Chewing the fat: USU prof analyzes taste of substance
The human tongue has the ability to detect sweet, salty and bitter tastes. But what about fat?
According to a Utah State University study conducted by Tim Gilbertson, people can taste fat.
“The role of taste is to detect the things we need to survive,” Gilbertson said. “Fat is absolutely necessary for us to survive. It is the most energy-dense nutrient there is.”
It has long been thought that fat had no taste, rather it only provided texture for the food people eat, Gilbertson said. One example of that idea would be the slipperiness it gives to ice cream.
This idea was first challenged in 1998 while Gilbertson was working at Louisiana State University. An abstract was presented to one of his undergraduate students which introduced the idea of putting fatty acids on animal taste receptor cells to see if taste could be detected.
The project continued at USU when Gilbertson moved here in 2000.
At USU the focus has been on understanding taste transduction, and taste receptors on the tongue, said Gilbertson’s undergraduate assistant Jeremy Guenter, a senior majoring in liberal arts and sciences.
As fatty acids were placed on the taste receptors, the taste system responded. The response was especially strong to the fats humans need to survive – polyunsaturated fat acids. The conclusion was a resounding yes, people can taste fat, Gilbertson said.
In studying the animals’ reaction to the fat, it has been theorized that those who eat a lot of fat, tend to be less-responsive to it. They eat until they’re tired of eating. These were the rats that were more obese. Those that eat less fat are more sensitive to it, so they stop eating much sooner. These rats tended to be leaner, Gilbertson said.
Some rats liked the taste of fat, and some clearly didn’t. Those that did, were put on a typical western diet that was high in fat. Most of these rats became obese. However, some of the fat-eating rats also stayed lean.
Different bodies react to fat differently, Gilbertson said.
The same receptor that is located on the tongue and can detect the taste of fat is also located in the pancreas, small intestine, and liver. Research has also begun into these areas, and how they are affected by fat.
But why is this an important discovery? According to research done by the nonprofit group Research Triangle Institute International and the Centers for Disease Control and Prevention that was released last week, in the United States alone more than $75 billion a year are spent treating obesity and obesity-related health disorders.
Taxpayers are responsible for about $39 billion of the bill.
“We need to recognize the problem, and recognize that fat is a huge part of that problem,” Gilbertson said.
Fat substitutes have been used, and still are being used in the food industry. Olestra used in Wow! potato chips is one example.
Gilbertson said that Olestra, however, was created with the belief that fat had no taste. Many people recognize that the Olestra chips don’t taste as good as “fatty” potato chips.
This could also be that “fat is very good at accentuating the taste of salt and sugar,” Gilbertson said.
“Hopefully we can design fat substitutes that are more acceptable to the consumer,” Gilbertson said.
Currently there are other flavor substitutes that the public has accepted.
Sugar, for example has long been substituted with NutraSweet. Now that fat has a recognized taste, the goal is to be able to find healthier substitutes for it. Questions have also been raised as to whether or not medications could increase a person’s sensitivity to fat. If so, would that sensitivity help in reducing obesity? Researchers also don’t know if a person can become desensitized to fat.
“We do know that if you feed children a lot of fat, they tend to be predisposed to obesity,” Gilbertson said.
Now that the taste of fat has been discovered, answers to these questions and more could lie in the near future.
-apassey@cc.usu.edu