of this form in modern tomatoes likely reflects breeders’ renewed interest in improved flavor.”

The team says that with the pan-genome in hand, breeders should be able to quickly increase the flavor of mass-produced tomatoes without sacrificing the traits that make them so economically-viable.

“These novel genes discovered from the tomato pan-genome added substantial information to the tomato genome repertoire and provide additional opportunities for tomato improvement. The presence and absence profiles of these genes in different tomato populations have shed important lights on how human selection of desired traits have reshaped the tomato genomes,” said Fei.

The team also expects that the nearly new tomato 5,000 genes they’ve identified in the pan-genome will help breeders improve it in further ways. Tomatoes, although they are fruits, botanically, are one of the most eaten vegetables worldwide, with a total annual production of 182 million tons (worth more than $60 billion). In the U.S., tomatoes are the second-most consumed vegetable after potatoes. Each American eats an average of 20.3 pounds of fresh tomatoes and an additional 73.3 pounds of processed tomatoes per year (estimated based on 2017 figures).

The paper “The tomato pan-genome uncovers new genes and a rare allele regulating fruit flavor” has been published in the journal Nature Genetics.

Cheese.

Novel approach to identifying flavor molecules poised to make fermented goods even more delicious

The Germans are coming for your cheese! They want to make it tastier!

Cheese.

Image credits Corinna Barbara.

Researchers from the Technical University of Munich (TUM), the Leibniz-Institute for Food Systems Biology, and the University of Hohenheim have developed a new technique for identifying flavor-bearing protein fragments in fermented foods such as cheese or yogurt. They hope that their findings will form a launchpad from which to upgrade the tastiness of a wide range of foodstuffs.

Cheesy business

Just like everything else, fermented foods draw a lot of their taste from volatile aromatic compounds. Unlike most other things, however, the flavor profile of items like cheese, yogurt, beer, or soy sauce also depends heavily on non-volatile substances (i.e. things you can’t smell). Some of the most important compounds that fall under this category are fragments of (originally-long) proteins broken down by bacteria during fermentation of milk or grains.

Still, there’s a lot of these fragments out there — over 1000 have been documented to impart flavor in fermented-milk products alone. Even worse, they take a whole lot of time and effort to discover. To work around the issue, a team led by Thomas Hofmann, head of the Chair of Food Chemistry and Molecular Sensory Science at TUM, has developed a new method to discover these tasty bits.

The team combined existing methods of proteome (protein) research with methods of sensory research to quickly and efficiently identify the most flavorful protein fragments in a given sample. The team tested their procedure on two varieties of cream cheese — which had different degrees of bitterness. The goal was to identify exactly which protein fragments gave the cheeses their bitter off-taste.

“We coined the term ‘sensoproteomics’ for this type of procedure,” said Andreas Dunkel from the Leibniz-Institute for Food Systems Biology, lead researcher for the study.

An initial review of the literature on the subject told the team that there would be roughly 1,600 different protein fragments that could create a bitter off-taste in dairy products. Chromatography-coupled mass spectrometer analysis in tandem with computer simulations narrowed the search down to 340 potential candidates. Comparative spectrometric, sensory, and quantitative analyses further reduced the number of fragments responsible for the bitter cheese flavor to 17.

“The sensoproteomics approach we have developed will, in the future, contribute to the rapid and efficient identification of flavor-giving protein fragments in a wide range of foods using high-throughput methods—a significant help in optimizing the taste of products,” says Prof. Hofmann.

The paper “A New Approach for the Identification of Taste-Active Peptides in Fermented Foods” has been published in the Journal of Agricultural and Food Chemistry.

Fat is recognized as the sixth basic taste, but it’s awful on its own

Distilling tastes and flavors to their most basic constituents is essential to making food the tastiest it can be. We currently know of five basic tastes: sweet, sour, salty, bitter and the somewhat hard to pin down umami (think savory or anchovies, tomato juice, the likes). Now, a group claims it has pinned down the sixth: fat. Bacon lovers throughout the world might rejoice at the news. However, if you like bacon you should feel grateful you didn’t take part in this study because isolated fat molecules are reportedly awful tasting. Distinct yes, but quite awful. In fact, to distinguish from what people generally refer to as “fat”, the researchers at Purdue University propose a new term to describe the sixth basic taste: oleogustus.

oleogustus

The inside of the mouth is littered with taste buds, each with 100 or so receptors that chemically bind with the food and send a signal to the brain. This signal is what we eventually perceive as a taste or flavor. The most taste buds are found on the tongue, but you’ll find other buds on the throat, top, bottom and side of the mouth. The average person has around 10,000 taste buds in their mouth and throat. The peak is hit in childhood then these progressively wither as you age. The older you get, the less better you’ll be at discerning the various tastes and flavors found in the food you ingest.

Though there are a myriad of flavors and tastes, these can be broken down to a couple of basic tastes. Similarly to how the primary colors (yellow, blue, red) can be combined to rend other colours, so can basic tastes combine in various degrees to form new flavors. Taste is a bit more complicated than sight though, and a lot more subjective. “There is no accepted definition of a basic taste,” said Michael Tordoff, a behavioral geneticist at the Monell Chemical Senses Center in Philadelphia. “The rules are changing as we speak.”

So, the jury is definitely not done with what constitute the basic tastes, but scientists are working it out. For good reasons, too. Understanding vision and how colours work is essential to the latest display technology like smartphones or LED TVs we all know and love. Similarly, the food industry can use molecular interactions to make food tastier or come up with new flavors altogether. Pinning down what the basic tastes becomes quite important in this context. So far, there are six such basic tastes, the latest one being oleogustus.

To confirm fat as the sixth basic taste, Richard Mattes, a professor of nutrition science at Purdue University, offered more than 100 participants isolated solutions which contained one of the six tastes: sweet, sour, salty, bitter, umami and fat (nonesterified fatty acids). The participants were asked to group each solution they sampled in a group. They had no problem grouping three basic tastes:  sweet, sour and salty. The rest were a bit ambiguous to the participants. So, most grouped the rest of the samples into one large group that served as a stockpile for all that is weird, gross and essentially awful (even bitter and umami taste terrible when isolated).

Elucidating further, the researchers made a new experiment with another group of participants. This time, only three isolated tastes were offered. This time, the participants easily divided the solutions into three distinct tastes, as expected. While there was some overlap with the solutions for sour and umami tastes, the majority of people were able to identify oleogustus as a taste distinct in itself, as reported in Chemical Senses.  

“There isn’t a firm agreement about what characteristics are necessary, but we have a pretty solid sense,” said Mattes. “We just needed to prove that it produced a sensation that was unique from the other primary tastes.”

“Understanding this could have huge implications for the food industry,” said Mattes. “It could make a lot of food taste a lot better.”

What about the seventh or eighth basic taste? Well, there may be other candidates as well. These include metallic (self explanatory), piquance (the burn you feel on your tongue from peppers), coolness (minty and fresh sensation from peppermint or menthol) or carbon dioxide (the zingy fizz you get from soda, beer, champagne and other carbonated beverages).

Penguins Have Pretty Bad Taste, Genetic Study Shows

Penguins really have bad taste – they can’t detect the savory taste of the fish they eat, and they also can’t enjoy fruits or sugar. Penguins have lost their ability to taste everything else other than salty and sour.

n Adelie penguin photographed by Herbert Ponting on the Terra Nova Expedition to the South Pole. Photograph: Popperfoto/Popperfoto/Getty Images

Humans (and most vertebrates) have five basic tastes: sweet, sour, salty, bitter and umami. In case you’re wondering about the last one, umami is the savory meaty taste. While the loss of taste is very intriguing, the loss of the umami taste is especially perplexing because penguins are fish eaters. Study leader Jianzhi “George” Zhang, a professor in the U-M Department of Ecology and Evolutionary Biology said:

“Penguins eat fish, so you would guess that they need the umami receptor genes, but for some reason they don’t have them,” says Jianzhi “George” Zhang of the University of Michigan. “These findings are surprising and puzzling, and we do not have a good explanation for them. But we have a few ideas.”

Image via Science News.

This is highly unusual. While no birds can taste sweet, most are capable of perceiving umami and bitter notes – especially the carnivorous ones… but not penguins. Since the loss of taste appeared in all penguin species, it seems likely that the change was actually done by the penguins’ ancestors.

“Taken together, our results strongly suggest that the umami and bitter tastes were lost in the common ancestor of all penguins,” write Huabin Zhao and colleagues.

It’s not clear why this happens, but it likely has a lot to do with the extremely cold environments in which the penguins live. The taste receptors for sweet, umami, and bitter tastes are temperature sensitive – they don’t really work well when it’s extremely cold. So even if penguins had them, they wouldn’t perform adequately, so they likely faded away in time. Also, penguins tend to swallow their food whole, so they likely don’t care that much how it tastes like.

“Their behavior of swallowing food whole, and their tongue structure and function, suggest that penguins need no taste perception, although it is unclear whether these traits are a cause or a consequence of their major taste loss,” Zhang says.

Penguin tongues are also strange from other points of view, the study observes. Some penguins lack taste buds altogether; the tongues are instead covered with stiff, sharp papillae covered by a thick, horny layer. The tongue has lost its tasting potential, but instead, it became better at catching and trapping prey.

Journal Reference:

  1. Huabin Zhao, Jianwen Li, Jianzhi Zhang. Molecular evidence for the loss of three basic tastes in penguins. Current Biology, 2015; 25 (4): R141 DOI:10.1016/j.cub.2015.01.026

 

obesity taste

Obese people have poorer sense of taste, study shows

Previously, it’s been shown that obesity can cause changes in the brain, leading some people to over eat food high in saturated fat and refined sugar, as well as cause poorer memory. A new study published by researchers at University at Buffalo found a new physiological trait that can become altered as a result of obesity. Their findings suggest that obese mice have particularly less sensible taste buds than their lighter brethren, and react more poorly to sweets suggesting that obese people may need to ingest more sweets than would be required in normal conditions to get the same sensory bang.

obesity taste

(c) foodnavigator.com

Taste may actually be the most complicated sense, as researchers know less about how this sense works than hearing or sight for instance. This may be because taste is strongly connected with emotions, as various stimuli like bitter, sweet or sour elicit various emotional responses: pleasure or displeasure in various degrees. This makes sense from an evolutionary perspective as taste often was the first barrier between us and food that may be unsafe to eat. It also acts as an incentive driver – ever wondered why meat or sweets taste so good? It’s because these high energy foods would have been vital for survival not too long ago, and to make things easier the brain  developed a pleasure or reward response to eating high fat and sugar foods. Of course, now that we live in a time of abundance there’s no need to stack up and eat all the fat you can before a predator reels in from behind, faced with the choice, however, a lot of people fall into the trap of overeating.

The taste of food is picked-up by taste buds, most of which are located on the tongue. A typical adult has between  2,000 and 4,000 taste buds, while each bud has  between 10 and 50 sensory cells.  These cells form a capsule that is shaped like a flower bud or an orange. At the tip of this capsule there is a pore that works as a fluid-filled funnel. This funnel contains thin, finger-shaped sensory cell extensions, which are called taste hairs. Proteins on the surface bind chemicals to the cell for tasting. The actual sense of taste itself is relayed to the nervous system through several cranial nerves.

The researchers compared 25 mice obese mice that were fed a high-fat diet to 25 normal weighing mice.  To measure how each animal responded to various taste stimuli, the researchers looked at the calcium signaling process that occurs in taste cells. For each kind of “taste” there’s a certain calcium level associated to it which can be measured. The researchers found that in obese mice there were significantly fewer taste cells that responded to sweet stimuli, and as if this wasn’t enough it was also found that those that responded had a weaker response than usual.

“Obesity can lead to alterations in the brain, as well as the nerves that control the peripheral taste system, but no one had ever looked at the cells on the tongue that make contact with food,” said lead researcher Kathryn Medler. “What we see is that even at this level – at the first step in the taste pathway – the taste receptor cells themselves are affected by obesity.”

It was hypothesized before that obese people have a less sensitive taste than thinner people, but this is the first study that has evidence to back this idea up, albeit the research is on mice. Medler and colleagues suspect that this lack of sensitivity might encourage people to over eat just to get the same amount of taste response or pleasure reward, adding further weight to an already vicious cycle.

“If we understand how these taste cells are affected and how we can get these cells back to normal, it could lead to new treatments,” Medler concluded. “These cells are out on your tongue and are more accessible than cells in other parts of your body, like your brain.”

Findings were documented in a paper published in the journal PLOS ONE.

wine tasting

Why you shouldn’t choose wine based on what critics voice, study backs-up

What are the differences between a bottle of premium, high rated Pinot Noir and a shelf classic Merlot? Well, besides a lot of money, wine critics would be quick to detail all the subtle differences that come together in an amalgam of sensations, and consequently make the premium look like a divine gift from Dyonisis himself. For the rest of us mortals however, these differences might often not be felt, other than a lighter wallet. A recent study published in the American Journal of Enology and Viticulture comes to the conclusion that top wine critics have the ability to taste subtle flavors and chemicals that allude the masses, offering them an inherent biological advantage. In short, top wine tasters sense wine much differently from you or me would, so you shouldn’t care.

wine tastingWith this is mind, is it worth then spending a lot of money on top wine brands, whose prices are directly proportional with the critics’ ratings, only to notice some mild refinements compared to your typical $10 shelf wine? It’s a very interesting question. It’s more interesting, however, how wine critics have managed to persuade the drinking masses along the years into believing what’s a good wine and what isn’t. Same thing applies to movies, music and so on. I feel the discussion is escalating a bit, so back to the study at hand.

The Penn University researchers, who conducted the study, tested a group of top critics to see if they could detect the presence of a certain bitter chemical. Most of them did, compared to a trifle of the common folk, and moreover they described the experience as intensely bitter. Apparently, wine writers, winemakers and wine retailers were about 40 percent more sensitive to the bitterness than casual consumers of wine.

“What we found is that the fundamental taste ability of an expert is different,” says John Hayes of Penn State.

This has lead many to state that their ability is biological in nature, and thus it’s simply all a matter of some people being particularly gifted with an uncommon sense of taste. However, there are a lot of people who were keen to claim that it’s equally a matter of experience, as well.

A separate study published in the American Association of Wine Economists found that there is a direct correlation between the degree of satisfaction a customer feels after buying a bottle of wine and the price payed for it. When faced with tasting unlabeled wine, however, most consumers seemed to enjoy expensive brands just as much as regular wine. The power of suggestion at works.

“If you think the wine is supposed to be good, you’re going to enjoy it a lot,” Hayes said. “But to me the simplest rule in wine is if you like it, drink it,” said Hays.

Does expensive beer taste better ?

It never ceases to amaze me how placebo works when it comes to prices – most people tend to be greatly influenced by the price of an item they buy, when it comes to judging its quality. Believe it or not, it has even become a marketing strategy, to raise your price rather than lowering them, to attract clients.

Sounds like a joke, right ? Well sadly, this kind of strategy often works, and the public is perversely tempted into a more expensive product, exactly because it is expensive; basically, you expect the more you spend for something, the better it is.

In this amusing video, Professor Funk takes a look at how people judge a beer based on its price. Watch it, and wait for the twist – it will definitely be worth it, and you’ll find out why it’s better to get cheap beer for your friends.

He also briefly describes other really really interesting studies – which I highly recommend watching before you go to the supemarket.

Via Guardian