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Dr. Wendy Sue Universe

Dear Dr. Universe,

Why are carrots orange?

— Caden, 11, N.C.

When you picture the carrot section at a grocery store in the United States, you probably imagine rows of orange. But carrots can come in a rainbow of other colors: purple, yellow, red and more.

And the first carrots weren’t orange at all. They were stark white.

That’s what I learned from Tim Waters, a vegetable specialist at Washington State University-Extension. He studies how to grow different kinds of vegetables, and helps others learn how to grow them, too.

Carrots you eat today are domesticated. Domestication happens when humans tame wild plants or animals for many generations. Over a long period of time, people bred the carrot ancestors for traits such as sweet taste and attractive color.

Domestication helps explain how wolves became dogs, and how teosinte became maize. It’s also how a wild white root became sweet and orange.

“Before carrots were domesticated, they were believed to be white and very bitter and woody,” Waters said. “When people began domesticating them, the first types that were bred and fed upon by humans were purple and yellowish in color.”

Scientists think people first domesticated carrots in Central Asia around 1,100 years ago.Even though the first carrots weren’t as sweet as the ones you eat today, people probably weren’t eating the roots.

“It’s known that carrots were first grown primarily for seed and the uses of leaves,” Waters said.

But as more colors emerged, the roots became tastier and became the more valuable part of the carrot.

We don’t know exactly when the first orange carrots appeared. But we have a good idea of why that color stuck around—simply because humans liked it.

“Orange wasn’t a naturally occurring color. It was kind of a genetic flaw, and then it was selected for,” Waters said.

One story says orange carrots became popular in the Netherlands in the 1600s. Orange became the national color, so orange carrots were supposedly associated with the royal family and William of Orange. But orange carrots probably weren’t bred by the Dutch. They just became more popular there.

Over time, orange carrots became the most common variety in some parts of the world. “That’s really why, in Western society, everybody perceives carrots to be orange,” Waters said. But that orange color isn’t just for looks.

Orange carrots are packed with chemicals called carotenoids — specifically, beta-carotene. Your body turns beta-carotene into vitamin A, which helps you grow and protects you from getting sick.

Beta-carotene isn’t just nutritious. It’s also loaded with orange pigment. That’s why vegetables with lots of beta-carotene—like sweet potatoes, squash, and pumpkins—share the same color.But what about that rainbow of other carrot colors? They have their own special qualities, too. Purple carrots get their color from loads of anthocyanin, a chemical that is healthy for your heart.

Carrot breeders have even created carrots with multiple colors. You can get the best of both worlds: a carrot that’s orange on the inside, purple on the outside!

Have a science question? Ask Dr. Wendy Sue Universe, WSU’s resident science cat and writer, by email at Dr.Universe@wsu.edu.

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