Constipation is a common health problem.

It's characterized by irregular bowel movements and hard stools that are difficult to pass.

There are many causes of constipation, ranging from a poor diet to a lack of exercise.

Some claim that bananas cause constipation, while others say they help prevent it.

This article analyzes the evidence to determine whether bananas cause or relieve constipation.

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Bananas are one of the world's most popular fruits. They're a convenient snack and incredibly healthy.

Rich in several important vitamins and minerals, bananas are also relatively high in fiber, with one medium banana containing about 3.1 grams of this nutrient (1).

Fiber has long been claimed to help prevent and relieve constipation (2, 3).

Soluble fiber absorbs water, helping stools stay large and soft. This may help improve the movement of stool through your digestive tract (4).

However, evidence supporting the idea that fiber helps relieve constipation is conflicting and surprisingly weak, especially given how many health professionals recommend a high fiber intake to their constipated patients (5, 6).

Some studies indicate that soluble fiber can help relieve constipation. On the contrary, other studies suggest that reducing dietary fiber intake may help in some cases (7, 8).

Whether increasing your fiber intake helps relieve constipation seems to vary by individual. The type of fiber you ingest also matters.

Summary Bananas are a fairly good source of fiber, which may help relieve constipation in some people. However, the evidence on this is rather conflicting.

Resistant starch is a complex carb that has fiber-like properties.

It escapes digestion in the small intestine and ends up reaching the large intestine, where it feeds the friendly bacteria that reside there (9).

Feeding these bacteria is a good thing. They produce short-chain fats, which contribute to digestive health and have beneficial effects on metabolism (10).

Before it ripens, a banana is almost entirely starch, which accounts for up to 70–80% of its dry weight. A large part of this starch is resistant starch.

As a banana ripens, the amount of starch and resistant starch decreases and is converted into sugars (11).

Resistant starch functions like soluble fiber, which can help with constipation (7).

One study found that feeding constipated mice resistant starch from bananas sped up the movement of stools through their intestines (12).

Lastly, it's worth noting that green bananas have been used to treat diarrhea in children and adults. These properties are attributed to their high content of resistant starch (13, 14, 15).

Summary The resistant starch in green bananas acts like soluble fiber and has been used to treat constipation. It may also help reduce diarrhea.

Many articles on the internet claim that bananas cause constipation. Studies haven't confirmed this, but some people believe they are a risk factor for this condition.

In one study, German researchers investigated the perceived effects of various food items on stool consistency. They surveyed three groups:

  • IBS: 766 patients had irritable bowel syndrome (IBS), where constipation was a major symptom.
  • Constipation. 122 patients were constipated.
  • Control. 200 healthy individuals served as the control group.

When the 3 groups were asked which foods or beverages caused constipation, bananas were mentioned by 29–48% of respondents.

In fact, only chocolate and white bread were named more often (16).

Summary There is no strong evidence that bananas cause constipation, although one survey found that some people believe they do.

Most people tolerate bananas well, at least when consumed in moderation.

They improve digestive health and have prebiotic effects, meaning they feed your friendly gut bacteria and stimulate their growth.

One study including 34 women with excess weight examined how eating bananas affected gut bacteria (17).

After the women ate two bananas per day for two months, the researchers observed increases in beneficial bacteria called Bifidobacteria. However, the effect wasn't statistically significant.

What's more, the banana group reported improvements in digestive symptoms like bloating and stomach pain.

Summary Bananas can improve digestion. Some research shows they may also stimulate the growth of good bacteria.

The evidence suggests that bananas tend to reduce constipation rather than cause it.

However, researchers have also found that some people think bananas make them constipated.

If you feel that bananas make you constipated, simply eat fewer of them. If that doesn't work, try eliminating them from your diet completely to see if that helps.

A food that relieves constipation for you may have the opposite effect on someone else.