Noticing a change in stool color, particularly if it appears red, can be concerning. Red wine, along with other foods and drinks, can sometimes cause this temporary discoloration. Understanding common causes helps differentiate between a harmless change and a situation warranting medical attention.
The Role of Red Wine Pigments
Red wine derives its deep color from natural pigments found in grape skins, primarily compounds called anthocyanins. These pigments are a type of flavonoid. When red wine is consumed, these anthocyanins travel through the digestive system.
If large quantities of red wine are consumed, or if digestive transit time is fast, these pigments may not be fully broken down or absorbed. They can then pass into the stool and impart a reddish or darker hue. This effect is temporary and resolves once the wine is processed by the body.
Other Dietary and Harmless Causes of Red Stool
Beyond red wine, many other common foods and beverages can lead to a red or reddish-brown stool without medical concern. Foods with strong natural pigments are frequent culprits, as their pigments can remain undigested and alter stool color. For example, consuming beets can turn stools a reddish color due to their betacyanin content.
Cranberries, red food dyes in candies, processed foods, and drinks, along with tomatoes and tomato products, can also contribute to red or maroon-colored stools. These dietary changes are harmless and temporary, reflecting the passage of undigested pigments or dyes. Iron supplements and medications containing bismuth subsalicylate, like Pepto-Bismol, can also cause stools to appear dark or black.
When Red Stool Is a Concern
While dietary causes of red stool are benign, it is important to distinguish them from potential medical issues. Bright red blood in the stool, known as hematochezia, indicates bleeding from the lower gastrointestinal tract, such as the large intestine or rectum. Common causes include hemorrhoids or anal fissures, which are often not serious.
Darker, tarry black stools, known as melena, suggest bleeding higher up in the digestive system, such as the stomach or small intestine. This darker color results from digested blood. If red or black stool is accompanied by symptoms like abdominal pain, fever, weakness, dizziness, persistent changes in bowel habits, or unexplained weight loss, it warrants prompt medical evaluation. Any instance of blood in the stool, especially if the cause is unknown or it persists, requires discussion with a healthcare provider.