Mind & Body

Loving Black Coffee Might Be Genetic — But for a Weird Reason

Some people guzzle black coffee all day; others prefer sugary soda, or a coffee frappé — also known as a low-key milkshake. Are these various types of drinkers different genetically? A new study suggests that yes, they are, but not in the way you'd think.

Drinks Make or Break Our Diets

A healthy lifestyle is all about diet and exercise, and what we drink is a big part of our diets. Since a sugary drink habit can torpedo otherwise healthy eating habits, scientists wanted to get to the bottom of why some people love sugary drinks more than others.

In the American diet, sugary drinks — including soda, lemonade, and sports drinks — are the single biggest source of added sugar and of calories, period. (Yes, even though the U.S. is home to a 1,794-pound cheeseburger!) This has major health implications; consuming a lot of sugary drinks heightens your risk of diabetes and heart disease, among other ailments.

This all means that figuring out (and combating) the allure of sugary drinks is a major public health issue. In a new study, published in May 2019 in Human Molecular Genetics, Northwestern scientist Marilyn Cornelis tried to do exactly that.

Specifically, she focused on whether a taste for Coke and Powerade was genetic. She predicted people who liked sugary drinks would have different taste genes than people who preferred their coffee black. Seems likely, right?

Likely ... but not quite true.

The Sugary-Drink Gene?

For her study, Cornelis and her team studied 336,000 people whose genomes were mapped out in the UK Biobank, an open-access database of detailed genetic and health information on roughly 500,000 British people.

Specifically, they asked study participants to track what they ate and drank for 24-hour periods, and coded the beverages they consumed as bitter or sweet. "Bitter" encompassed liquor, tea, coffee, and grapefruit juice; sweet included anything artificially sweetened and non-grapefruit juice. (Water was neither.)

Next, researchers looked for genetic markers that could predict a person's taste for sweet or bitter beverages. They found that a preference for coffee or alcohol was genetic and heritable — in other words, people could inherit these preferences from their parents. More surprisingly, though, the researchers found that people who preferred sugary drinks tended to have a variant of the FTO gene.

Here's why that's surprising: This gene variant not only corresponds with the absence of obesity; it also doesn't code for taste buds. (To be fair, neither do the genes that predispose people to like alcohol or coffee.) It's still a bit mysterious what the FTO gene does, but the current theory says that it impacts behavior, especially eating and activity habits.

Cornelis hypothesizes that instead of making sugary drinks taste better, the FTO gene variant dulls people's ability to enjoy the feelings of coffee and alcohol consumption, like a caffeine buzz or tipsiness after a few glasses of wine. As Cornelis put it in a statement: "People like the way coffee and alcohol make them feel. That's why they drink it. It's not the taste."

So if you hate the taste of black coffee, you're not alone. It seems possible that no one enjoys the taste of coffee or alcohol; they just enjoy the aftereffects. There's still more research to be done on whether bitter drinks actually taste good to some people, but it's possible that when we call coffee and alcohol "acquired tastes," we really mean you can acquire a taste for the sensations they create. The drinks themselves may never taste good.

Unless you get a coffee frappé, of course! Then it's sweet enough to make the bitter coffee palatable.

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For more on the science of flavor, check out "Taste: Surprising Stories and Science about Why Food Tastes Good" by Barb Stuckey. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Mae Rice May 22, 2019

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