The large amount of tannic acid in bananas has a strong astringent effect, which can harden feces and thus cause constipation.
In daily life, many people believe that eating bananas can help with bowel regularity, so some people with constipation often eat them. However, for some people, bananas not only fail to relieve constipation but can actually worsen it. It's no wonder that constipated patients often wonder: why does eating more bananas make it harder to have a bowel movement? Because bananas do not have a laxative effect.
Everyone knows that when bananas are unripe, their peels are green. When peeled, they are too astringent to eat. When ripe, the astringent taste disappears, leaving them soft, sweet, and sticky, making them popular with children and the elderly. Bananas are tropical and subtropical fruits. To facilitate storage and transportation, they must be picked while their peels are still green and stored before they ripen. The bananas we eat in the north are ripened artificially. The astringent taste of raw bananas comes from the large amount of tannic acid they contain. When a banana ripens, although the astringent taste is gone, the tannic acid is still present. Tannic acid has a very strong astringent effect, which can harden feces and cause constipation. The most typical case is that after eating bananas, the elderly and children may not only fail to have their bowels move but can actually experience significant constipation.
There are many foods that can help with bowel regularity, such as coarse grains like apples, sweet potatoes, and corn. Apples are rich in dietary fiber and pectin, so they can have a bidirectional regulatory effect on bowel movements. When constipated, eating more apples can help soften the stool. The pectin in apples can absorb 2.5 times its own volume in water, softening the stool and making it easier to pass, thus relieving constipation. When experiencing diarrhea, the pectin in apples can absorb water from the stool, making loose stools firmer and thus stopping diarrhea. This "bidirectional regulation" of apples is very gentle and is especially suitable for the elderly and infants. In addition, coarse grains like sweet potatoes, corn, oats, and buckwheat are rich in dietary fiber and also have the effect of preventing and treating constipation.