The human tongue has a sixth sense, and it loves carbs

You have a sixth sense.
You have a sixth sense.
Image: Reuters/Jason Reed
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The taste of carbs has a home on the human tongue.

Scientists have long recognized five types of taste buds on the tongue, used for sensing sweet, sour, salty, bitter, and umami flavors. A recent study by researchers at Oregon State University claims humans can detect a sixth flavor: starch.

Technically, the evidence shows we can taste some polysaccharides, including maltodextrin, which is derived from starch and used in lots of processed foods, including soft drinks, candies, potato chips, light peanut butter, and even supplement powders used by bodybuilders. The discovery adds to a growing body of research that suggests our ability to taste things is a more complex than once thought.

The Oregon State University team tested 100 people across five experiments on their ability to differentiate tastes. Scientists have long thought sweet taste buds were used to detect starch derivatives, but when they blocked those receptors, subjects reported they could still detect elements of glucose.

“From the evolutionary standpoint, the ability to taste starch or its oligomeric hydrolysis products would be highly adaptive, given their nutritional value,” the study says. The ability to taste the starchy flavor must be useful for humans, one of the researchers, Juyun Lim, told The New Scientist. His best guess: Starch makes for a valuable source for slow-release energy, and that’s worth detecting.

The idea of a sixth taste isn’t entirely new. Researchers at Osaka University in Japan published a study in 1994 showing rats were able to distinguish two types of carbohydrates: common sugars and polysaccharides, which are more chemically complex.