Love Carbs? Scientists Discover a Sixth Sense That Explains Humans' Preference for Starchy Food

A new study has revealed that after umami, the human tongue now has a sixth sense which could explain why humans love carbs so much.

According to the study published in the journal Chemical Senses, food rich in carbohydrates could produce a distinct "starchy" flavor that's different from sweet, sour, salty, bitter and umami. Juyun Lim from Oregon State University in Corvallis explains that for so long, scientists have not considered the idea of humans specifically tasting carbohydrates.

“Every culture has a major source of complex carbohydrate. The idea that we can’t taste what we’re eating doesn’t make sense,” Lim said via New Scientist.

Complex carbohydrates could be broken down to short chains of sugar molecules; thus, scientists have categorized starch's taste based on these sweet molecules. However, to prove that starch has a unique flavor separate from sweetness, Lim and her team gave different carbohydrate solutions to participants that vary in race. The participants were also given a compound to block the sweet receptors in the tongue.

Results showed that the test subjects detected the starch flavor despite the sweet receptor block. Asians described it as being akin to rice while Caucasians described the flavor as "bread-like or pasta-like." This suggests that humans could taste starch even before it's broken down to sugar molecules.

The participants were also given a compound to block the enzyme that breaks carbohydrates to shorter ones. After the compound was given, the subjects were unable to taste the starch flavor, proving that the distinct flavor from starch comes from short carbohydrate chains.

“Many people think there are only five tastes, but a bunch of us think there might be others,” said Michael Tordoff at Monell Chemical Senses Center in Philadelphia.