Is it time to call fat a sixth taste?

Scientists are in consensus about the five basics tastes of sweet, salt, sour, bitter and umami. New studies are leading some researchers to call for adding fat to that list as a sixth taste. But while several scientists are promoting this idea, others remain skeptical, according to NPR’s The Salt.

It’s well known that humans can perceive fat as a texture. We can tell the difference between low-fat and full-fat versions of ice cream or cream cheese, for example. But whether this distinction can be thought of as a flavor isn’t clear. Researchers from Deakin University in Australia present the case for naming fat as a flavor in a recent paper published in the journal Flavour. They argue that “the next 5 to 10 years should reveal, conclusively, whether fat can be classified as the sixth taste.”

Russell Keast, a sensory scientist at Deakin and lead author of the paper, lays out the criteria for calling something a flavor. The key is in chemical reactions. Keast says that when a chemical substance like salt or sugar hits sensory cells in our mouth, it triggers a series of reactions from nerve cell to nerve cell which eventually reach our brain. Five criteria must be met to consider something a primary taste.

One criteria has been a sticking point: while people can immediately describe a sweet or sour component when it hits the tongue, they have trouble doing the same for solo fatty acids. Kearst says people will “say they know it’s different from water, but they don’t know why,” he says. “We don’t have any vocabulary to describe the sensation.” That validates the viewpoint of skeptics who think fat isn’t a separate flavor.

However, there is growing evidence that fat meets the other criteria, like producing downsteam effects on the body. The presence of fatty acids on our tongues may signal our digestive system to get enzymes ready to digest fat. They may also tell us to eat less because we’re about to get something rich in calories.

While some may think that the decision to call fat a flavor has more to do with semantics than science, others disagree. “If we recognize fat as a taste we could start developing better low-fat products,” says Richard Mattes, a professor at Purdue University. It could also change the way we fight the obesity epidemic. Mattes thinks that the science on how we perceive fat is rapidly evolving, and that “fat will be accepted as a taste soon.”

Do you think fat should be named as one of the basic tastes?

Photo of Lard from indexed blog Homesick Texan by Lisa Fain