“A lot of our modern lives is geared toward issues related to food, but what we ultimately care about is how food tastes” says Robin Dando at Cornell University. (Photo Credit: Dave Burbank)

The Link between Taste Buds, Obesity, More

by Caitlin Hayes

Humans have about 10,000 taste buds, tiny organs with 50 to 100 receptor cells in each. These receptors — for salty, sweet, bitter, sour, and savory — are responsible for our rich sense of taste, a sense that’s deeply connected to our emotions. Because our sense of taste also impacts the foods we choose, it is directly linked to our quality of life and our overall health.

Photo Credit: Dave Burbank

Robin Dando, Food Science, works to understand the mechanisms of taste and how the structure of the taste buds leads to and varies our perceptions of the foods we eat. “A lot of our modern lives is geared toward issues related to food, but what we ultimately care about is how food tastes,” Dando says.

Many conditions seem to alter our taste buds and affect our ability to taste — such as inflammation and obesity or even overexposure to certain foods. What effect do these changes in our taste buds have on our perceptions and our behavior? “I’m particularly interested in metabolism, how obesity and other aspects of metabolism can influence how we perceive foods,” Dando says.

Damaged Taste Buds and Obesity

In research funded by the American Heart Association, Dando and his lab have found a link between obesity and damaged taste buds in mouse models. These damaged taste buds lower the sensitivity to taste in obese mice. “We think this is a really big result,” Dando says. “If how we perceive foods changes when we become obese, that could start to direct us to more unhealthy foods, which would be another factor in why obesity is such a difficult problem.”

Dando is now working to see if the results his group found in mouse models can be replicated in humans. In one study, his lab tracked a population of Cornell students over the course of their freshman year, a prime time for weight gain. “Most people did gain a little bit of weight — not very much but enough to see some changes in taste,” Dando says.

Males, in particular, lost some taste function associated with weight gain, and their sense of umami, or savory flavor, became less intense. Dando thinks the latter may be because of an increase in meat consumption in males. Another result was that everyone in the study, regardless of gender, lost some sensitivity to salt. Dando suggests this is due to overstimulation. The food in the dining halls and at restaurants is going to be typically saltier than home-cooked meals.

“We think this exposure to salty foods, for almost a whole year, has just blunted everyone’s taste slightly to salt,” Dando says. “Something like this has also been reported in other people’s work, in totally different study-designs. We think this represents something we should be a little careful of. Because if people are less sensitive to salt, maybe they’re starting to put more salt on their food, which isn’t good.”

“If we eat something that’s very sweet very often…there’s a good amount of literature that suggests…we can become less sensitive to sweet because we’re sensing it all the time.” (Photo Credit: Dave Burbank)

Maybe they don’t over-salt their food, though. Another question Dando asks in his lab is whether the weakening of the sense of taste actually changes behavior. In one study, Dando’s group designed an experiment where, over the course of four days, participants were given varying levels of a natural herb, Gymnema sylvestre, which blocks the sweet taste function. They were then assigned a series of tasks where they would make choices between foods with varying levels of sweetness.

“The ones who lost their taste function always went toward sweeter foods. We think this is probably because they’re not getting the positive feeling you associate with sweet-tasting foods.”

“The ones who lost their taste function always went toward sweeter foods,” Dando says. “We think this is probably because they’re not getting the positive feeling you associate with sweet-tasting foods. This backs up the idea that there could be real changes in behavior when people lose their taste.”

If obesity weakens the sense of taste, an overweight or obese person may compensate by choosing more intense tasting, and so often higher calorie foods. Dando’s group continues to investigate and validate this hypothesis. “The long-term goal with this research is to figure out how the taste buds contribute to obesity,” he says.

Conditions That Alter Taste Buds

Dando is also interested in how other conditions affect the taste buds, including inflammation, changes in the microbiome, and pregnancy. It seems like pregnancy, for example, alters eating habits. Accounts of strange pregnancy cravings anecdotally corroborate this. But how exactly are the taste buds altered? And what effect does a mother’s diet have on her child’s sense of taste? Dando’s group is currently working with mouse models to answer these questions.

“There’s some evidence that when we eat a certain thing during pregnancy, the child will then prefer that,” Dando says. “This is really interesting to look at because it suggests that our food preferences can be set before we’re even born, which also implies that there might be a window to set things on the right course, too.”

In other studies, Dando’s group is investigating how exposure to foods might affect our perceptions of other tastes. They recently found, for instance, that drinking caffeinated coffee makes us temporarily less sensitive to sweetness. They now have multiple studies looking into how the overabundance of a taste can affect behavior.

“If we eat something that’s very sweet very often, for example, there’s a good amount of literature that suggests that we can become less sensitive to sweet because we’re sensing it all the time. Does that then push us to consume other things that are more intensely sweet?” Dando says. “And can that cross over to our perception of other things? If we consume a lot of something that’s very sweet, does it influence how we perceive alcohol, for instance? Does the very sweet food change our behaviors related to that as well?”

In past research, Dando has also looked at how the sensory environment has impacted taste function. His group found, for instance, that the loud noise on airplanes dulls the sense of sweet but elevates umami, the savory taste found in meats and soups and also tomato juice. This may account for why tomato juice is such a popular choice from the beverage cart. The research may also guide airlines toward offering more appetizing foods.

From Physics to Studying the Sense of Taste

The applicability of Dando’s research to everyday life is no accident, but it’s also not where he started. He earned his PhD in applied physics, researching how ion channels, transporters, and receptors work. “I found it a little too conceptual,” he says. When he was looking at postdoctoral opportunities, he wanted to study something that could have more direct impact on people and behavior.

“I got really interested in studying the same things from my PhD but in a system we can all relate to, which is taste. Taste buds are something we’re all intimately connected to,” he says. Dando moved to a lab where he researched the neuroscience of taste, how the signals are transmitted from the taste buds to the brain.

With a background in physics and neuroscience, Dando’s home in the Department of Food Science is somewhat unusual. While researchers in food science do study the senses, the end goal is usually to understand aspects of food itself. “I think Food Science at Cornell is open to a more novel approach,” Dando says. “Rather than the foods people are eating, I would classify my research as studying the people who are eating the foods.”

Originally published on the Cornell Research website. All rights are reserved in the images. If you’d like to reproduce the text for noncommercial purposes, please contact us.

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