When I look in the toilet the morning after I have beets, I almost have a heart attack. Do you know what I'm talking about? This might be too much information, but my number 1 and number 2 are red! During the moment where I've forgotten that I had beets the day before, I think I am in trouble. But then it goes away. I am not recommending self-diagnosis through the Internet, but I'll share what I've found out about this.
About 10 to 14% of people get red pee after they eat beets. The rest of you might think this is just crazy talk, but it actually has a name—beeturia. It looks more fuchsia coloured than something bloody. This phenomenon may be more common in people with higher iron absorption, but that is still being investigated. It seems to have a genetic component, but does not seem to be a simple, one gene situation.
It Gets Beta
The colour comes from a kind of betalain pigment. Betalain comes from the Latin scientific name for beets, Beta vulgaris. The red to violet kinds of pigments are called betacyanins. The important one in beets is called betanin.
The betanin is sensitive to pH, so you can do important things with it like using beets to reveal a secret message written with a baking soda (basic) solution.
A strong acid, like that in the stomach of most people, breaks down the betanin pigment, while a weak acid, like the vinegar in which beets are pickled, or oxalic acid, which occurs in the small intestine, preserves the colour.
So maybe I have weak stomach acid. That does not seem to be catastrophic. The pigment just carries on to my small intestine, where the pancreatic juice is alkaline. Some bacteria in the intestines can also affect the breakdown of the pigment, but apparently mine are not doing much of that either. Judge me if you will.
In the Blood
The pigment passes into the large intestine where it is then absorbed into the blood stream. Two doctors reported an odd story of their son having a brightly coloured nosebleed that stained his hands. Beets were blamed for the colour, not the nosebleed. Kidneys remove the pigment and add it to urine.
Some of the pigment must keep going through the large intestine, because my poop ends up like red velvet cake.
Beeturia seems to be an under-studied subject. Perhaps I will contribute by searching the Russian literature for examples of characters who become unhappy in their own way, because they have had borscht and developed reddish pee.
In the meantime, perhaps you people can contribute to my pee poll by commenting on whether or not you see red after eating beets.