[IzzieC (OP)]

Aidan asks,

"Consuming orange carrots in high excess can turn your skin orange, because of the beta-carotene. What about purple carrots?"

What do you think?

[Bored chemist]

The most likely outcome is that it would turn your urine purple (or red or blue depending on pH)

[evan_au]

In some people, eating excess beets/beetroot will turn urine or feces purple.
https://en.wikipedia.org/wiki/Beeturia

[Kryptid]

It probably wouldn't. Orange carrots get their color from carotenoids whereas purple carrots get their color from anthocyanins. Anthocyanins are apparently metabolized and excreted rapidly from the body. Interestingly enough, purple carrots actually have more carotenoids than orange carrots, so you could well turn orange from eating too many of them instead.

[Bored chemist]

In some people, eating excess beets/beetroot will turn urine or feces purple.
https://en.wikipedia.org/wiki/Beeturia

Yes, but beets have a different set of colours to them.
https://en.wikipedia.org/wiki/Betalain
Rather than
https://en.wikipedia.org/wiki/Anthocyanin

The anthocyanins are more extensively metabolised, but some still gets into the urine.
(About 5% in this study)
https://www.ncbi.nlm.nih.gov/pubmed/16861803

[syhprum]

As a child I used to take Do Do tablets to relieve asthma I understand the active  ingredient was Ephedrine the tablets were orange and they turned my urine green (I knew they were working when that happened!)

[katieHaylor]

This question has now been answered, and you can listen to it here: https://www.thenakedscientists.com/articles/questions/does-eating-purple-carrots-turn-you-purple