Seeing red in your stool can be startling, but it’s often a harmless result of something you’ve eaten. Watermelon, a popular fruit, frequently causes this temporary color change due to natural pigments passing through your digestive system. Understanding why this happens can help you differentiate between a benign dietary effect and situations needing medical attention.
The Red Pigment Explained
The main reason watermelon can make your stool appear red is lycopene, a natural pigment. Lycopene is a carotenoid that gives many red and pink fruits and vegetables, including tomatoes and guava, their characteristic color. When you consume a significant amount of watermelon, your body may not fully break down or absorb all of the lycopene.
As a result, this undigested lycopene travels through the digestive tract and is excreted in the stool, imparting a reddish hue. This is a normal process, indicating the pigment is simply passing through your system. Watermelon’s high water and fiber content can also speed up digestive transit time, making undigested lycopene more noticeable.
Other Foods That Can Cause Red Stool
Watermelon is not the only food that can temporarily alter stool color to red. For instance, consuming large quantities of beets can lead to red or reddish-pink stool due to the pigment betanin.
Red food dyes, commonly found in items like red velvet cake, gelatin desserts, certain candies, and fruit-flavored drinks, can also pass through the digestive system and color the stool. Cranberries, red peppers, and even large amounts of tomato products like tomato soup or juice contain pigments that might cause this harmless color change.
Knowing When to Seek Medical Advice
While food-induced red stool is harmless, it’s important to distinguish it from blood, which signals a more serious underlying health issue. Blood in stool can appear in various ways: bright red, dark red, maroon, or even black and tarry. Bright red blood usually indicates bleeding in the lower digestive tract, such as the colon, rectum, or anus.
Conversely, dark red or black, tarry stools may suggest bleeding higher up in the digestive system, such as the stomach or small intestine. If red stool occurs without recent consumption of red foods, or if accompanied by other symptoms like abdominal pain, dizziness, weakness, unexplained weight loss, fever, or persistent changes in bowel habits, seek medical attention. A healthcare professional can determine the cause and recommend appropriate action.