Bananas are rich in dietary fiber, a large portion of which is not digested or absorbed, but it can increase the volume of stool and promote intestinal peristalsis.
Unripe bananas can worsen constipation.
At the same time, bananas contain more than 15% sugar and a large amount of water-soluble plant fiber, which can cause hypertonic secretion of gastrointestinal fluids, thereby drawing water to the solid part and softening the stool for easier excretion. However, these effects are only present in fully ripe bananas. Unripe bananas may have the opposite effect; they contain more tannic acid, which is less soluble and has an astringent effect on the digestive tract, inhibiting the secretion of gastrointestinal fluids and their peristalsis. Consuming too many can lead to or aggravate constipation. Therefore, unripe bananas should not be used to relieve constipation.