What makes carrots orange? Scientists discover the answer

Researchers studied the genetic blueprints of more than 600 types of carrots to try and solve the mystery of their colour
PA
William Mata29 September 2023

They may not make you see in the dark, but researchers have discovered a truth behind another legend of the carrot: what makes them orange.

Scientists at North Carolina State University studied the genetic blueprints of more than 600 types of carrots to try and get to the bottom of the age-old mystery of their colour.

And lead researcher Massimo Iorizzo thinks his team has cracked it.

He told New Scientist that carrots were purple, yellow and white in the 10th century but crossing the yellow and white led to an orange shade coming to Europe in the 14th century.

Three genes, he said, are needed to make carrots orange. But strangely, these cannot be the dominant genes and instead need to be recessive or turned off.

Dr Iorizzo said: “Normally, to make some function, you need genes to be turned on.

“In the case of the orange carrot, the genes that regulate orange carotenoids – the precursor of vitamin A that have been shown to provide health benefits – need to be turned off.”

Vitamin A is a major health benefit of carrots and can help improve vision, meaning there is some truth in the adage that eating them can help you see in the dark.

Put in layman’s terms, the carrots produce more of this health benefit when they are orange compared to when they were purple or white. It appears their prominence on supermarket shelves came about because they were preferred for their aesthetic merits or because their taste was preferred. And as knowledge grew of their health benefits they became more popular still.

“This study basically reconstructed the chronology of when a carrot was domesticated and then the orange carrot was selected,” Dr Iorizzo said.

Fans of Jannik Sinner dress as carrots at Wimbledon
PA

Can carrots make you turn orange?

Eating many carrots can indeed make your skin turn orange but this is a harmless phenomenon caused by the beta-carotene nutrient found in the vegetable.

Beta-carotene is also found in apricots, cantaloupe melon, mangoes, oranges, pumpkin, squash, sweet potatoes and yellow peppers.

It is a harmless trope and the colour will fade. It differs from person to person as to how much beta-carotene you would need to consume to turn orange.

May Simpkin, a health website, states: “If you’re worried, the typical areas where you’ll see changes in skin colour first are areas of thicker skin like palms, soles, knees, elbows and also folds around the nose. Simply reduce the amounts of the foods you are eating and the discolouration will fade and return to normal.”

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