Safety[edit]
The red colour compound betanin is not broken down in the body, and in higher concentrations may temporarily cause urine and stool to assume a reddish colour; in the case of urine this is called beeturia.[15] This effect may cause distress and concern due to the visual similarity to what appears to be blood in the stool, hematuria (blood in the urine), or hematochezia (blood passing through the anus, usually in or with stool). These deceptive appearances are completely harmless and subside once the betanin is out of the system. In the cases of reddish feces, the bright redness from betanin is in contrast to what occurs with melena (very dark or blackish feces) which often indicates that bleeding is occurring further up the digestive system, and is more likely to be a serious problem.
Nitrosamine formation in beet juice can reliably be prevented by ascorbic acid.[16]