Fresh plums and prunes are biologically the same fruit, with prunes being dehydrated plums. While both contain the compounds responsible for promoting bowel regularity, the preparation significantly alters the concentration of these substances. This change in density accounts for the widely recognized difference in their effectiveness as a natural remedy for constipation.
Identifying the Key Laxative Components
The laxative properties of both plums and prunes are attributed to a combination of three main components: dietary fiber, the sugar alcohol sorbitol, and phenolic compounds. These elements work through distinct mechanisms within the digestive tract to encourage movement and soften stool. Dietary fiber includes both soluble and insoluble types. Insoluble fiber increases the bulk and weight of the stool, stimulating intestinal muscles, while soluble fiber absorbs water to create a softer consistency.
The sugar alcohol sorbitol functions as an osmotic agent. Because sorbitol is poorly absorbed by the small intestine, it travels into the large intestine where it draws water from surrounding tissues into the bowel lumen. This influx of water hydrates and softens the stool, promoting a bowel movement.
Phenolic compounds, primarily neochlorogenic and chlorogenic acids, also play a supportive role. These compounds stimulate gut motility by increasing the rhythmic contractions of the intestinal muscles that push waste through the colon. They may also act as mild prebiotics, feeding beneficial gut bacteria.
How Drying Alters Potency and Concentration
The process of turning a fresh plum into a prune involves significant dehydration, which is the primary reason prunes are more potent per gram. A fresh plum is approximately 85% water, meaning the laxative components are highly diluted. When the fruit is dried, most moisture is removed, concentrating the fiber, sorbitol, and phenolic compounds into a smaller, denser package.
This concentration results in an increase in active ingredients per serving weight. For example, 100 grams of fresh plums contains about 1.4 grams of dietary fiber, whereas the same weight of prunes can contain over 7 grams. Similarly, the sorbitol content in a fresh plum (approximately 5.4 grams per 100 grams) can increase to nearly 15 grams per 100 grams in prunes.
Because the water has been largely removed, a person can consume a higher dose of the laxative components by eating prunes without feeling overly full. A small handful of prunes delivers a therapeutic dose of both fiber and sorbitol that would require eating several times the weight in fresh plums. The drying process intensifies the existing compounds, creating a more effective natural remedy.
Practical Consumption and Dosage Comparison
The practical difference between the two fruits is evident in the quantity required to achieve a noticeable laxative effect. A typical effective serving to relieve mild constipation is about 50 to 100 grams of prunes, which translates to roughly 5 to 10 pieces. Consuming this small number delivers a concentrated dose of both fiber and sorbitol.
To obtain an equivalent amount of the active compounds from fresh plums, a person would need to consume a much larger volume, often requiring 10 or more whole plums. This volume difference also affects the caloric intake. For example, 100 grams of fresh plums contains approximately 46 calories, while 100 grams of prunes contains around 240 calories. Prunes offer a higher concentration of laxative agents for fewer pieces of fruit, though the total caloric load of an equivalent therapeutic dose is higher in the dried fruit.
Consuming too many prunes too quickly can lead to undesirable side effects due to the high concentration of sorbitol. The osmotic action that draws water into the colon can cause symptoms like excessive gas, abdominal bloating, and even diarrhea if the dose is too high. Introducing prunes gradually, starting with a small number and ensuring adequate water intake, allows the digestive system to adjust to the increased fiber and sorbitol load.