If you are a beetroot lover like me, you may have run into this problem. A visit to the restroom some time after eating a tasty beet leaves a scarlet trace.
The technical term for the presence of the red beetroot pigments in urine or stool is beeturia. Around 10 to 14 percent of the general population experiences this colorful surprise after eating beets.
Beeturia is thought to be mostly harmless, but it can be a sign of iron deficiency in some individuals.
So, what causes the red poop and pee? And should you worry when you experience it for the first time?
The red pigments in beets are called betalains. These strong antioxidants are present in each cell in the beetroot.
Precisely what happens to betalain in the human body is not clear. Researchers from the University of Edinburgh in the United Kingdom found a link between oxalic acid, which is a key component of most kidney stones, and beeturia.
They think that the red pigments are normally broken down in the stomach and colon. When oxalic acid levels are high, the red color is preserved and this can lead to red poop in people who do not normally experience beeturia.
Oxalic acid is present in many foods, including spinach, rhubarb, and cocoa powder. Eating these in combination with beetroot can therefore leave those not used to red poop with a surprising experience.
How beets cause red pee is not clear, but scientists speculate that those affected somehow fail to absorb the red pigments and excrete them in the urine and the feces instead.
Although the rate of beeturia is relatively low in the general population, it is significantly higher in iron-deficient individuals.
In those who are not currently being treated for their anemia, it can be as high as 80 percent, while the rate is around 45 percent in those currently receiving iron supplements.
In a case report in the Journal of Current Surgery, Dr. Zackariah Clement - from the Department of Surgery at the Canberra Hospital in Australia - explains, "Beeturia can cause unnecessary anxiety among patients and their families and can lead to expensive investigations."
If beeturia is your lifelong companion, as it is for me, you probably have nothing to worry about. But if you are experiencing it for the first time and are concerned about your iron levels or your health in general, it may be worth talking to your doctor.