Mind & Body

Learning to Like Bitter Flavors Isn't Just in Your Head — It's in Your Saliva

Kids generally hate coffee, but somewhere along the line, most of us learn to love it. Same goes for dark chocolate. And IPAs have been the reigning monarchs of the craft beer world since the early 2000s, despite the fact that it's much cheaper to simply chew on a pinecone wrapped in a dirty sock. Still, some people clearly appreciate the flavor. And thanks to the SPIT Lab, we know exactly why. Spoiler alert: There's a pretty big clue in the name of the research facility.

Related: How Taste Works

Saliva-n' It Up

As much as this author might hate them, a lot of people seem to like the bitterest beers. Likewise, dark chocolate, red wine, and black coffee are all wildly popular foods with a distinctly bitter flavor. According to a new report from Purdue's SPIT lab, even those of us who prefer crisp pilsners and rich stouts might benefit from trying more IPAs. In time, the bitter flavors can actually change the way we experience taste.

You've probably had the experience of tasting something that slowly grows on you. Actually, there's some pretty good evidence that everyone develops an ability to enjoy bitter food more as they get older, with children being especially sensitive to it. There's a reason why kids notoriously despise eating their greens. But Dr. Cordelia Running, the director of the lab, wanted to explore the actual mechanism for that transformation.

See, saliva isn't just what keeps your tongue moist; it's the biochemical medium of the mouth. That means that every chemical reaction that happens between your tongue and teeth is carried out against a backdrop of saliva. Dr. Running and her team decided to take a closer look at the mouth's most faithful companion.

Bitter foods like dark chocolate get their biting taste from chemicals known as polyphenols, and Running's team suspected that learning to like these flavors comes from being better able to process these chemicals. To test their theories, Running's team recruited 64 participants to start on an alternating weekly diet set to last six weeks: one week they'd give up bitter food altogether, the next they'd be asked to consume three glasses of polyphenol-rich chocolate almond milk per day. Just as the team hypothesized, participants who were in the chocolate-consuming part of the cycle began naturally producing a new kind of protein in their saliva — one that easily binds and captures those polyphenols. At the same time that this protein began to show its face, the participants reported that they enjoyed the drink more and experienced it as less bitter or astringent.

SPIT Shines a Light on Taste

We know, we know. By this point, you're asking yourself how we could have possibly gotten this far in the article without addressing the fact that all of this info comes from the SPIT Lab. Yes, it's a great name. Yes, it's very descriptive. And no, this examination into the experience of bitterness isn't the only significant work to have come out of it. The lab does a lot of work on saliva, but that's not all. SPIT Lab is short for Saliva, Perception, Ingestion, and Tongue Lab, and their focus is on all of the ways the mechanics of the mouth can alter the experience of eating and tasting.

Another experiment known as the desensitization test is one of the more interesting projects to have come out of the lab. The team wanted to dive into the experience of eating spicy and bitter food, so they fed a group of participants a combination of bitter seltzer water and chili-oil-spiked ginger beer — either they would drink one then the other, or two of the same. They found that sensitization absolutely did not occur, meaning that taking in more spiciness did not make the next spicy drink taste even hotter, and a similar effect was seen with the bitter drink. One spicy beverage did, however, make the next one taste milder. Perhaps most surprisingly, a drink of the spicy ginger beer made the bitter seltzer water taste that much more bitter, likely because of the contrast between the two flavors. So if you really want to revel in the fingernail-curling hops of your local brewery's next release, load up on hot sauce first. (If you'd rather tone it down, however, add some salt).

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Maybe we've been too hard on the IPA. Here's Joshua Bernstein's "The Complete IPA: The Guide to Your Favorite Craft Beer" to make up for it. We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.

Written by Reuben Westmaas November 14, 2018

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