Stool color deviations from the usual brown can cause concern. Many people wonder if consuming tart cherry juice might lead to a change in stool color, potentially making it appear dark or black. While stool color is influenced by various factors, understanding the reasons helps differentiate benign dietary effects from signs needing medical attention.
Tart Cherry Juice and Stool Color: The Science Behind It
Tart cherry juice can cause stool to appear darker, ranging from dark green to black. This color change is generally temporary and not a cause for concern. The reason is natural pigments called anthocyanins, abundant in tart cherries.
Anthocyanins are a type of flavonoid responsible for the deep red, purple, and blue hues found in many fruits and vegetables. When tart cherry juice is consumed, these powerful pigments travel through the digestive system. As they pass through the intestinal tract, anthocyanins largely retain their dark coloration, which can then be reflected in the stool.
Other Dietary Influences on Stool Color
Beyond tart cherry juice, many other foods and certain medications can also lead to dark or black stool. Common dietary culprits include blueberries, which contain anthocyanins similar to tart cherries, and beets, due to their rich red pigment called betanin. Dark leafy greens, black licorice, and even dark chocolate can contribute to a darker stool color.
Certain over-the-counter medications and supplements are also known to cause this temporary change. Iron supplements, for instance, can make stool appear black or greenish-black as unabsorbed iron interacts within the digestive tract. Additionally, medications containing bismuth subsalicylate, commonly used for upset stomachs, can react with sulfur in the digestive system to form bismuth sulfide, resulting in a harmless black discoloration of the stool.
Recognizing Concerning Stool Changes
While dietary and medicinal influences on stool color are usually harmless, it is important to distinguish these from more serious changes. “True” black, tarry stool, medically known as melena, typically indicates bleeding in the upper gastrointestinal tract, such as the esophagus, stomach, or the first part of the small intestine. This type of stool has a distinct jet-black color, a sticky or tar-like consistency, and often a foul odor, due to the blood being digested as it moves through the digestive system.
Seeking medical attention is advisable if black stool is accompanied by other concerning symptoms. These include dizziness, weakness, lightheadedness, significant abdominal pain, or vomiting blood that resembles coffee grounds. If black stool persists for more than a day or two without a clear explanation from recent diet or medication, or if there is any visible blood, consulting a healthcare professional is important to determine the underlying cause.