Evidence suggests that bananas tend to reduce constipation rather than cause it. They contain dietary fiber that helps make stools softer.

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 low-fiber 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.

Bananas are high in fiber

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 recommended by health professionals to help prevent and relieve constipation (2, 3).

There are two main types of dietary fiber, soluble and insoluble.

Soluble fiber absorbs water, helping stools stay large and soft. This can help improve the movement of stool through your digestive tract. Many plant foods are high in soluble fiber, such as fruits, broccoli, carrots, oats, and beans (4, 5).

Insoluble fiber is the second type. Foods high in insoluble fiber include wheat bran, beans, and whole grains. Insoluble fiber typically provides bulk and helps stimulate bowel activity. However, some sources, such as finely-ground wheat bran, may worsen constipation (6, 7).

Bananas provide both soluble and insoluble fiber. In most cases, increasing fiber intake can help relieve constipation (6, 8)

Bananas are a good source of fiber, which can help relieve constipation.

Green bananas are high in resistant starch

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).

The carbs in a green banana are mostly made up of starch. Starch accounts for up to 70–80% of the dry weight of an unripe banana. A large part of this is resistant starch (11).

As a banana ripens, the amount of starch and resistant starch decreases as they are converted into other types of carbs (11).

Resistant starch functions like dietary fiber, which can help with constipation (6).

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

However, human studies has shown mixed results.

A review of studies found that resistant starch has a positive effect on bowel function in healthy adults. Researchers saw improvements in many markers of bowel health, including higher levels of short-chain fats. However, there was no significant change in bowel movement frequency (13).

Lastly, it’s worth noting that the starches in green bananas may relieve other digestive issues. Cooked green bananas have been shown to relieve acute diarrhea in young children. However, research is ongoing and more evidence is still needed (14, 15).

The resistant starch in green bananas acts like dietary fiber and could help reduce constipation. Green bananas may also provide relief from acute diarrhea.

Some believe bananas cause constipation

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.

Bananas are part of the “BRAT” diet — bananas, rice, applesauce, and toast — that’s sometimes recommended to help you recover from diarrhea or vomiting (16).

These soft, bland foods are thought to be easier to digest, which allows your body to heal.

Although bananas can help you recover from diarrhea, there is no good evidence that they can cause constipation.

In general, experts recommend eating more fruit to help relieve constipation (7, 17, 18).

If you think bananas may be worsening constipation for you or your child, talk with your doctor or a registered dietitian. Removing foods from a child’s diet can lead to nutrititional deficiencies, so it’s important to consult an expert before making big changes.

There is no strong evidence that bananas cause constipation. If you suspect bananas are worsening your constipation symptoms, talk with your doctor or a registered dietitian.

They may improve other aspects of digestive health

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

An older 2011 study examined how eating bananas affected gut bacteria in 34 women with a body mass index (BMI) indicating excess weight (19).

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 less bloating than the group that did not eat bananas.

More recently, a 2020 study examined the effects of banana pulp dietary fibers on mice that were fed a high-fat diet. Eating banana pulp dietary fibers appeared to increase healthy gut bacteria, reduce weight gain, and improve intestinal function in the mice (20).

However, more human studies are needed before strong conclusions can be made.

As a source of fiber, bananas can improve digestion. Some research suggests they may also stimulate the growth of good bacteria, but more evidence is needed.

The bottom line

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

They contain dietary fiber that helps bulk up stools and make them softer.

If you suspect that bananas are worsening constipation, it’s best to talk with your doctor or a registered dietitian.