Yes, carrots can turn you orange. Here's how many it takes

This one sounds like something a parent invents to stop you finishing the bag. It's real, though. The name for it is carotenoderma, and DermNet, the dermatology reference, describes it as a benign yellow-orange discolouration of the skin.

How many carrots?

Dr Melissa Piliang, a dermatologist at Cleveland Clinic, gives a usefully concrete number: about 20 to 50 milligrams of beta-carotene a day for a few weeks. A medium carrot has about 4 milligrams. That works out at around ten carrots a day, every day, for weeks. Occasional carrot enthusiasm won't do it.

Other orange and yellow vegetables carry beta-carotene too, and one medical report describes the same thing happening with a diet rich in red palm oil. Carrots are simply the famous example.

Where the colour goes

Beta-carotene is the pigment that makes a carrot orange. Your body converts it into vitamin A, but only up to a point, and it regulates that conversion strictly. This is why eating a mountain of carrots turns you orange without giving you vitamin A poisoning.

Whatever isn't converted stays in the blood and ends up in the skin, mixed into the oily, fat-soluble outer layer called the stratum corneum. That layer is thickest on the palms and the soles of the feet, so that's where the colour shows first, along with the nose and the creases beside it.

Picture a glass of orange juice and some kitchen paper. A single sheet barely picks up colour, and a thick wad looks properly orange. It's only a picture of "more layer, more colour". Your palms don't work by absorbing juice.

How to tell it from something that matters

This is the part worth remembering. Carotenoderma doesn't affect the whites of your eyes, since they don't have that outer layer of skin. DermNet uses this to distinguish it from jaundice, which does turn them yellow.

So: orange palms, normal eyes and a confession about your diet is probably carrots. Yellowing of the whites of the eyes isn't, and it's a reason to see a doctor promptly.

The colour itself needs no treatment. Reduce the beta-carotene and it fades, although it can take several weeks or months.

What flamingos have to do with it

Flamingos hatch with grey down. They get their pink from carotenoid pigments, the same family as beta-carotene, in the algae and tiny crustaceans they eat. Zoos know this perfectly well, and San Diego Zoo feeds its birds a special pellet diet to keep them in the pink.

What happens if you take the pigment away? It's tempting to say a flamingo would turn white, but keepers from the Zoological Society of London told IFLScience that the birds would become very pale, not white.

The two cases aren't identical, but they rhyme: an animal's outside can report what it has been eating.