Prune Juice & Diarrhea

Prune juice has a well-deserved reputation as a dietary aid to promote bowel regularity and prevent constipation. Several components of prune juice have a natural laxative effect. If you consume too much prune juice, however, you may experience diarrhea. You may need to experiment to determine how much prune juice your system can tolerate without causing diarrhea.

Sorbitol

Prune juice contains a high concentration of sorbitol, also known as glucitol. This naturally occurring, sweet chemical is a derivative of the sugar glucose and has mild laxative effects. Your intestines digest sorbitol slowly, which means some of the chemical passes through your system undigested. This causes retention of water in your stool, a phenomenon called an osmotic laxative effect. A small dose of sorbitol from prune juice keeps your stool soft and helps promote regular bowel movements. A large amount of sorbitol in your stool, however, may cause watery diarrhea.

Dihydrophenylisatin

Prune juice contains the chemical dihydrophenylisatin, which acts as a mild laxative by stimulating muscle contractions in your bowels. The increased frequency of contractions causes stool to move through your bowels more quickly, reducing the time for water reabsorption in your colon. This effect may contribute to diarrhea if you consume too much prune juice.

Fiber

Fiber promotes bowel activity by adding bulk to your stool. Although prunes contain more fiber than prune juice, a significant amount of soluble fiber remains in the liquid. An 8-oz. glass of prune juice contains approximately 2.6 g of fiber, according to the USDA. Like sorbitol, soluble fiber promotes water retention in your stool, which may lead to diarrhea if you consume a large amount of prune juice.

Accompanying Symptoms

If you have diarrhea caused by consuming too much prune juice, you may also experience abdominal bloating, cramps and increased intestinal gas. Normal bacteria in your intestines break down sorbitol and release gas. The increased bulk and water of your stool contribute to bloating. Cramps may occur due to the stimulant effect of dihydrophenylisatin and the increased bulk of your stool.

How Much Is Too Much?

The amount of prune juice you can consume without developing diarrhea varies from one person to another and depends largely on your tolerance to sorbitol. According to the World Health Organization, laxative effects from sorbitol typically occur with a dose of approximately 50 g daily. An 8-oz. glass of prune juice contains roughly 14 g of sorbitol. To determine your tolerance for prune juice, start by consuming a small amount twice daily and see how your digestive system reacts. Slowly increase your daily consumption until you determine the amount that you can tolerate without diarrhea. Talk with your doctor if you have questions or concerns.